FEDERAL COURT OF AUSTRALIA Gambro Pty Limited v Fresenius Medical Care Australia Pty Limited [2004] FCA 323 INTELLECTUAL PROPERTY – PATENTS – patent for a system for the preparation of fluid intended for medical procedures such as haemodialysis – respondent found to have infringed the patent in suit – cross claim – whether lack of novelty, lack of utility, lack of sufficiency of description, lack of fair basing and obviousness. Patents Act 1952 (Cth) Patents Act 1990 (Cth) Abbott Laboratories v Corbridge Group Pty Ltd [2000] FCA 1713, referred to Abbott Laboratories v Corbridge Group Pty Ltd [2002] FCAFC 314; [2002] AIPC 91-824, referred to Aktiebolaget Hässle v Alphapharm Pty Limited [2002] HCA 59; 194 ALR 485, referred to Allsop Inc v Bintang Ltd (1989) 15 IPR 686, cited Bartlem Pty Ltd v Cox Industries (Australia) Pty Ltd [2002] FCAFC 224; 55 IPR 449, cited Bristol-Myers Squibb Company v FH Faulding & Co Ltd (2000) 46 IPR 553, cited British United Shoe Machinery Company Ltd v A Fussell & Sons Ltd (1908) 25 RPC 631, referred to Chiron Corporation v Organon Teknika Limited [1994] FSR 202, cited Clark v Adie (1875) 10 Ch App 667, referred to Codex Corporation v Racal-Milgo Ltd [1983] RPC 369, cited Commonwealth Industrial Gases Limited v MWA Holdings Pty Limited (1970) 180 CLR 160, cited Decor Corporation Pty Ltd v Dart Industries Inc (1988) 13 IPR 385, referred to Eastern Counties and the London and Blackwall Railway Companies v Marriage (1860) 9 HLC 32; 11 ER 639, cited Flexible Steel Lacing Company v Beltreco Ltd [2000] FCA 890; 49 IPR 331, referred to General Clutch Corporation v Sbriggs Pty Ltd (1997) 38 IPR 359, discussed General Tire & Rubber Company v Firestone Tyre & Rubber Company Limited [1972] RPC 457, cited Graham Hart (1971) Proprietary Limited v SW Hart & Company Proprietary Limited (1976) 141 CLR 305, cited Hill v Evans (1862) 31 LJ Ch 457; 4De G F & J 288; 45 ER 1195, cited HPM Industries Proprietary Limited v Gerard Industries Ltd (1957) 98 CLR 424, cited ICI Chemicals & Polymers Ltd v Lubrizol Corporation Inc (2000) 49 IPR 513, cited Interlego AG v Toltoys Proprietary Limited (1973) 130 CLR 461, cited Kimberly–Clark Australia Pty Limited v Arico Trading International Pty Limited [2001] HCA 8; 207 CLR 1, cited Meyers Taylor Pty Ltd v Vicarr Industries Limited (1976) 137 CLR 228, discussed Minnesota Mining & Manufacturing Company v Beiersdorf (Australia) Limited (1979) 144 CLR 253, discussed Minnesota Mining and Manufacturing Co v Tyco Electronics Pty Ltd [2002] FCAFC 315; (2002) 56 IPR 248, cited N Guthridge Limited v Wilfley Ore Concentrator Syndicate Limited (1906) 3 CLR 583, cited National Research Development Corporation v Commissioner of Patents (1959) 102 CLR 252, followed Nicaro Holdings Pty Ltd v Martin Engineering Co (1990) 91 ALR 513, cited Olin Corporation v Super Cartridge Co Pty Ltd (1976) 180 CLR 236, referred to Populin v HB Nominees Pty Ltd (1981) 59 FLR 37, referred to Radiation Limited v Galliers and Klaerr Proprietary Limited (1938) 60 CLR 36, referred to RD Werner & Co Inc v Bailey Aluminium Products Pty Ltd (1989) 25 FCR 565, referred to Rehm Pty Ltd v Websters Security Systems (International) Pty Ltd (1988) 81 ALR 79, referred to Rhone-Poulenc Agrochimie SA v UIM Chemical Services Pty Ltd (1986) 12 FCR 477, cited Sabre Corporation Pty Ltd v Russ Kalvin's Hair Care Company (1993) 46 FCR 428, discussed Sunbeam Corporation v Morphy-Richards (Australia) Pty Ltd (1961) 180 CLR 98, referred to C. Van der Lely NV v Bamfords Limited [1963] RPC 61, cited Walker v Alemite Corporation (1933) 49 CLR 643, referred to Welch Perrin & Co Pty Ltd v Worrel Company Proprietary Limited (1960) 106 CLR 588, referred to. Wellcome Foundation v VR Laboratories (Aust) Proprietary Limited (1980) 148 CLR 262, cited Woolworths Ltd v WB Davis and Son Ltd Inc (1942) 16 ALJ 57, cited A Selection of Broom's Legal Maxims (10th Ed 1939) pp 461-62 Blanco White Patents for Inventions (4th Ed) Blanco White Patents for Inventions (5th Ed) GAMBRO PTY LIMITED AND ANOR v FRESENIUS MEDICAL CARE AUSTRALIA PTY LIMITED NG 474 of 1997 ALLSOP J 25 MARCH 2004 SYDNEY IN THE FEDERAL COURT OF AUSTRALIA NEW SOUTH WALES DISTRICT REGISTRY NG 474 of 1997 BETWEEN: GAMBRO PTY LIMITED FIRST APPLICANT SECOND CROSS-RESPONDENT GAMBRO LUNDIA AB SECOND APPLICANT FIRST CROSS-RESPONDENT AND: FRESENIUS MEDICAL CARE AUSTRALIA PTY LIMITED RESPONDENT CROSS-CLAIMANT JUDGE: ALLSOP J DATE OF ORDER: 25 MARCH 2004 WHERE MADE: SYDNEY THE COURT ORDERS THAT: 1. the applicants file and serve within fourteen days draft short minutes of order conformable with the reasons for judgment published today; 2. the matter stand over to a date to be fixed for the hearing of argument, if any, as to the form of those orders and for the making of orders. Note: Settlement and entry of orders is dealt with in Order 36 of the Federal Court Rules. IN THE FEDERAL COURT OF AUSTRALIA NEW SOUTH WALES DISTRICT REGISTRY NG 474 of 1997 BETWEEN: GAMBRO PTY LIMITED FIRST APPLICANT SECOND CROSS-RESPONDENT GAMBRO LUNDIA AB SECOND APPLICANT FIRST CROSS-RESPONDENT AND: FRESENIUS MEDICAL CARE AUSTRALIA PTY LIMITED RESPONDENT CROSS-CLAIMANT JUDGE: ALLSOP J DATE: 25 MARCH 2004 PLACE: SYDNEY REASONS FOR JUDGMENT 1 INDEX Introduction [2]-[7] Background [8]-[53] The Patent [54]-[102] Infringement [103]-[187] Novelty [188]-[328] Fair Basis, Sufficiency and Utility [329]-[344] Obviousness [345]-[429] Residual Rulings on Evidence [430]-[446] Conclusions [447]-[449] Introduction 2 The second applicant is a Swedish company which had granted to it on 5 February 1988 Australian letters patent 595423 (the Patent). 3 The first applicant, which is the Australian subsidiary of its Swedish parent, the second applicant, is the exclusive licensee of the Patent. 4 The Patent embodies a system for the preparation of fluid intended for medical procedures such as haemodialysis. A brief history of the Patent is found at [9] to [11] of the reasons for judgment of Tamberlin J in dealing with the application for amendment of the claims ([1999] FCA 1848; 48 IPR 625, 627-28). Three matters should be noted at this point. First, the above expression of the embodiment of the Patent should be taken as neutrally expressed. There is an important question as to the ascertainment of the proper field of enquiry for obviousness or inventive step. The expression of the characterisation of the invention is not irrelevant to this issue. Secondly, the relevant prefix used in the specification and claims is the American usage "hemo". Except when quoting the specification or claims, I will use "haemo". Thirdly, unless the context otherwise makes clear, my use of the word "invention" is conformable with Schedule 1 to the Patents Act 1990 (Cth) (the 1990 Act), and includes "alleged invention". 5 The parties approached the proceedings on the basis that the relevant priority date was 6 February 1987 ("the Priority Date"). 6 The second applicant designs, manufactures and sells (and did so at the Priority Date) medical equipment including machines that are used for haemodialysis and related treatments, all of which are described below. The respondent is the Australian subsidiary of a German company, which (by itself and through other companies), no doubt amongst other activities, designs, manufactures and sells (and did so at the Priority Date) machines that are also used for haemodialysis and related activities. The first applicant and the respondent are (and were at the Priority Date) direct competitors in Australia. 7 The applicants allege that after about September 1996 the respondent, in Australia, infringed the Patent by selling, hiring or otherwise disposing of, machines and articles which infringe the claims in the Patent. The respondent denies infringement; and, further, in its cross claim, applies under s 138(1) of the 1990 Act for revocation of the Patent on the grounds of lack of novelty, lack of utility, lack of sufficiency of description, lack of fair basing and obviousness. Background haemodialysis 8 Dialysis (that is without the prefix "haemo") involves the transport of solutes across a semi-permeable membrane. Haemodialysis is a form of dialysis where the blood of a patient suffering impaired kidney function is taken from the body and conducted along one side of a semi-permeable membrane in a dialyser or artificial kidney, at the same time as dialysis fluid passes along the other side of the membrane. By this process, toxins and other substances that would ordinarily be removed from the blood by the properly functioning kidney and thereafter excreted, are removed into the passing dialysis fluid. The process also removes various salts as well as fluid from the blood. 9 In haemodialysis, the toxins are removed from the patient's blood mainly by the process of diffusion (the movement of solutes through the membrane from a concentrated solution to one that is more dilute), by osmosis (the movement of solvent through a semipermeable membrane from a dilute solution to one that is more concentrated) and by ultrafiltration (the movement of fluid through a molecular sieving membrane by application of a pressure gradient). 10 The principles of diffusion dialysis were first elucidated in the 1850s. Successful dialysis therapy was delayed for a century by the lack of an effective anti-coagulant and an effective membrane. By the 1940s, scientific developments had produced dialysis systems with clinical potential. By 1960, haemodialysis was undertaken in intensive care units with continuous nurse/doctor observation. By the mid-1960s, however, advances enabled the first unattended home haemodialysis to be undertaken. 11 The process, it should be understood, is a means of achieving the long term survival of patients with renal failure. There is an inherent danger in the technique, involving, as it does, the recirculation, excorporeally, of the patient's blood a number of times over a period of hours. Crucial to the safe and successful operation of the technique is the accurate composition and temperature of the fluid used, within clinically set parameters. The fluid for haemodialysis contains salts and electrolytes so as to correspond as closely as possible to normal blood. 12 Ions in the blood are buffered by the body's natural buffer, bicarbonate. The function of bicarbonate in the body is to act as a buffer against extreme pH changes. The bicarbonate level in the blood is regulated by the kidneys, keeping the pH of normal blood within very narrow limits, around pH 7.4. A solution is said to be buffered if it resists change in the activity of an ion on the addition of substances that are expected to change the activity of the ion. A buffer is a substance that imparts this resistance to a solution. early techniques of haemodialysis 13 In early techniques, using haemodialysis baths, the buffer used in the dialysis fluid was bicarbonate – the body's natural buffer. Ms Elizabeth Yuill, a highly experienced nurse and nurse manager gave evidence as to how dialysis was conducted in Australia from the mid-1970s, after she moved from Wellington, New Zealand, where she had begun her work in a renal unit in 1969. I accept her evidence as to the carrying out of the prior art of techniques and machines. Her evidence of the mechanisms employed with the early use of bicarbonate as a buffer illustrated the practical difficulties then encountered. A large (100 to 120 litre) tank, with a heater, was gradually filled with water. As it was filling, a nurse would tip a prescribed, pre-measured quantity of dry salts into the tank. Once the tank was full to the correct level, the nurse would stir manually with a large paddle until the solute was visibly dissolved. Through the use of a pump on the tank, the fluid could be agitated to assist in dissolution. The nurse would then test the solution. If the solution was not at the correct concentration, it would be discarded. This process of preparation had to take place shortly prior to a dialysis treatment because the solution was susceptible to bacterial growth, other contamination and deterioration of chemical composition; in particular, the bicarbonate buffer was unstable in solution. 14 This technique was arduous, time-consuming and provided significant room for inaccuracy and error. 15 There were different systems for using this large volume of bicarbonate buffered dialysate. There were recirculating systems in which the artificial kidney was immersed in the tank. There were also recirculating single pass systems in which a smaller tank was used into which the artificial kidney was placed in fluid pumped from the larger tank; there was some recirculation in the smaller tank for a time until fluid was pumped out and replaced by fresh fluid pumped from the larger tank. important changes in the 1960s and 1970s – the move to acetate buffer 16 In Australia, from the early to mid-1970s, (in other countries perhaps somewhat earlier) the treatment of patients with haemodialysis changed importantly. Fluid proportioning machines were developed in the 1960s which mechanically provided for the accurate mixing of fluid concentrate with water making a diluted solution appropriate for use in the dialysis procedure. These machines allowed for the continuous (and contemporaneous) production of dialysis fluid using a proportioning device, mixing water with a fluid concentrate in given proportions. This advance allowed for quantities of available buffer in a liquid concentrate form to be mixed with water. 17 The disadvantages of bicarbonate were evident from the existing procedures: it was not stable in solution and its use required careful technician attendance to the production and use of the fluid. Sodium acetate was an equivalent. Sodium acetate is a source of metabolic base buffer, being converted into bicarbonate by the liver. Sodium acetate had the advantage of being stable in solution for long periods of time and was inexpensive. Thus, acetate concentrate fluid began to be used, mixed with water by the proportioning machines, to produce the dialysis fluid. The acetate concentrate was sold in five litre pre-prepared containers. 18 The advance of the proportioning device and the use of acetate buffer concentrate allowed for the contemporaneous, or on-line, production of dialysis fluid. 19 The water used in the process was heated to a temperature equivalent to that of blood in the body. Before passing to the dialysis procedure the temperature and conductivity of the fluid produced by the proportioning machine were checked for tolerance within prescribed limits. If outside those limits, the solution by-passed the dialysis machine. If within the limits, the fluid was used in a "single pass" treatment and then discarded. 20 The use of proportioning dialysis machines reduced by a factor of 20 to 30 the volume of solution which had to be handled on site. No longer was there a need for large tanks of 100 to 120 litres. Patients could, with a degree of training, treat themselves at home using acetate concentrate in 5 litre containers. 21 By the early 1970s, most, if not all, dialysis centres and renal units in Australia were phasing out the use systems requiring large 100 to 120 litre batch preparations. By the end of the 1970s, the majority of dialysis centres, hospital renal units and patients treating themselves at home in Australia were using liquid acetate concentrates and a proprietary machine called a Drake Willock single pass proportioning dialysis machine to perform haemodialysis treatments. a move back to bicarbonate buffer 22 The above was the mechanism for haemodialysis until the early 1980s. From the introduction of acetate concentrate up to the early 1980s, there were advances in the biomedical aspects of haemodialysis. There was the development of more efficient and larger surface area dialyzers which shortened dialysis treatment times. With these new techniques, bicarbonates were more rapidly removed from the bloodstream and the acetate from the fluid was more rapidly taken up by the blood. Some patients had greater difficulty metabolising acetate than others; so, the more rapid the acetate take up, the more difficult some patients found the procedure. Ms Yuill described the difficulties that acetate buffer caused in patients who were intolerant to it: hypotension, nausea, vomiting and headaches. Thus, for these clinical reasons, by the early 1980s bicarbonate once again came to be used as a buffer for dialysis fluid. 23 In the early 1980s, proportioning machines were developed which were capable of mixing bicarbonate buffered concentrate solution with water, as well as an acid concentrate solution to form dialysis fluid. Existing acetate proportioning machines were replaced or modified. The greater complexity in the proportioning machines was brought about by the use of two separate concentrate solutions that were mixed separately with the water to create the dialysis solution. One concentrate, which became known as the "A" concentrate, contained all the electrolytes necessary for the dialysis fluid and an acid dissolved in water. The A concentrate was purchased as a commercially prepared (and stable) concentrate solution in a 5 litre container. The other concentrate, the so called "B" concentrate, contained sodium bicarbonate buffer dissolved in water, together, sometimes, with some sodium chloride. The A and B concentrates could not be premixed together (as a mixed concentrate), because the concentration and pH of the A concentrate would cause the bicarbonate in the B concentrate to react with the calcium in the A concentrate to form a calcium carbonate precipitate. 24 Early in the 1980s, 9 or 10 litres of B concentrate would be made up on-site by nurses, shortly prior to the dialysis treatment, by dissolving a pre-measured amount of sodium bicarbonate or sodium bicarbonate and sodium chloride, as fine powder, in a measured volume of water. The powder was purchased in bottles containing precise amounts of one or other or both of the sodium bicarbonate and sodium chloride. Pre-preparation of the B solution in water any period of time before it was needed was not done because of the well understood problems of a tendency for bacterial growth, other contamination and precipitation. 25 The proportioning machines thus now mixed water with A concentrate and also with B concentrate. 26 Early in the use of the A and B concentrates, nurses prepared B concentrate each shift before the commencement of haemodialysis treatment. Ms Yuill described the process in her affidavit as follows: The nurse took an empty 11 litre plastic wide necked container from a storage area of the Renal Unit and placed it on the floor of the Renal Unit under a tap on the wall in the Unit. The nurse then filled the container with water from the tap up to a 9 litre line marked on the container. The nurse then tipped the dry Part B into the water. The nurse then stirred the solution with a wooden paddle for a couple of minutes and then left the solution to settle for a couple of minutes. The nurse then stirred the concentrate solution again for a number of minutes, and again left it to settle. This would be repeated 3 to 4 times or for as long as it took to visibly dissolve all of the dry Part B in order to produce a B concentrate solution of the correct concentration. 27 Thus produced, the full B concentrate container was taken to the dialysis machine; the nurse also took the pre-prepared 5 litre A concentrate container to the machine. A wand from the dialysis machine was placed into each container. The machine was connected to a water source. The water drawn from such source was heated. Priming took place with the proportioning device mixing the heated water with A and B concentrates. The blood lines were primed with saline. Once the temperature and conductivity of the fluid was within the prescribed parameters, the treatment would begin. The dialysis fluid was pumped through the artificial kidney. Once the patient was connected to the machine by arterial and venous needles, the patient's blood was pumped through the artificial kidney and back to the patient. 28 Over the course of treatment, the dialysis machine continuously prepared the dialysis fluid by proportioning heated water with the A concentrate solution and the B concentrate solution, each in the correct ratio at the same rate as the dialysis machine passed dialysis fluid through the artificial kidney. By the end of the treatment, almost all of the A concentrate solution and the B concentrate solution were used and the containers were almost empty. 29 If the nurse had not dissolved the B concentrate solution fully, the conductivity meter would cause intermittent alarms that would divert fluid to by-pass the artificial kidney. Any residual powder drawn into the machine would also cause difficulties. 30 In Ms Yuill's experience pharmacy departments of hospitals sometimes undertook the responsibility for preparing the B concentrate. 31 The correct mixture of ions, buffer and water is important. A solution too dilute with water will cause the patient's blood cells to take up water and swell; if the blood cells burst this is a serious condition called haemolysis. If the fluid has too high a concentration of ions the patient's blood cells lose water and shrink which is called crenation. This is why all systems used some form of conductivity and temperature measurements to control a fail safe by-pass just prior to the haemodialysis fluid entering the artificial kidney. 32 Whilst the preparation of the B concentrate by pharmacy departments, rather than by busy nurses, may have improved the reliability of the B concentrate used, it created logistical difficulties. Heavy 10 litre containers of B solution had to be moved around the hospital and empty containers returned to the pharmacy department. 33 Also in Ms Yuill's experience, pharmacy departments sometimes provided magnetic stirrers to nurses together with instructions on their use in an effort to return the responsibility for B concentrate preparation to nurses at the site of the haemodialysis treatment. 34 The disadvantages of a laborious and time-consuming process of the above kind was clear; this was especially so in relation to a solution, the preparation of which was required to be thorough and precise. In a busy hospital, such as Westmead, in Sydney, where Ms Yuill worked in the 1980s, there were 5 nurses responsible for performing between 10 and 20 haemodialysis treatments a day. Notwithstanding the obvious difficulties of on-site B concentrate preparation, the great majority of hospital treatments were undertaken by the A and B concentrates being mixed and delivered by proportioning dialysis machines, because of the clear clinical advantages of using a bicarbonate buffer, over the use of only acetate. 35 Home dialysis patients, however, generally continued to treat themselves with acetate buffered fluid despite attendant clinical disadvantages. Though some, with instruction, could prepare the B concentrate, as the nurses did on-site. commercial preparation and sale of B concentrate 36 In the mid-1980s, B concentrate began to be sold commercially pre-prepared. The first applicant sold such a product in the mid-1980s. The B concentrate was prepared in controlled preparation plants and delivered in 10 litre containers. The laborious task of on-site preparation, with its other attendant disadvantages, was done away with and a more reliable control of quality was achieved. The preparation of the concentrate under controlled industrial conditions meant that B concentrate had a longer "shelf life" than solutions manually produced on site, though it was more expensive. Further, bacterial contamination and degradation of the concentrate over time remained a problem. Solutions of sodium bicarbonate tend to release carbon dioxide over time, thereby changing the pH of the concentrate. The useful life of the concentrate was a matter of a few months, at most. Careful inventory storage was required. With deliveries of 10 litre containers sufficient for a number of weeks, further storage capacity was required; there was also the requirement of movement of containers (full and empty) to and from dialysis treatment sites. Further, there was a considerable increase in plastic (container) waste disposal. 37 Ms Yuill was in a position to understand how most hospitals and renal units in Australia conducted themselves in relation to dialysis. Her evidence was that "the use of liquid B concentrate was adopted very quickly and almost universally by hospitals, renal units and dialysis centres in Australia. By 1987 very few (if any) hospitals, renal units, dialysis centres and home dialysis patients in Australia were still manually preparing batches of B concentrate solution on site." 38 Ms Yuill described the residual difficulties present in the use of A and B pre-prepared and supplied concentrates as: (a) the need for storage space in hospitals or homes, (b) the increase in plastic waste, (c) though with a longer shelf life, the propensity of the concentrate to bacterial contamination and decomposition after a relatively short shelf life, and (d) the need to lift and deploy heavy 10 litre containers. aspects of available machines 39 Various types of proprietary machines were in use in Australia before the Priority Date. Mr Terrence West gave evidence. His affidavits were filed on behalf of the applicants. He was cross-examined. Mr West was a senior dialysis technician. He had been a dialysis technician since 1974. He trained as an electrical apprentice at BHP in Newcastle, where he became an electrician. While employed by BHP he completed further training at Newcastle College of Technical and Further Education, gaining an Advanced Electronics Certificate and a Certificate in Electrical Engineering. In due course, I will deal with the question of the place of some of Mr West's evidence in the context of the topic of the "skilled addressee". At this point, it only need be said that from the mid-1970s Mr West had a close working familiarity with the operational mechanics of dialysis machines in Australia directly from his employment at Royal Newcastle Hospital and at the Hunter Area Health Service, from his participation in conferences and seminars, from reading journals, from instruction from manufacturers of machines, and from consultation with the editors of a standard journal on dialysis. I accept his evidence as to how dialysis was undertaken before the Priority Date, and as to his experience in connection therewith. 40 Mr West was intimately familiar with the mechanics and electronics of the machines, enabling him to maintain and, where necessary, adapt them. For instance, when bicarbonate concentrate began to be used again in the early 1980s, Mr West altered and upgraded the existing Drake Willock machine at Royal Newcastle to prepare the dialysis fluid from water and the acid and bicarbonate concentrate solutions, rather than from water and acetate concentrate solution. 41 For present purposes, in describing the technology of, and techniques used in, haemodialysis before the Priority Date, it is important to understand some of Mr West's evidence about the various machines in use. 42 There were a number of different proportioning systems in dialysis machines sold and used in Australia before the Priority Date. Some such devices used a conductivity measurement placed immediately after a mixing point to regulate the flow of concentrate into that mixing point. After a point of mixing of A or B concentrate with water the conductivity was measured which measurement controlled the inflow of the concentrate to the water or fluid line. Thus, if concentrate level was rising its injection into the mixing point could be lessened, and so forth. This was a method of regulating the correct mixture of the dialysis fluid. Some machines, such as the well-known "Drake Willock 4015", did not employ a conductivity measurement to regulate flow of concentrate into the water, but rather used fixed volume proportioning systems with metering cylinders. It is unnecessary to describe these kinds of pumps in any detail, but they relied on fixed volumes to bring about reliable pumping of concentrate into the water or fluid line. 43 Dr Klaus Schindhelm, an eminent clinical and biomedical engineer, was called by the respondent. I will later deal with his evidence in relation to the question of the assessment of obviousness and other issues. For present purposes, it is necessary only to note that early in his first affidavit Dr Schindhelm appeared to state that standard dialysis machines before the Priority Date all had conductivity controlled mechanisms regulating the flow of concentrate solution into the water or fluid line. That is not the case. The textbook exhibited by Dr Schindhelm supported the evidence given by Mr West in this regard. Indeed, the cross-examination of Professor Schindhelm made that clear that there were both fixed volume proportioning means, and conductivity measuring and flow regulating means used in dialysis machines before the Priority Date, and that his evidence in chief in his affidavit should not be taken to have intended to say that all dialysis machines at the Priority Date had, or needed to have, conductivity controlled mechanisms regulating the flow of concentrate solution into the water or fluid line. 44 Importantly, and Mr West himself stressed this, all dialysis machines had "fail safe" temperature and conductivity measuring devices to ensure that the dialysis fluid, before passing into the artificial kidney, fell within the stated parameters of temperature and concentration. Should it not do so, the fluid by-passed the artificial organ. 45 A further aspect of the dialysis machines sold and used in Australia before the Priority Date to be noted is that some mixed the A concentrate with water upstream of the point of mixture of the B concentrate, and some mixed the A concentrate downstream of the point of mixture of the B concentrate. The standard texts on dialysis and dialysis machines did not prescribe one order over another. 46 Also, from the evidence of Ms Yuill and Mr West, I find that the method of making the B concentrate solution on site by nurses or technicians was the adding of powder to water and mixing by stirring the mixture in the container. I say this because Dr Schindhelm stated, in [33] and [34] of his first affidavit, dealing with general background principles, that: 33. There are two broad types of method known in chemistry for dissolving a soluble salt in water, that is: (a) placing the salt in the container with the water and mixing them together (for example by stirring or shaking); and (b) placing the salt in a container and passing the water through the bed of that salt. 34. Method (b) is used for salts (such as bicarbonate) with a lower solubility. Common applications of method (b) described in paragraph 33 above are the addition of fluoride salts to drinking water and of fertiliser to irrigation water or any other salt with low solubility eg sodium bicarbonate. 47 It will be necessary to return to this aspect of the evidence in dealing with obviousness. For now, it is sufficient to note that in hospitals and renal units, in Australia before the Priority Date, staff did not use the method of dissolution referred to by Dr Schindhelm in [33(b)] of his first affidavit. I should note, however, that no evidence, from either side, was led as to how commercial entities in Australia dissolved the B concentrate powder for production of the pre-mixed B concentrate sold commercially in the mid-1980s. haemofiltration and haemodiafiltration 48 Two cognate techniques to treat patients with severely impaired renal function are haemofiltration and haemodiafiltration. These are other treatments whereby a patient's blood is treated excorporeally. 49 In haemofiltration, the patient's blood is passed along one side of a very permeable membrane in an artificial kidney. Toxins and waste move from the blood by convective transport together with water plasma across the very permeable membrane. Haemodiafiltration is a hybrid procedure incorporating haemodialysis and haemofiltration. One benefit of haemofiltration and haemodiafiltration is that relatively large molecules which have built up in the blood and which are too large to pass through a conventional haemodialysis membrane can be extracted. The greater ease of passage of toxins, waste and plasma through the very permeable membrane leads to the need for a large volume of sterile isotonic replacement fluid to replace the fluid removed from the blood. This replacement fluid, which is not returned, is continuously added to the blood in the venous return line (after the artificial kidney) or in the arterial take off line (before the artificial kidney). In the haemofiltration, no dialysis fluid passes through the dialyser (or "haemofilter") on the other side of the membrane. In haemodiafiltration, dialysis fluid passes through the dialyser on the other side of the membrane, and replacement fluid is infused into the venous return blood line or the arterial take off line. 50 Before the Priority Date, the replacement fluid used in haemofiltration and haemodiafiltration was a sterile lactate buffered solution purchased in commercially prepared batches to minimise the risk of bacterial contamination. Lactate buffered replacement fluids were used to avoid precipitation of calcium salts which would occur with a bicarbonate buffer. Considerable quantities of replacement fluid were required: 30, and sometimes up to 50, litres for haemofiltration, and 20 litres for haemodiafiltration. The fluid was bought in 5 litre bags. 51 The metabolising of lactate buffered replacement fluid caused similar problems to patients as found with metabolising acetate. Not only was the use of pre-prepared fluid labour intensive, but also the fluid was relatively expensive. Ms Yuill described the administration and difficulties of these procedures before the priority date as follows: The hospital purchased the replacement fluid in sterile 5 litre bags, so on average five or six 5 litre bags were required for one procedure. In practice, this meant that the administration of haemofiltration and haemodiafiltration procedures was very labour intensive. The nurse was required to carry and lift five or six 5 litre bags from the store room to the machine, and then lift each bag to hang it from a stand under the machine so that the machine could pump the replacement fluid into the venous return line from the dialyser to the patient's arm. Problems such as those experienced by dialysis patients metabolising acetate … were also experienced with patients treated with lactate buffered replacement fluid in haemofiltration and haemodiafiltration. Haemofiltration and haemodiafiltration procedures required especially modified machines, were expensive to perform due to the cost of the pre-prepared replacement fluid, and were labour intensive. Patients treated with haemofiltration and haemodiafiltration also required closer monitoring during the treatment than patients treated with conventional haemodialysis. As a result, most hospitals and dialysis units, including the Dialysis Unit at Westmead Hospital, did not use haemofiltration and/or haemodiafiltration routinely until about 1989. 52 From time to time in these reasons, I have used and will use the expression "haemodialysis and related procedures" to mean haemodialysis, haemofiltration and haemodiafiltration. 53 Thus, to summarise: To the extent that there were difficulties with the efficient and convenient preparation and use of bicarbonate buffer, this had been evident in Australia since the early 1980s when the clinical need to move away from single acetate buffer became pressing. Indeed, the disadvantages of on-site contemporaneous production of bicarbonate buffer solution brought about by the instability of the solution and its proneness to contamination had been known for decades. For a time, those difficulties had been solved or avoided by the use of acetate buffer. The advances in the science of dialysis overtook, however, single acetate use. Thus, before the Priority Date, for at least some years, the optimal clinical approach to haemodialysis required the preparation in situ of B concentrate, or the more expensive purchase of pre-prepared containers of B concentrate. In either case, problems existed: bulk, the need for storage, and so forth. The chemical and physical properties of the components of the concentration in question were well known. The Patent the body of the specification 54 The Patent, and in particular the claims defining the invention, must be read and understood in the light of the amendment to the claim dealt with by Tamberlin J. As can be seen from his Honour's reasons for judgment, and as shall be seen below, the claims are narrower and more specific than some parts of the body of the specification. 55 Below the heading "Title" the following appears on page 1a: A system for preparing a fluid intended for a medical procedure by mixing at least one concentrate in powder form with water and a cartridge intended to be used in said system. [Capitalisation in original] 56 The amendments to the claims can be best appreciated by understanding that 81 out of the 88 claims in the Patent commence, whether expressly or by incorporation, with the following: A system for preparing a dialysis or replacement fluid or a component fluid thereof 57 This is to be compared with the title (above): "a fluid for a medical procedure". 58 Under the heading "Field of the Invention" there appears a paragraph that was not amended. It states as follows: The present invention relates to a system for preparing a fluid intended for a medical procedure and, more particularly, to a system for preparing such a fluid by mixing of at least one concentrate in powder form with water. The system of the present invention is intended, in particular, for the preparation of fluids for use in connection with medical procedures such as hemodialysis, hemodiafiltration and hemofiltration. For instance, the system of the present invention may be used in connection with the preparation of a dialysis fluid for use in connection with hemodialysis, as well as used for preparation of replacement fluids used in connection with hemofiltration or hemodiafiltration. To those skilled in the art, it will be apparent moreover that the system of the present invention can be used in connection with other medical procedures or treatment where a fluid suitable for the treatment is obtained from mixing of water with at least one concentrate in powder form, such as, for example, the production of flushing fluid for cleaning of wounds and the like. 59 Leaving aside, at this point, the width of the terms of the above paragraph under the heading "Field of the Invention" beyond haemodialysis, haemofiltration and haemodiafiltration (emphasised by the respondent), one can see that insofar as the invention is directed to those procedures, it is directed to the preparation of dialysis and replacement fluid by mixing at least one concentrate in powder form with water. 60 An important question is the identification of the relevant person "skilled in the art". One matter should be noted at this point: the field is the preparation of a fluid, and even if it is restricted to the preparation of dialysis fluid for haemodialysis or replacement fluid for haemofiltration or haemodiafiltration, the field is not the manufacture of the whole of the relevant machine, but rather the preparation of a fluid intended for use in a dialysis machine. 61 The respondent submitted that the relevant field of discourse remained at the wider general level in the specification, unchanged by the amendments. One can see, the respondent submitted, that the skilled addressee was not merely the person whose only experience and exposure was as a dialysis technician, but rather, that the specification can be seen as directed to the person who could perceive and understand a broader utilisation of the invention beyond haemodialysis, hemofiltration and haemodiafiltration, using chemical engineering and biomedical engineering skills. 62 Returning to the body of the specification, in a little under two pages (on pages 1a to 3) the background to the invention is provided. The background is primarily directed to haemodialysis, haemofiltration and haemodiafiltration. A short description is given of each procedure. Then a description is given of the preparation of the fluid for these procedures, which is to be understood in the context of the techniques described above before the Priority Date: Different types of control systems are normally used for hemodialysis, hemodiafiltration and hemofiltration operations, respectively. However, they all have in common that at least one concentrate fluid is mixed with pure water in order to produce either the dialysis fluid in connection with hemodialysis operations, or the replacement fluids in connection with hemodiafiltration and hemofiltration operations. Normally, the concentrate to be mixed with water is prepared in centralized preparation plants and is then transferred to the point of treatment in large kegs or other containers. Alternatively, the concentrate may be prepared directly on the spot in large tanks or the like before the treatment is to be started. Thus, in either instance, the concentrate to be used in the medical treatment is prepared in the form of a solution prior to actual use in connection with the medical treatment. At the time of treatment, the concentrate solution is then mixed with water to provide the desired prepared solution for the particular medical treatment. 63 This paragraph can be seen to distinguish between the preparation of the concentrate before use (whether away from the site of treatment or at the site of treatment) and the mixing of the concentrate with water at the time of treatment. 64 The next paragraph, amongst other references to the prior patented art, makes reference to a United States patent (No 4,158,034) which showed how concentrate solutions prepared beforehand can be mixed on-line for the preparation of suitable dialysis solution. Those familiar with the prior techniques of haemodialysis, haemofiltration and haemodiafiltration would be well familiar with the various machines described in the evidence which mixed, on-line, one or two concentrates (previously prepared in volume for a treatment) with water to produce solutions for the three procedures. 65 The last paragraph of this section of the body of the specification describing the background to the invention describes the prior art problems. Two problems are identified: the instability of "certain concentrates" by a proneness to precipitation; and the susceptibility of "certain concentrates" to bacterial growth. These problems are identified as arising when concentrate is prepared prior to its utilisation. Those familiar with the prior techniques of haemodialysis, haemofiltration and haemodiafiltration would understand that these were two problems which beset the production of the B concentrate in advance of use. The specification does not expressly identify the other disadvantages of the prior art described by Ms Yuill. (See [38] above.) 66 In the consistory clauses under the heading "Summary of the Invention", there are descriptions of five systems and one article. Broadly, but not precisely because of the amendments to the claims, the five systems reflect claims 1 to 5 later defined, and the article deals with the cartridge claimed in claims 80 to 85 and 87 later defined. 67 The first system is described as follows (see pages 3 to 4 of the specification): The present invention provides a system for preparing a fluid for a medical procedure by mixing of at least one concentrate in powder form with water, said system comprising: a source of water; a vessel for containing a concentrate in powder form; first fluid conducting means having a first end communicating with said source of water for withdrawing water from said source of water, and a second end for delivering a prepared solution; second fluid conducting means communicating with said source of water with an inlet of said vessel for introducing water from said source of water into said vessel to produce a concentrate fluid containing dissolved powder concentrate in water; third fluid conducting means communicating with an outlet of said vessel and with a mixing point in said first fluid conducting means intermediate said first and second ends for conducting said concentrate fluid from said vessel into said first fluid conducting means to be mixed with fluid being conducted through said first fluid conducting means to thereby produce a prepared solution in said first fluid conducting means for delivery to said second end of said first fluid conducting means; measuring means in said first fluid conducting means downstream of said mixing point for measuring the composition of the prepared solution obtained by mixing of said concentrate fluid and water in said first fluid conducting means; and flow regulating means in said third fluid conducting means responsive to said measuring means for controlling the flow of said concentrate fluid from said vessel. 68 Before setting out the other summaries, it is convenient to refer to one of the drawings in order to explain the terminology used, which is also used in the body of the claims later defined. Figure 1. is included at the end of these reasons among figures 1 to 8 in the Patent. 69 Schematically, one sees the source of water (2), the vessel containing concentrate powder (10), the first fluid conducting means (1) from the water source (2) to the end carrying the prepared solution at the outlet (17), the second fluid conducting means (8) leading into the vessel (11) and the third fluid conducting means (also 8) leading from the vessel (11) to the mixing point (7). 70 The second system is similar but incorporates a second concentrate (a fluid) for mixture at a second mixing point. The summary was in the following terms on pages 4 and 5 of the specification. I have noted the differences from the first system by emphasis and notation. The present invention also provides a system for preparing a fluid for a medical procedure by mixing of at least one concentrate in powder form with water, said system comprising: a source of water; a vessel for containing a concentrate in powder form; first fluid conducting means having a first end communicating with said source of water for withdrawing water from said source of water, and a second end for delivering a prepared fluid; second fluid conducting means communicating with said source of water and with an inlet of said vessel for introducing water withdrawn from said source of water into said vessel to produce a first concentrate fluid containing dissolved powder concentrate in water; third fluid conducting means communicating with an outlet of said vessel and with a first mixing point in said first fluid conducting means intermediate said first and second ends for conducting said first concentrate fluid from said vessel into said first fluid conducting means to be mixed with fluid being conducted through said first fluid conducting means; [Note excision] a source of second concentrate fluid; fourth fluid conducting means having a first end communicating with said source of second concentrate fluid and a second end communicating with said first fluid conducting means at a second mixing point intermediate said first and second ends of said first fluid conducting means for introducing into said first fluid conducting means said second concentrate fluid to be mixed with fluid being conducted through said first fluid conducting means, to thereby produce a prepared solution in said first fluid conducting means downstream of said first and second mixing points for delivery to said second end of said first fluid conducting means, said prepared solution being comprised of said first concentrate fluid and said second concentrate fluid mixed with water withdrawn from said source of water through said first fluid conducting means. [Note excision of measuring means and flow regulating means.] 71 Figure 5 schematically describes such an invention summarised. It is to be noted, however, that conductivity or other measuring devices (14d and 26) are depicted to control the flow of the two concentrates (along 8d to point 7 and along 24 to point 23). 72 The third system summarised on pages 5 and 5a of the specification deals with the preparation of two concentrate fluids formed from mixing two concentrates in powder form in water. 73 The fourth system summarised on pages 5a and 5b of the specification is similar to the first system, the emphasised and excised parts showing the differences: The present invention still further provides a system for preparing a fluid for a medical procedure by mixing of at least one concentrate in powder form with water, said system comprising: a source of water; a vessel for containing a concentrate in powder form, said vessel including an inlet at the top thereof and an outlet at the bottom thereof; first fluid conducting means having a first end communicating with said source of water for withdrawing water from said source of water, and a second end for delivering a prepared solution; second fluid conducting means communicating with said source of water and with said inlet of said vessel for introducing water from said source of water into the top of said vessel to produce a concentrate fluid containing dissolved powder concentrate in water; and third fluid conducting means communicating with said outlet of said vessel and with a mixing point in said first fluid conducting means intermediate said first and second means for conducting said concentrate fluid from the bottom of said vessel into said first fluid conducting means to be mixed with fluid being conducted through said first fluid conducting means to thereby produce a prepared solution in said first fluid conducting means, whereby water is conducted through said vessel from the top thereof to the bottom thereof to thereby maintain a relatively constant concentration level of dissolved powder concentrate in said third fluid conducting means. [Note excision of measuring means and flow regulating means.] 74 The fifth system summarised on pages 5b and 5c of the specification is identical to the first except that the words "a source of water," do not appear at the commencement of the summary. 75 The article summarised on page 5c of the specification provides for a cartridge described as follows: The present invention still further provides a cartridge intended to be used in a system as described above, characterized in that it contains a quantity of powder concentrate suitable for one treatment. With the system and cartridge of the present invention, the solution or fluid for the medical treatment can thus be prepared directly at the point of treatment and substantially at or just prior to treatment beginning. Such a system in accordance with the present invention thus avoids the necessity of preparing large quantities of concentrate solutions in liquid form, which would otherwise result in some of the concomitant problems mentioned above. 76 Some debate took place over the words in the second of these last cited paragraphs. The respondent, and at least one of its witnesses, said that they reveal that the invention can be used to make batches of concentrate before treatment. The respondent submitted that the language in this last paragraph only points to a capability to use the invention for the on-line production of concentrate solution. That capability or facilitative element was not mandatory and did not oust other capabilities. The language of "preparation substantially at or just prior to treatment beginning" was, it was said, redolent of the on-site batch preparation of B solution in the early 1980s before the uses of commercially obtained pre-prepared B solutions. I will come to the context of this in due course; but it is sufficient to say at this point that, armed with an understanding of the prior art of haemodialysis and related procedures, and in the context of the whole of the specification, these passages are not referring to the preparation of a batch for storage, but to preparation contemporaneously on-line: spatially ("directly at the point of treatment") and temporally ("at or just prior to treatment beginning") close or proximate. The phrase "just prior to" is literally correct, but in its context it means production at the same time, practically, as treatment. What is taught by the patent is contemporaneous on-line production. 77 The eight drawing appearing in the specification are summarised as follows: FIGS. 1-4 illustrates four alternative embodiments of the system in accordance with the present invention for preparing a fluid for a medical procedure by mixing of a concentrate in powder form with water. FIG. 5 illustrates a further alternative arrangement for the system of the present invention in which the fluid is prepared starting with one concentrate in powder form and a second concentrate in liquid form. FIG. 6 illustrates a still further arrangement for the system in accordance with the present invention which again utilizes a concentrate in powder form and a concentrate in liquid form, the system of FIG. 6 being particularly adapted for use in connection with a hemodialysis-type of treatment. FIG. 7 illustrates a cartridge intended to be used in any of the alternative system arrangements shown in FIGS 1-6, the cartridge being shown mounted in a holder therefor. FIG. 8 illustrates a still further arrangement for the system in accordance with the present invention in which two different concentrates in powder form are utilized in connection with a further concentrate in liquid form for preparing a fluid for a medical procedure. 78 It is to be noted that figure 6 is said to be particularly adapted for "hemodialysis-type of treatment". I will return to this in due course. 79 There then follow twenty pages of the preferred embodiments of the invention described by reference to the drawings. The particular application to haemodialysis operations is seen in the first two paragraphs of this part of the specifications on page 7: Referring now to the drawings, wherein like reference characters represent like elements, there is shown various alternative arrangements for systems in accordance with the present invention for preparing a fluid for a medical procedure by mixing of at least one concentrate in powder form with water. As the system of the present invention is intended, in particular, for the preparation of dialysis fluids for hemodialysis operations, the system will be described mainly with reference to such an operation. However, it will be appreciated by those skilled in the art that, with minor modifications, the system of the present invention may also be used for the preparation of replacement fluids used in connection with hemofiltration and/or hemodiafiltration operations as well. Still further, to those skilled in the art, it will be apparent that the system in accordance with the present invention can also be used in connection with other medical treatments or procedures. In connection with hemodialysis operations, the dialysis fluid in accordance with the present invention (as well as replacement fluids for hemodiafiltration and hemofiltration operations) typically may comprise a purified solution containing bicarbonate, such as sodium bicarbonate, together with salt compound such as sodium chloride or, optionally, other alkali or other alkali earth chlorides. With such dialysis solutions containing bicarbonate, there is a risk of precipitation of the bicarbonate, particularly, in such instances where the dialysis fluid with bicarbonate is prepared at central processing plants or in large quantities at a treatment facility. The system in accordance with the present invention minimizes such problems of precipitation and/or risk of bacteria growth by preparing the fluid for medical treatment by mixing of at least one concentrate in powder form with water substantially at the time of treatment. 80 The first of these two paragraphs last quoted contains another example of the specification that could be seen to be speaking to those skilled in an art broader than haemodialysis, haemofiltration and haemodiafiltration; in particular, the person familiar with the preparation of fluids, dissolution principles, fluid dynamics and the like, the province, it was submitted by the respondent, of the chemical engineer and the biomedical engineer. 81 The last sentence of the above paragraphs reinforces the proposition put by the applicants, correctly in my view, that the Patent is directing the person aware of the prior art and understanding the problems within the prior art to on-line or contemporaneous production. This is reinforced elsewhere in the specification. For instance, on page 8 of the specification, after a description of the first fluid conducting means of figure 1, there is a reference to the prior art and "the previously prepared liquid concentrate" being introduced into the main conduit. 82 The description of the preferred embodiments first deals with figures 1 to 4 on pages 7 to 12 of the specification. 83 On page 12 of the specification in the discussion of the preferred embodiments by reference to the drawings there is introduced the notions of "top" and "bottom" which are important to some of the claims. The following paragraph appears: Further, in accordance with the preferred embodiments of the present invention, it is to be noted that water is introduced into the concentrate powder column 10 at the top of the column 10 and conducted downwardly to the bottom thereof. This is preferably in order to maintain and provide a relatively constant concentration level of dissolved powder concentrate into the primary fluid line 1. However, it should also be appreciated that water withdrawn into the concentrate fluid line 8 could be conducted through the powder column 10 from the bottom toward the top, both in connection with normal operation as well as in connection with initial priming of the system. [emphasis added] 84 This paragraph can be seen (and the respondent places some reliance on this) to contain two ideas well understood to those familiar with chemical engineering: first, percolation – the dissolution of dry or solid solute by the downward flow of water over and through a bed or column or arrangement of the solute; and secondly, the use of a fluidised bed by introducing water from the bottom and moving it towards the top of the bed. 85 The specification also deals on page 12 of the specification with access to the source of water: Still further, it should be appreciated that the primary fluid line 1 and concentrate fluid line 8 could both be connected directly to a source of water such as a tap water system, for example, by means of a T-coupling, instead of to a reservoir which is supplied with water. Furthermore, it should also be appreciated that the primary fluid line 1 and concentrate fluid line 8 could be connected to different sources of water, although it is preferable that they both be connected to a common source of water such as a reservoir 2 as shown in FIGS. 1-4. 86 This passage is relevant to an argument of the respondent concerning the meaning of the claims and the access to the water supply. 87 The description of the preferred embodiments then proceeds to deal with figure 5 and the use of a liquid concentrate as well as a powder. Though it is figure 6 which is said to be "particularly" intended for use in connection with a haemodialysis-type operation, a person familiar with the prior art and conduct of haemodialysis and related procedures would appreciate in the following discussion by reference to figure 5, the stable liquid as A concentrate and the powder as B concentrate: In certain instances, the solution for a medical procedure or treatment is to be prepared from more than one concentrate, such as, for example, the dialysis solution disclosed in the aforementioned European patent specification EP-B1-0 022 922. In such situations, in accordance with the present invention, the more stable concentrate may be provided in a liquid form and the less stable concentrate or concentrates provided in powder form. In this regard, FIG. 5 illustrates a modified system in accordance with the present invention for preparing a solution for a medical procedure or treatment in which the solution is prepared from one concentrate in powder form and one concentrate in liquid form. Again, in FIG 5, the same reference characters have been used as in the remaining figures, but with the added letter "d" being used to designate modified components. In accordance with the modified system shown in FIG. 5, a suitable reservoir 2 is provided from which fluid for preparing a solution is conducted, on the one hand, via a main or primary conduit 1 and, on the other hand, through a concentrate circuit or conduit 8d containing a powder concentrate column 10d there-in. The concentrate conduit 8d communicates with the main conduit 1 at a mixing point 7. Means for regulating the flow of fluid in the main conduit 1 and for deaeration, respectively, have been indicated by a single rectangle marked 3d, 5d, 6d. A conductivity meter or other measuring device is provided in the main conduit 1, as indicated by the reference numeral 14d. The conductivity meter or other measuring device 14d is adapted to control a flow regulating device 13d provided in the concentrate conduit 8d downstream of the powder concentrate column 10d. If the flow regulating device 13d comprises a throttle, such throttle 13 shown in FIG 1, the throttle device 3d should be located upstream of the mixing point 7. It will thus be appreciated that the foregoing description of the system according to FIG. 5 substantially corresponds with the systems described hereinabove with reference to FIGS. 1-4. In the system of FIG. 5, however, a second mixing point 23 is provided downstream of the conductivity meter 14d. At mixing point 23, a second concentrate fluid is introduced into the main duct via a second concentrate conduit or duct 24 which communicates with a source of second concentrate 25, which, in this instance, is in a Liquid form. The flow of concentrate through the second concentrate duct 24 is regulated with the aid of a conductivity meter or other measuring device 26 provided in the main conduit 1 and which controls a flow regulating device 27 provided in the second concentrate duct 24. For ultimate monitoring of the prepared solution, a pH meter 28 may be installed in the main conduit 1. If conductivity, pH, temperature, or any other parameter utilized for controlling the flow of concentrates through their respective conduits 8d, 24 do not agree or correspond with the desired value, the prepared fluid is passed via a bypass valve 29 directly to a discharge (not shown). If, on the other hand, all the parameters are correct or in accordance with their desired values, the prepared solution is passed via a valve 30 to the actual point of treatment, for example, a dialyzer. Thus, it will be appreciated that if two concentratets [sic] are to be conducted to the main duct 1 at two separate mixing points 7, 23 in the main conduit 1 for mixing with the fluid being conducted through the main conduit 1, conductivity meters or other measuring devices 14d, 26 for accurate monitoring of the composition of the prepared solution upstream as well as down stream of the second mixing point 23 may appropriately be arranged in the main duct 1 and, in particular, arranged downstream of the respective mixing points 7 with which the concentrate conduit 8d communicates. 88 A number of matters should be noted about these passages. First, there is reference again to a "conductivity meter or other measuring device" adapted to control a flow regulating device for both concentrates. It is not to be forgotten, however, that in the well known prior art there were existing dialysis machines that used proportioning devices or mechanisms based on volume and not the measurement of conductivity or temperature or some other variable in the fluid line. Secondly, it should be noted that the order of the mixing of the two concentrates is specifically identified by the use of the word "downstream" on three occasions. This is relevant to the question of construction of the Patent and order of mixing to which I will come in dealing with infringement. 89 The description of the preferred embodiments then proceeds on pages 14 and 15 of the specification to deal with figure 6, directed particularly, as I have said, to haemodialysis. In this configuration, the entry points of the concentrates have been reversed (the liquid A, first, and the concentrate solution from dissolved powder, B, second). Once again, pumps controlled by conductivity meters are referred to. The description includes the following: FIG. 6 shows a still further modified system in accordance with the principles of the present invention which is particularly intended for use in connection with preparation of a dialysis fluid for use in connection with a hemodialysis operation. Once again, the same reference characters have been used to designate like components, with the added character "e" being included with respect to modified components. The system shown in FIG. 6 is similar to that in accordance with FIG. 5 in that it is used to prepare a solution from two different concentrates, one in liquid form and one in powder form. The system of FIG. 6 differs from FIG 5, however, with respect to the Location the concentrate fluids obtained from the Liquid and powder sources are introduced into the main duct or conduit 1. In accordance with the system of FIG. 6, water for use in preparing the dialysis fluid is introduced to a heating vessel or reservoir 2 for heating the water to the desired temperature. From the heating vessel or reservoir 2, the main part of the water used in preparing the dialysis fluid is conducted from the reservoir 2 through a main or primary conduit 1. In the main conduit 1, the flow is degassed by means of a throttle 3e and, a pump 5e and a deaerator 6e, shown together in FIG. 6 as a single rectangle. A liquid concentrate line or duct 24e communicates with the main conduit 1 at a mixing point 23e downstream of the throttle 3e and the rectangle 5e, 6e. The concentrate duct 24e includes a concentrate pump 27e therein which pumps a liquid concentrate from a liquid concentrate container 25e. The conductivity of the mixture after introduction of the liquid concentrate is measured in the main conduit 1 by means of a conductivity meter 26e which controls the pump 27e. A smaller portion of the water in the reservoir 2 is fed through a concentrate fluid circuit comprised of a concentrate conduit 8e. A column or vessel 10 containing a concentrate in powder form is provided in the concentrate conduit 8e so that, as with the other embodiments discussed hereinabove, the smaller portion of water withdrawn from the reservoir 2 is fed through the column 10 from the top toward the bottom thereof, and from there through a continuation of the concentrate conduit 8e to a concentrate pump 13e. From the pump 13e, the concentrate fluid obtained from the vessel 10 is then conducted to the main conduit 1 at a mixing point 7e where it is mixed with the main flow of water from the reservoir 2, which includes the liquid concentrate therein. The conductivity is thereafter measured once again, utlizing the conductivity meter 14e which controls the pump 13e in the concentrate conduit 8e. 90 The description also goes on to describe (on page 15 of the specification) the ultimate fail safe monitoring and diversion of the fluid if it departs from the relevant parameters. 91 Also, there is a description on pages 15 to 17 of the specification of the somewhat more complex body of schematic piping and equipment on the left hand side of figure 6 between the vessel (10) and the pump for the liquid (27e). This piping and equipment is for priming and sterilisation. It would be understood by the reader familiar with the prior art and its application that haemofiltration and haemodiafiltration involve the delivery (and not return) of fluid (referred to in the patent as "replacement fluid") to the body, venously or arterially and thus the need for such fluid to be sterile. 92 The respondent sought to take some comfort from the fact that figure 6, particularly directed to haemodialysis operations, mixes the A, (liquid) concentrate first, upstream of the B concentrate created from the dissolution of powder by the invention. No particular advantage for dialysis is described in the specification from this order of mixing. The prior art machines had both arrangements. I will return to this in discussing infringement. It suffices at this point to note that the priming and disinfecting attributes would also make figure 6 "particularly adapted for use in connection with haemodialysis – type of treatment". 93 The description of the preferred embodiments then deals on pages 17 and 18 of the specification with the use of the cartridge, by reference in particular to figure 7. Whilst it is of course necessary to remember that this is not the body of claims, the following should be noted about the cartridge there appearing: the cartridge is "totally closed", it has membranes at the upper inlet and lower outlet adapted to be penetrated by connection devices at the ends of the fluid circuit (in and out) and information about desirable particle size is given to obtain a uniform solution. The following appears at pages 17 and 18 of the specification. Further in accordance with the present invention, the powder concentrate columns or vessels 10 utilized in the various embodiments described hereinabove may conveniently be in the form of a self-contained cartridge containing a quantity of powder concentrate therein suitable for one treatment procedure, the cartridge being totally closed and provided with penetrable membranes at its upper inlet and its lower outlet which are adapted to be penetrated by suitable connection devices for the ends of the conduit in the fluid concentrate circuit 8 or 8d or 8e. Also, preferably, [sic] the cartridge is internally sterile, such as by having been exposed to radiation such as gamma radiation. Fig. 7 shows such a cartridge 10f, as well as a holder 43 therefor, which is specifically constructed to accommodate a cartridge of a particular configuration. As shown in FIG. 7, the cartridge column 10f comprises a closed vessel provided with penetrable membranes 62, 64 at its upper inlet end and its lower outlet end, respectively. Within the cartridge vessel, there is provided a supply of powder concentrate of sufficient quantity so as to be suitable for a single treatment. For instance, in connection with preparation of a dialysis fluid or solution, the concentrate in powder form may consist of sodium bicarbonate material, and the quantity thereof contained in the cartridge would be on the order of magnitude of 400-900 grams and, more preferably, approximately 600 grams. Also, the contents of the cartridge 10f are preferably sterilized, such as by means of gamma radiation. Further, in order to obtain an even flow of fluid through the powder concentrate vessel or column 10f and, thus, a uniform solution of the powder in the fluid, it has been found that there is a preferable minimum particle size for the powder concentrate. For many materials, and especially bicarbonate materials, it has been found that the particles of powder should be of a size of at least 100 microns ( µ ), and preferably larger than 150 microns ( µ ). A minor blending in of smaller particles may, however, be acceptable. In this regards, a suitable mixture, for example, may be comprised of powder particles having a size of between 130 and 500 microns ( µ ). The cartridge 10f is adapted to be mounted in a holder 43 provided with a pair of upper and lower swinging arms 44 and 45 mounted on a suitable support structure 60. The arms 44, 45 are provided with spike connectors 46 and 47, respectively, which are intended to penetrate the membranes 62, 64 at the upper inlet and the lower outlet of the cartridge vessel 10f. In this regards, the upper inlet and lower outlet of the cartridge 10f are each provided with an outwardly protruding nipple having the penetrable membranes 62, 64 therein, which nipples are adapted to be received in suitable recesses in the arms 44, 45 so that the end of the spike connectors 46, 47 may penetrate same when the arms 44, 45 are swung into essentially horizontal positions to hold the cartridge 10f. In this regards, the spacing between the arms 44, 45 is such as to correspond to the height of the cartridge 10f. The upper or inlet spike 46 is intended to be connected to the conduit in the concentrate fluid circuit 8e which is upstream of the cartridge 10 as shown in FIG. 6, whereas the outlet spike 47 is intended to be attached to the concentrate conduit which is downstream of the cartridge 10 in the fluid concentrate circuit 8e. It will thus be appreciated that connection of the cartridge 10f in the circuit 8e is accomplished relatively easily by moving the arms 44, 45 apart, positioning the cartridge 10f therebetween and then moving the arms 44, 45 into horizontal, parallel, positions so that the spikes 46, 47 penetrate the membranes 62, 64. 94 The respondent emphasised, in connection with understanding the meaning of the word "cartridge" as used in the claims, the importance of the adaption or fitting of the vessel into a space with the surrounding configuration – to produce a satisfactory and integral "fit". 95 The description of the preferred embodiments then at pages 19 to 21 of the specification deals with the mixture of two powders, by reference to figure 8. (The two powders are identified in figure 8 as sodium bicarbonate and sodium chloride.) Those familiar with the prior art and operation of haemodialysis and related procedures before the Priority Date would understand that sodium chloride is sometimes within the A concentrate and sometimes not. It is unnecessary to set out much of the detailed description of the operation of figure 8. It is sufficient to note, however, that figure 8 reveals, and the description of the preferred embodiment provides for, the acid, or A concentrate, being mixed (at 53) upstream of the concentrates derived from the powders (at 23g and 7g). Once again, at least this time for the concentrates derived from powder, conductivity meters are used to control the flow to the mixing points. This part of the description of the preferred embodiment contains material relied upon (at least initially) by the respondent to the effect that the Patent is not only directed to on-line production for delivery, but also is directed to batch production. The following appears on pages 21 and 22 of the specification: By way of example, for preparation of a dialysis fluid, the cartridge 10g1 may contain a bicarbonate material in powder form, such as sodium bicarbonate, whereas the cartridge 10g2 may contain a different concentrate powder form, such as sodium chloride powder. In this instance, the quantity of sodium bicarbonate in cartridge 10g1 may be on the order of 400-900 grams and, more preferably, approximately 600 grams, whereas the quantity of sodium chloride in the cartridge 10g2 would preferably be on the order of 1,000-3,000 grams and, more preferably, 1,300-2,700 grams and, still more preferably, approximately 1,400 grams. Such cartridges 10g1 and 10g2 for use in connection with preparation of a dialysis fluid, i.e., a cartridge 10g1 containing bicarbonate material and a cartridge 10g2 containing sodium chloride material, both in powder form, may also be used in practice, together with a liquid concentrate 50 which contains other substances necessary for the treatment, such as, for example, acid, calcium, potassium, magnesium, glucose, or the like. A suitable composition for the liquid concentrate 50, for example, may be as follows: CH3C00H 44.17 g KC1 36.54 g CaCl2 + 6H20 93.94 g HgCl2 + 6H20 24.92 g H20 210 g ----------------------------------------- Total approx. 410 g The quantities provided in the example hereinabove correspond to that necessary for one treatment operation or procedure, with the quantity of water being determined so that no precipitation should be able to occur during storage at refrigerating cabinet temperature. With a smaller quantity of water, there is a risk of precipitation. In the example above, it will be appreciated that instead of acidic acid, other acids could be used, such as, for example, hydrochloric acid or citric acid. [emphasis added] 96 Reliance was initially placed by the respondent on the word "storage". Though not made clear by the balance of the evidence, from reading this part of the specification, the "storage" there referred to is of the A solution. This part of the specification is not of any real assistance to the respondent in the manner initially asserted. In final submissions the respondent withdrew this submission, recognising that the "storage" being referred to was of the A solution. 97 Finally in this section of the specification, the various embodiments are summarised by reference to the base numbers in the drawings; and the description concludes with a paragraph of the kind dealt with by the High Court in Welch Perrin & Co Pty Ltd v Worrel (1961) 106 CLR 588, 614. The following appears at pages 24 to 26 of the specification: It will thus be apparent from the foregoing description that the present invention provides a system for preparing a fluid intended for a medical procedure by mixing of at least one concentrate in a powder form. The system in accordance with the present invention comprises a reservoir 2 for a source of water, and at least one vessel 10 for containing a concentrate in powder form, and a fluid conducting circuit 8 for withdrawing a small quantity of water from the reservoir 2 and passing same through the vessel 10 containing the concentrate in powder form in order to dissolve the concentrate before it is mixed with the rest of the water withdrawn from the reservoir 2 through a main or primary fluid conducting means 1 downstream of the liquid containing reservoir 2. In accordance with one aspect of the present invention, measuring means 14 are provided in the primary fluid conduit means 1 downstream of the mixing point 7 for measuring the composition of the prepared solution obtained by mixing of the produced concentrate fluid in the concentrate fluid circuit 8 with water being conducted through the primary conduit 1, and flow regulating means 13 provided in the concentrate fluid circuit 8 downstream of the concentrate vessel 10 which is responsive to the measuring means 13 for controlling the flow of concentrate fluid from the vessel 10. In accordance with a further aspect of the present invention, a source of second concentrate fluid 25, 10g2 is provided as well, and fluid conducting means 24 are provided for introducing the second concentrate fluid into the primary fluid conducting means 1 at a second mixing point 23 therein to be mixed with the fluid being conducted therethrough to thereby produce a prepared solution downstream of the two mixing points, 7, 23, the prepared solution being comprised of a mixture of water with a first concentrate fluid produced by conducting water from the reservoir 2 in the vessel 10, 10g1 containing the concentrate in powder form and a second concentrate fluid from the source 25, 10g2 thereof. In one embodiment of the present invention, the source of second concentrate fluid comprises a concentrate in liquid form 25, wheras [sic], in a further embodiment of the present invention, the second concentrate fluid is produced by conducing water from the reservoir 2 through a second vessel 10g2 containing powdered concentrate therein to dissolve the second powdered concentrate in the water to produce the second concentrate fluid. In accordance with a still further aspect of the present invention, the vessel 10 containing the concentrate in powder form therein includes an inlet at the top thereof and an outlet of the bottom thereof, with the vessel 10 being arranged in the concentrate fluid circuit & so that water withdrawn from the reservoir 2 is introduced into the top of the vessel 10 to produce a concentrate fluid containing dissolved powder concentrate therein, and so that the concentrate fluid is withdrawn from the bottom of the vessel 10 and conducted to the primary fluid conducting means 1 to be mixed with water being conducted therethrough. In this manner, water is conducted through the powder concentrate vessel 10 from the top thereof to the bottom thereof to thereby maintain and provide a relatively constant concentration level of dissolved powder concentrate. Conveniently, the powder concentrate vessel 10 may comprise a normally completely closed cartridge 10f, having penetrable membranes 62, 64 at its inlet and outlet outlets which are adapted to be penetrated upon being connected to the concentrate fluid circuit 8. The cartridge 10f contains a quantity of powder concentrate therein suitable for one treatment procedure. In this manner, for different treatment operations, it is only necessary to connect new cartridges 10 and/or other sources 25, 50 of liquid concentrate to the system, with the remaining components of the system being reusable for different medical procedures or treatments. As will be readily apparent to those skilled in the art, the present invention may be used in other specific forms without departing from its spirit or essential characteristics. For example, the components included in the system may be varied within wide limits, both with regard to their form and their function. Furthermore, it will be apparent to those versed in the art that the system of the present invention can readily be modified by combinations of one or more powder concentrates, either alone or in further combination with one or more liquid concentrates, for producing a desired prepared solution for a medical procedure or treatment. The preferred embodiments described hereinabove are therefore to be considered as illustrative and not restrictive, the scope of the invention being indicated by the claims rather than the foregoing description, and all changes which come within the meaning or range of equivalents of the claims are therefor intended to be embraced therein. 98 The respondent emphasised the width of the invention and its field – a system for preparing a fluid directed to a medical procedure. The last paragraph quoted above was relied upon by the respondent in emphasising this width of field and, concomitantly, the width and depth of skill of the skilled addressee. 99 The applicants emphasised the elucidation of "top" and "bottom" in the second last paragraph quoted above – the top is at or above the powder column and the bottom is the place at the bottom of the powder column where the fluid is withdrawn. the claims 100 The complaints in the variously amended application and statement of claim concern claims 2, 4, 5, 11, 24, 25, 28, 35, 80, 81 and 88 of the Patent. In the light of arguments on infringement and on the cross-claim, it is appropriate to set out those claims together with claims 1, 3, 6, 7, 8, 9, 10 and 50 to 55. THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. A system for preparing a dialysis or replacement fluid or a component fluid thereof by mixing of at least one concentrate in powder form with water, said system comprising: a source of water; a vessel containing a powder concentrate; first fluid conducting means having a first end communicating with said source of water for withdrawing water from said source of water, and a second end for delivering a prepared dialysis or replacement fluid or component fluid thereof; second fluid conducting means communicating with said source of water and with an inlet of said vessel for introducing water from said source of water into said vessel to thereby produce a concentrate solution containing dissolved powder concentrate in water; third fluid conducting means communicating with an outlet of said vessel and with a mixing point located in said first fluid conducting means intermediate said first and second ends for conducting said concentrate solution from said vessel into said first fluid conducting means where it is mixed with fluid being conducted through said first fluid conducting means to thereby produce the prepared fluid in said first fluid conducting means; measuring means located in said first fluid conducting means downstream of said mixing point for measuring the composition of the prepared fluid; and flow regulating means located in said third fluid conducting means and being responsive to said measuring means for controlling the flow of said concentrate solution from said vessel. 2. A system for preparing a dialysis or replacement fluid or a component fluid thereof by mixing of at least one concentrate in powder form with water, said system comprising: a source of water; a vessel containing a powder concentrate; first fluid conducting means having a first end communicating with said source of water from said source of water, and a second end for delivering a prepared fluid for use in a hemodialysis, hemofiltration or hemodiafiltration procedure; second fluid conducting means communicating with said source of water and with an inlet of said vessel for introducing water withdrawn from said source of water into said vessel to thereby produce a first concentrate solution containing dissolved powder concentrate in water; third fluid conducting means communicating with an outlet of said vessel and with a first mixing point located in said first fluid conducting means intermediate said first and second ends for conducting said first concentrate solution from said vessel into said first fluid conducting means where it is mixed with fluid being conducted through said first fluid conducting means; a source of second concentrate solution; and fourth fluid conducting means having a first end communicating with said source of second concentrate solution for withdrawing second concentrate solution from said source of second concentrate solution, and a second end communicating with a second mixing point located intermediate said first and second ends of said first fluid conducting means for introducing said second concentrate solution into said first fluid conducting where it is mixed with fluid being conducted through said first fluid conducting means to thereby produce the prepared fluid in said first fluid conducting means downstream of said first and second mixing points, said prepared fluid being comprised of said first concentrate solution, said second concentrate solution and water withdrawn from said source of water through said first fluid conducting means. 3. A system for preparing a dialysis or replacement fluid or a component fluid thereof by mixing of at least two concentrates in powder form with water, said system comprising: a source of water; a first vessel containing a powder concentrate; a second vessel containing a second powder concentrate different from said first powder concentrate; first fluid conducting means having a first end communicating with said source of water for withdrawing water from said source of water, and a second end for delivering a prepared dialysis or replacement fluid or component fluid thereof; a concentrate solution circuit communicating with said source of water and with said first fluid conducting means, said concentrate solution circuit including first connection means at a first location in said concentrate solution circuit for connecting said first vessel to said concentrate solution circuit so as to introduce water from said source of water into said first vessel to dissolve said first powder concentrate and to withdraw a first concentrate solution containing said dissolved first powder concentrate from said first vessel, and second connection means at a second, different location in said concentrate solution circuit for connecting said second vessel to said concentrate solution circuit so as to introduce water from said source of water into said second vessel to dissolve said second powder concentrate and to withdraw a second concentrate solution containing said dissolved second powder concentrate from said second vessel, said first and second connection means being different from one another so that said first vessel is only connectable at said first location in said concentrate solution circuit and said second vessel is only connectable at said second, different location in said concentrate solution circuit, said concentrate solution circuit being arranged for conducting and delivering said first and second concentrate solutions into said first fluid conducting means at a location intermediate of said first and said second ends of said first fluid conducting means where they are mixed with fluid being conducted through said first fluid conducting means to thereby produce the prepared fluid being comprised of solutions from said concentrate solution circuit and water withdrawn from said source of water. 4. A system for preparing a dialysis or replacement fluid or a component fluid thereof by mixing of at least on concentrate in powder form with water, said system comprising: a source of water; a vessel containing a powder concentrate, said vessel including an inlet at the top thereof and an outlet at the bottom thereof; first fluid conducting means having a first end communicating with said source of water for withdrawing water from said source of water, and a second end for delivering a prepared fluid; second fluid conducting means communicating with said source of water and with said inlet of said vessel for introducing water from said source of water into the top of said vessel, whereby a concentrate solution containing dissolved powder concentrate in water is produced in the vessel; and third fluid conducting means communicating said outlet of said vessel with a mixing point located in said first fluid conducting means intermediate said first and second ends for conducting said concentrate solution from the bottom of said vessel into said first fluid conducting means to thereby produce the prepared fluid, wherein the system is arranged such that a relatively constant concentration level of dissolved powder concentrate is maintained in said third fluid conducting means by fluid being conducted through said vessel from its top to its bottom. 5. The system of claim 1, 2, 3 or 4 wherein said source of water comprises a reservoir for containing water. 6. The system of claim 5, when appended to claim 1, wherein said measuring means comprises a conductivity measuring device. 7. The system of claim 5, when appended to claim 1, wherein said flow regulating means comprises a throttling device. 8. The system of claim 7 further including a suction pump arranged in said first fluid conducting means downstream of said mixing point for conducting water from said reservoir through said first fluid conducting means and for conducting water from said reservoir through said second and third fluid conducting means. 9. The system of claim 8 further including a throttling device arranged in said first fluid conducting means intermediate said reservoir and said mixing point, and further including a deaerating device arranged in said first fluid conducting means downstream of said suction pump. 10. The system of claim 1 wherein said flow regulating means comprises a suction pump. 11. The system of claim 1 or 2 wherein said inlet of said vessel is at the top thereof and said outlet of said vessel is at the bottom thereof so that water is conducted through said vessel from the top thereof to the bottom thereof whereby a relatively constant concentration level of dissolved powder concentrate is maintained in said third fluid conducting means. … 24. The system of claim 1, 2 or 4 wherein the powder concentrate has a particle size which is greater than 100 microns. 25. The system of claim 24 wherein said powder concentrate comprises a bicarbonate material having a particle size between 130 and 500 microns. … 28. The system of claim 1, 2 or 4 wherein said vessel comprises a self-contained cartridge containing a quantity of said powder concentrate suitable for one treatment procedure. … 35. The system of claim 28 wherein said powder concentrate in said cartridge comprises bicarbonate material, the quantity of said bicarbonate material in said cartridge being of the order of 400 to 900 grams. … 50. The system of claim 2 further including first and second measuring means in said first fluid conducting means, said first measuring means being downstream of said first mixing point and operative to measure the composition of fluid in said first fluid conducting means downstream of said first mixing point and said second measuring means being downstream of said second mixing point and operative to measure the composition of fluid in said first fluid conducting means downstream of said second mixing point. 51. The system of claim 50 further included first flow regulating means responsive to said first measuring means for controlling the flow of said first concentrate solution through said third fluid conducting means, and second flow regulating means responsive to said second measuring means for controlling the flow of said second concentrate solution through said fourth fluid conducting means. 52. The system of claim 51 wherein said first and second flow regulating means each comprise a suction pump. 53. The system of claim 51 further including a throttling device, a suction pump and deaerating device arranged in said first fluid conducting means. 54. The system of claim 53 wherein said throttling device, said suction pump and said deaerating device are all arranged in said first fluid conducting means downstream of said source of water and upstream of both of said first and second mixing points. 55. The system of claim 50 wherein said first and second measuring means each comprise a conductivity measuring device. … 80. A cartridge arranged for use in a system in accordance with any one of the preceding claims, characterised in that the cartridge contains a quantity of said powder concentrate suitable for one treatment. 81. A cartridge as claimed in claim 80 arranged for a dialysis procedure involving the use of at least one concentrate in powder form, wherein the cartridge contains a quantity of the order of magnitude of 400 to 900 grams sodium bicarbonate, preferably approximately 600 grams. … 88. A system according to any one of claims 28 to 30, wherein the powder concentrate is arranged as a column between the inlet and outlet of the cartridge so that, in operation, the powder concentrate becomes dissolved in water flowing through the vessel, and said second fluid conducting means and said cartridge are so dimensioned, as to produce a substantially saturated solution of the powder concentrate in water. 101 The essence of the invention was said to be simple, but real: the idea of dispensing with the ten litre container of pre-mixed concentrate (in particular B concentrate) and using powder on-line in a vessel to create a saturated concentrate solution to be then diluted on-line in the manner that the pre-prepared liquid solution in the prior art was diluted with water (and other concentrate, if necessary) by proportioning machine devices. 102 The applicants emphasised that the claims are not method claims but for a system – the physical set up of the identified objects – tubes, containers and powder concentrate etc, with limitations by result – the suitable preparation of dialysis or replacement fluid or a component fluid thereof. Infringement the alleged infringement 103 The acts of alleged infringement are not in contest and can be described shortly. The respondent has sold, hired or otherwise disposed of, or offered so to do: (a) articles containing 650g and 950g of sodium bicarbonate by reference to the trade mark "biBag" in accordance with the invention claimed in the Patent; (b) machines and modification kits for machines to enable dialysis machines to be used or adapted to perform haemodialysis, haemofiltration and haemodiafiltration producing a concentrate solution made in accordance with the invention in the Patent. 104 Physical examples of the "biBag" with sodium bicarbonate are exhibits EJY4 and TJW 18 and, cut away and empty, are exhibits TJW 17 and TJW 19. 105 Infringement is alleged of claims 2, 4, 5, 11, 24, 25, 28, 35, 80, 81 and 88. 106 The respondent's dialysis machines known as the "Fresenius 4008" and the "Fresenius Online Plus System with biBag Option" are said to infringe. They are the "type 2" and the "type 3" systems the schematic operation of which relevant for these proceedings are agreed and are set out in the following diagrams: 107 A cross-sectional view of the infringing biBag as found in a promotional document of the respondent is as follows: 108 Claim 1 is not alleged to be infringed. Claim 1 contains integers of measuring means and flow regulating means. The Fresenius machines have such, but in different places than described in claim 1. 109 The disputed questions of infringement were limited to those clearly and helpfully argued by counsel. the applicable principles of construction 110 The parties did not debate any question of principle of construction at any length. The relevant principles and closely related principles of infringement are found conveniently, and in some cases, for a first instance judge in this Court, authoritatively, in a number of decisions. I refer, in particular to Populin v HB Nominees Pty Ltd (1982) 59 FLR 37, 41-43; Welch Perrin at 610, Olin Corporation v Super Cartridge Co Pty Ltd (1977) 180 CLR 236, 246; Minnesota Mining & Manufacturing Co v Beiersdorf (Australia) Ltd (1980) 144 CLR 253, 286 (the 3M case), Walker v Alemite Corporation (1933) 49 CLR 643, 656; Radiation Ltd v Galliers and Klaerr Pty Ltd (1938) 60 CLR 36, 51-2; Sunbeam Corporation v Morphy-Richards (Australia) Pty Ltd (1961) 180 CLR 98, 109-110; Rhone-Poulenc Agrochimie SA v AIM Chemical Services Pty Ltd (1986) 12 FCR 477, 496-98; Rehm Pty Ltd v Websters Security Systems (International) Pty Ltd (1988) 81 ALR 79, 91-2; Nicaro Holdings Pty Ltd v Martin Engineering Co (1990) 91 ALR 513, 527-29; Decor Corp Pty Ltd v Dart Industries Inc (1988) 13 IPR 385, 397-400, 410; Flexible Steel Lacing Company v Beltreco Ltd [2000] FCA 890; 49 IPR 331, 347-50. 111 I do not presume to distill these authorities; but it is appropriate to highlight some of the most (if I may respectfully put it) convenient and apt expressions of principle for the purposes of this case. In Populin v HB Nominees Pty Ltd, the Full Court (Bowen CJ, Deane J and Ellicott J), after referring to the need for the patentee to claim only what is essential to the invention, said the following at 41: At the same time, however, the courts have avoided too technical or narrow a construction of claims. In Radiation Ltd v Galliers and Klaerr Pty Ltd (1938) 60 CLR 36 Dixon J said: "But, on a question of infringement, the issue is not whether the words of the claim can be applied with verbal accuracy or felicity to the article or device alleged to infringe. It is whether the substantial idea disclosed by the specification and made the subject of a definite claim has been taken and embodied in the infringing thing" (1938) 60 CLR at p 51. 112 In the 3M case Aickin J, after referring to Clark v Adie (1875) 10 Ch App 667 and the doctrine of "pith and marrow", said at 286: …it remains the law that a defendant may not take the substance of an invention unless the wording of the claims make it clear that the relevant area has been deliberately left outside the claim. 113 The specification and claims must be construed in the position of a person acquainted with the surrounding circumstances of the state of the art and manufacture at the time and, in that sense, through the eyes and mind of someone skilled in the art: Kimberly-Clark Australia Pty Ltd v Arico Trading International Pty Ltd [2001] HCA 8; 207 CLR 1, 16 at [24], Rhone-Poulenc at 496 (per Lockhart J) citing May LJ in Codex Corporation v Raeal-Milgo Ltd [1983] RPC 369, 381; and the specification and claims must be read as a whole recognising the existence and role of its different parts: Welch Perrin at 610; the 3M case at 267; Decor at 400 (rules (1) to (5)) and 410. 114 The interpretation of the specification and claims and the question of the resulting infringement or not is to be undertaken, as a matter of substance, having regard to the essence of the invention: Commonwealth Industrial Gases Ltd v MWA Holdings Pty Ltd (1970) 180 CLR 160, 168; the 3M case at 286; Radiation Ltd v Galliers and Klaerr Pty Ltd at 51; Populin v HB Nominees at 41-2; and Nicaro at 528-29. 115 Before turning to the arguments, it is necessary, in particular for one of the arguments to be discussed (the meaning of the word "comprise"), to say something about an aspect of the reasons of Sheppard J in Decor. His Honour said at 410-11: …if there is disclosed in the specification an intention on the part of the draftsman that words used elsewhere are to have a particular meaning, that meaning must be given those words because the draftsman has used his own dictionary. 116 His Honour was not laying down a rule that once one meaning can be ascribed to a word in the specification, it is to be taken that that is its meaning wherever it appears in the specification. If a dictionary has been created that may be so; but words may bear different meaning in different places depending on context. Claim 2 the word "comprising" 117 It was common ground that the word "comprise" can mean consists of exhaustively, in the sense of constituted exclusively by, and also consists of non-exclusively, in the sense of include. Each side referred me to the comprehensive discussion of the word by Lindgren J in General Clutch Corporation v Sbriggs Pty Ltd (1997) 38 IPR 359, 372-7. 118 The view that the usage of "comprise" as meaning include is an older and somewhat outdated usage is, with respect, somewhat doubtful. Modern dictionaries of English identify both: see the discussion by Lindgren J and see also the Merriam-Webster OnLine dictionary. Ultimately, it is a question of context what it means in any given usage: see also Abbott Laboratories v Corbridge Group Pty Ltd [2000] FCA 1713; and on appeal [2002] FCAFC 314; [2002] AIPC 91-824. 119 It is beyond argument that, in one sense, more things are required to make a working system than are identified as expressed integers of claim 2 – the person familiar with haemodialysis, haemofiltration and haemodiafiltration reading the specification as a whole would naturally understand that to be the case. For example, a pump, a water heater, some fail safe device based on measurement of the ultimate product and deaerators would be recognised by someone familiar with haemodialysis and related procedures as practical and necessary parts of any working system for those treatments. So, the system must be able to be constituted by the integers identified in the claims and other aspects which the skilled reader would understand from the art, as well as from a reading of the specification as a whole. Nevertheless, the patentee has sought to identify in the claims what are the inclusions and exclusions of the boundaries of the respective claimed monopolies. The patentee has identified in the claims the essential integers of each claimed monopoly. The patentee has sought to identify, and so claim, the essence of the invention. Inessential matters, not in the sense of practically irrelevant, but in the sense of essential to the identification of the delimitation of the invention, will be understood by the skilled reader. 120 Thus, at this level of abstraction or generality one can say the word "comprised" is plainly not exhaustive of certain things, but may be exhaustive of others. 121 The real question is whether claim 2 excludes as an integer of the system, certain integers that are included in claim 1: the measuring means and the flow regulating means responsive thereto, such that if such are present in a system, the system is outside the claim for the monopoly of claim 2. It is to be recalled that in the existing art some haemodialysis machines used such devices and some did not. 122 The type 2 and type 3 systems have a conductivity cell (132) and temperature sensor (133) in the third fluid conducting means, and a pump also in the third fluid conducting means. 123 Claim 1 has the two integers of measuring means and flow regulating means, claim 2 does not. Claims 50 to 55 seek to add to claim 2. Claim 50 adds two measuring means located in the first fluid conducting means downstream, respectively, of the two mixing points. Claim 51 builds on claim 50 (and so claim 2) by further including two flow regulating means located in the third and fourth fluid conducting means. Claim 52 narrows claim 51 by identifying the flow regulating means as a pump. Claims 53 and 54 add further devices. Claim 55 narrows claim 50 by identifying the measuring means as a conductivity measuring device. 124 The applicants submitted that the narrowing of claim 1 by the addition of the two integers does not lead to the conclusion that their absence in claim 2 was intended necessarily to exclude their presence whenever there is infringement; rather, it was said, their absence from claim 2 is indicative of a wider claim to monopoly by its boundaries not being confined by the need to have such devices which the prior art taught were not practically necessary. Thereafter, the later claims narrowed or limited the more general claim. Claims 1 and 5 were cited as examples by the applicants. In claim 5, the source of water "comprised" (there meaning, being or constituted by) a reservoir. That did not, it was said, mean that the source of water in claim 1 could not be a reservoir. Rather, as a slightly more limited, or delimited, claim, some prior art might then be avoided. 125 There is force in these submissions. The essence of the invention in the claims (narrowed to a system for the production of fluid for haemodialysis, haemofiltration and haemodiafiltration – "dialysis or replacement fluid or a component fluid thereof") was the use of dry powder in a vessel and its dissolution by the introduction of water into the vessel to produce a saturated (and so constant) concentrate fluid that was then withdrawn from the vessel and then dealt with in the customary way by the relevant machines. 126 It was that essence that was to be claimed and if it was not claimed it was disclaimed. 127 There were, however, many conventional and well known aspects to any system to create a dialysis fluid or replacement fluid or component fluid thereof that were not part of the essence of the invention as claimed, but were necessary for such a system to work. Likewise, there were aspects which were not part of the essence of the invention as claimed and were not necessary for such a system to work, but which could be added to any such system in any particular formulation of the system. On the evidence, a good example of the former was a measuring device to control a fail safe system; and a good example of the latter was a measuring device to control or regulate flow of concentrate into the main line or first fluid conducting means. 128 In the circumstances, the fact that one claim included such devices that were neither practically necessary, nor part of the essence of the invention, would not be likely to lead one to the conclusion that the absence of such devices from another claim was intended to limit that claim to a formulation of the system without such devices. 129 There are textual difficulties, however, in accepting the applicants' submissions. In the body of the specification and in the claims, "comprise" is often used to mean "is constituted by": for examples see page 5 line 13 (and like places), claims 5, 6, 10, 28, 29, 35, 52, 55 and 79. Also, the words "include" and "including" are from time to time used. 130 Also, claim 50 refers to the system of claim 2 "further including" first and second measuring means located as there identified. Likewise claim 51 refers to the system of claim 50 "further including" flow regulating means responsive there to and controlling the flow of concentrate. The phrase "further including" appears to indicate that they were not otherwise included in claim 2. 131 Not without some hesitation, I have come to the conclusion that these textual considerations do not lead to the conclusion that measuring means and the regulating devices were each (or together) integers, which if present meant that claim 2 was not infringed. They are not part of the essence of the invention. They may be claimed and so more particularly limit the claimed monopoly: for example by identifying their placement – see claim 50, or by their technique – see claims 52 and 55. They are, however, part of the well known art concerned with the field beyond the essence of the invention, that is the mixture of concentrate by proportioning machines with fluid which the skilled addressee would know to be either necessary (a measuring device for the fail safe mechanism) or optional (a particular type of measuring device, a particular placement of a measuring device, or a particular flow regulation device, being one based on some measurement device's reading). 132 What is important in claim 2 is that the essence of the invention is there identified. The word "comprise" even given the content of the balance of the specification does not permit the escape from infringement by inclusion of elements, referred to in other claims, which, conformably with the known prior art, are either necessary for, or available to be used in, a working system and which are not part of the essence of the invention revealed in the claims and the specifications as a whole. 133 This does not leave the invention at large. It means that one does not escape infringement by having somewhere in the system for preparation of the fluid or a component thereof one or more of the numerous aspects of the working implementation of the system known by the skilled addressee to be necessary or optional outside what the specification as a whole, and in the knowledge of the prior art, teaches about the essence of the invention. In this sense, the word "comprise" is not exhaustive in claim 2. second fluid conducting means "communicating with" 134 The respondent contends that the second fluid conducting means (H) does not "communicate with" the "said source of water". Rather, in type 2 it "communicates with" the first fluid conducting means (D), and in type 3 with a primary air separator (88c). 135 It was submitted that a common interface was required, so that the source of water opens into the conducting means to form an integral unit. This was said to derive from a dictionary meaning of a "connecting passage". 136 I reject this submission. Read by someone familiar with the prior art, there is communication with the source of water in both cases since there is communication even though for a distance the same tube or pipe can be seen to serve both first and second fluid conducting means or some other function. Professor Schindhelm expressed a similar view in relation to a patent to which I will come in more detail later, the Stasz Patent (see his first affidavit dated 27 December 2001 at [46(7) and (8)]; and in cross-examination at Tpp 270-71 and 276-77). As someone familiar with haemodialysis and related procedures and with techniques involved as at the Priority Date, as well as being familiar with the sciences attending those techniques, Professor Schindhelm saw no need for there to be a direct interface between the source of water and the piping being, and only being, the second fluid conducting means. Similar views can be discerned from Professor Coster's first affidavit (dated 27 December 2001) at [62(9)-(11)] in relation to another cognate patent, the Alza Patent. 137 To the extent that the body of the specification assists in resolving the intended content of the phrase "communicates with", it supports the applicants' approach and the views of Professor Schindhelm. The passages on page 12 of the specification set out at [83] and [85] above support the flexible conception of "communicate with" propounded by the applicants. The availability of utilisation of the body of specification for the purpose is supported by: Kimberly-Clark at 12 [15] and Interlego AG v Toltoys Pty Ltd (1973) 130 CLR 461, 479. The phrase can either be seen to carry some ambiguity or to be read and understood in the light of the body of the specification. the third fluid conducting means communicating with an outlet of said vessel and with a "mixing point located in said first fluid conducting means" intermediate said first and second ends. 138 The respondent submitted that the above element of claim 2 is not satisfied in either type 2 or type 3. In type 2 the mixing point was said not to be in the first fluid conducting means, but in the primary air separator (88c); and in type 3 the mixing point was said to be in a junction (205), not in the first fluid conducting means. 139 I reject this submission. I accept the submission of the applicants that nothing in the claims read in the light of the specification requires that any of the fluid conducting means to be of any particular size or shape or configuration. In the type 2 there is a point in which fluid from the third fluid conducting means mixes with fluid from the first fluid conducting means. The cross-examination of Professor Schindhelm referred to above assists in understanding that an informed and skilled reader would not see the configuration of the primary air separator and junction box as not being part of the first fluid conducting means. first and second mixing points 140 In each of type 2 and type 3 system the A concentrate mixes with the water upstream of the B concentrate entering the first fluid conducting means. The respondent submitted that, properly construed, claim 2 provides for the concentrate from the third fluid conducting means (after dissolution of powder in water: that is the B concentrate) mixing with the water in the first fluid conducting means upstream of or first, before concentrate from the fourth fluid conducting means mixes with the fluid being conducted through the first fluid conducting means, at the second mixing point. The words "first" and "second" were said by the respondent to describe the two mixing points in a sequential fashion – first in time and space (upstream) second in time and space (downstream). 141 I do not so construe the claims, when read in the light of the specification and with what, on the evidence, is the knowledge of a skilled reader about the prior art of haemodialysis and related procedures. 142 The respondent points to the deliberate choice in various embodiments of the points of mixing: see in particular figures 5 and 6. The claims and the specification, however, do not teach the reader that one concentrate fluid is to enter the first fluid conducing means before the other. The words "upstream" and "downstream" are not used in this context, as they are in other places in both the claims and the body of the specification when that meaning is sought to be conveyed. 143 The first concentrate is mixed with "fluid" at the first mixing point as is the second concentrate at the second mixing point. The first and second mixing points are both to be located "intermediate said first and second ends of said first fluid conducting means". No other specific placement identification is given. The body of the specification is indifferent to order of mixing and teaches nothing of advantages of one order over the other. The well known prior art had machines that had both orders of mixing. 144 With respect, the views of Professors Coster and Schindhelm that there may be advantages in the order of mixing that they see described by the words "first" and "second" (which advantages are not found or described in the Patent) are not reflected in the prior art and were not compelling. 145 Of the respondent's arguments, the one with most force derives from the structure of the last paragraph of claim 2. Half-way through the paragraph, in an unbroken sentence, the part of the paragraph commencing "to thereby produce" was said to indicate that the mixing that has just taken place (the A solution) thereby produces the final product (the "prepared fluid"). It is necessary, it was submitted by the respondent, to force, or read in, a line break after "first fluid conducting means" and before "to thereby produce" to have the "thereby" qualified by all that went before – both mixings, rather than the immediately antecedent mixing. 146 I disagree. The meaning of the relative words ("to thereby produce") depends on the whole of the context in which they appear. It is a not uncommon drafting technique not to break a line in such circumstances. What is required, is an understanding as to what "to thereby produce" is referring to. In a context where the prior art, the body of the specification and the claims otherwise do not teach the reader any advantage by the order of mixing, I would not read "to thereby produce" as necessarily referring to what the immediately antecedent mixing did as the second mixing in time and space, that is, downstream of the first. The question is one of the construction of the words in their whole context: see generally Eastern Counties and the London and Blackwall Railway Companies v Marriage (1860) 9 HLC 32; 11 ER 639 at 44 and 644 per Channell B, at 46 and 645 per Bramwell B, and at 64, and 652 per Pollock LCB; and see A Selection of Broom's Legal Maxims (10th Ed 1939) pp 461-62. Claim 2 Conclusion 147 Thus, I agree with the applicants' submission that types 2 and 3 infringe claim 2. I take it to be common ground that claims 5, 24 and 25 are thereby infringed and that the elements dealt with above which appear in claims 11, 28 and 35, 80, 81 and 88 need no separate later consideration. Claim 4 "comprising" 148 No separate issue arises here. "outlet at the bottom thereof" 149 The first additional issue in relation to claim 4 is whether the respondent's biBag vessel containing powder concentrate includes (or has) an "outlet at the bottom thereof". 150 There is no hole or aperture in the biBag at the bottom. Rather, a tube inside the vessel, with a filter at its end at the bottom of the vessel draws fluid from the bottom of the vessel and takes it to the intermediate annulated ring at the top of the vessel. There are three rings. The middle ring has a hole which acts as the ingress of water. The intermediate ring has a hole to which the tube delivers fluid from the bottom of the vessel. The outer ring is used in affixing the biBag to the machine. This can be seen in exhibit TJW 17 which is the biBag emptied of powder. 151 The claim calls for "an outlet at the bottom of the vessel". 152 The vessel is used as part of a system for dialysis. Though it can be examined as a separate item, it is intended to form part of the dialysis system by affixation to the machine to form part of the hydraulic system. The filter covered end of the tube is the place from which the concentrate is conducted from the bottom of the vessel. To the extent that the whole of the tube from the filter to the mixing point (at the primary air separator or junction) can be seen as the third fluid conducting means, it can be accepted that the third fluid conducting means conducts concentrate solution from the bottom of the vessel to the mixing point. But does it communicate (with) outlet of the said vessel? Or, put another way, can it be said that there is an outlet of the vessel at the bottom of the vessel? 153 The applicants submitted that the claim provides a number of elements to understand the meaning of "outlet": (a) it is an outlet of the vessel; (b) it is at the bottom of the vessel; (c) it is the place from which the concentrate solution is conducted from the bottom of the vessel; and (d) the third fluid conducting means "communicating said outlet with a mixing point". 154 An outlet is defined in the Macquarie Dictionary as "an opening or passage by which anything is let out, a vent or exit". The New Shorter Oxford (1993) defines outlet as "an opening by which something escapes or is released; a means of issue or exit". 155 If one views the tube inside the biBag as part of the third fluid conducting means, which it is when affixed to the machine, the question is whether the concentrate fluid is to be seen as not yet let out or released or issuing from the biBag until it passes through the hole in the intermediate annulated ring at the top of the vessel. If the third fluid conducting means can be seen as including the tube that is in the biBag, the concentrate enters the third fluid conducting means at the bottom the vessel. When one looks at exhibit TJW17 (which is also LMB20) one is tempted to view the outlet of the vessel as at the top of the vessel at the aperture in the intermediate annulated ring, because that is where the hole is which delivers the concentrate from inside the vessel to outside the vessel through the intermediate ring. Nevertheless, in operation, and as part of the dialysis system, this hole and the passage through the intermediate ring is but part of the internal configuration of the third fluid conducting means which begins on the internal side of the filter at the end of the tube at the bottom of the vessel. 156 In this way, there is an outlet at the bottom of the vessel into the third fluid conducting means. The commencement of the passage by which the concentrate is let out of or exits the vessel is at the filter. The ingress or openings into the filter is or are how the concentrate escapes or is released fro m the vessel into the third fluid conducting means. 157 Professor Schindhelm saw the tube in the biBag as part of the third fluid conducting means. He saw no functional difference in part of the third fluid conducting means being inside the vessel from an aperture at the bottom of the vessel. He also agreed, as is clear, that by the use of the filter one can see the concentrate leaving the powder and passing on through the third fluid conducting means. He said the following: Catterns: Is it right to say that it exits the column of powder at the point of the filter. The concentrate solution exits the column of powder at the point of the filter? Schindhelm: In a practical way it doesn't. In a schematic way it does. Catterns: What do you mean by "In a practical way it doesn't"? Schindhelm: Practically it comes out the top in a schematic way, the orientation doesn't really matter. Catterns: In a functional way the orientation doesn't matter, I think you agreed? Schindhelm: Yes. 158 Examining the matter functionally, the fluid concentrate leaves the powder column and the vessel at the point it passes through the filter into the third fluid conducting means at the bottom of the vessel. In this sense, though the vessel is not cut or pierced at the bottom, nevertheless there is an outlet at the bottom. 159 The tube could exit the skin of the vessel from the bottom. No functional advantage is obtained by running it inside the bag up to the standard annulated fixture. The essence of the invention is as I have earlier described it. One essential integer is the use of powder in a vessel and dissolution of it by water on-line. In claim 4 the concentrate solution is conducted from the bottom of the vessel, where there is an outlet. Looking at the claim purposively (Populin v HB Nominees at 41-2) and recognising that the essential matter to which the words of claim 4 are directed is to conduct the concentrate solution from the bottom of the vessel into the third fluid conducting means out of the vessel and to the mixing point, it can be seen that how much tubing that constitutes part of the third fluid conducting means that is within the boundaries of the skin of the vessel is functionally immaterial, just as the precise location of the break in the skin of the vessel through which the fluid passes into the intermediate ring and continues along the third fluid conducting means is functionally immaterial. What is taught by the claims, read in the light of the specification, is that the outlet of the vessel is where the concentrate enters the third fluid conducting means (and thereby leaves, exits or is let out of the vessel) and as such is at the bottom of the vessel. That occurs in types 2 and 3. 160 The substantial idea disclosed by the body of the specification and made the subject of the claim 4 has been taken and embodied by the respondent in the biBag: Radiation Ltd v Galliers & Klaerr Pty Ltd at 51; Populin v H B Nominees at 41; and Bartlem Pty Ltd v Cox Industries (Aust) Pty Ltd [2002] FCAFC 224; 55 IPR 449,477-78 [59]. whether second fluid conducting means is "communicating with" the water source 161 No separate issue arises here whether the second fluid conducting means introduces water "into the top of the said vessel" 162 It was submitted that the biBag system does not introduce water into the top of the vessel (in the fashion which can be seen in figures 1, 2, 3, 4, and 7 in the specification). But these figures do not control the meaning of the phrase in the claims. One looks to the substance of what is disclosed and claimed. Looking at the claims in the light of what is taught in the specification, there is nothing which tells one that the top of the vessel is otherwise than at a point such that the water thus introduced on to the top of the column of powder such that it can be said that the water proceeds from the top of the column of powder to the bottom. The inlet of the biBag furnishes this result. I am fortified in this view by the evidence of Professor Schindhelm. 163 Understanding what is sought to be achieved in the biBag and what is sought to be expressed in the claim, against the background of the essence of the invention, it seems to me that the words of the claim are ample to encompass the inlet of water at the effective top of the vessel to enable water to pass from the top of the column to the bottom. mixing point "in" said first fluid conducting means 164 No separate issue arises here. whether the third fluid conducting means conducts concentrate solution from the bottom of the vessel. 165 This point is related to the question of whether there is an "outlet at the bottom of the vessel". The respondent submitted that there is no aperture at the bottom of the vessel (that is through the skin of the vessel), that the biBag system operates by use of pressure to force concentrate solution up the tube within the bag to an upper outlet, that the internal tube within the vessel is not part of the third fluid conducting means, that the fluid conducting means "communicates" with the upper outlet of the vessel at the annulated connection, that the word "conduct" (the claims use the word "conducting") means to serve as a channel or medium and that this is to be contrasted with the notion of "withdrawal" which was said to be a different action hydraulically. 166 Whilst the biBag system operates by pressure, so do all dialysis systems. Gravity also plays its part. All the conduits or fluid conducting means in the body of the specification and claims and in the types 2 and 3 and in the biBag operate passively. Thus, any use of the active voice ("conducts", "withdraws", "delivers", "communicates") should not mislead one into concluding that the conduit is anything other than passive. An aperture breaking the skin at the bottom of the vessel would see water withdrawn partly by the pressure of the system and partly by gravity; it might then move in any direction aided by the pressure within the system. The real question, the answer to which solves the debate here and the debate as to "outlet at the bottom of the vessel", is whether the tube with the filter is part of the third fluid conducting means. In use, as part of the system, that is, how the tube within the vessel acts. It can be seen to be an extension of the third fluid conducting means, but equally as part of the third fluid conducting means: see Professor Schindhelm at T pp 282 (11-16) and (27-28), and generally Tpp 282-83. 167 The tube inside the vessel is part of the third fluid conducting means. Once the biBag is fitted, there is one continuous conduit from the filter to the mixing point. That is how it is schematically represented. That was how Professor Schindhelm agreed it could be viewed. That is how I view it. Viewing the matter in this way, the tube passively conducts the concentrate solution from the bottom of the vessel, such that it can be said that the "third fluid conducting means communicating said outlet of said vessel … for conducting said concentrate solution from the bottom of said vessel." whether it is a "system … arranged such that a relatively constant concentration of dissolved powder concentrate is maintained in said third fluid conducting means by fluid being conducted through said vessel from its top to its bottom" 168 The respondent submitted that because of the presence of the tubing internally within the vessel a different process of dissolution takes place from that described in the Patent, being a flow of fluid from top to bottom. The respondent submitted that in the biBag the passage of fluid "experiences a pressure-driven reversal during operation and whereby diffusive and convective forces impact on the dissolution of the powder …" 169 Professor Coster's views on this topic were contained in his first and second affidavits. He described the factors that determine the dissolution of the solute and the production of concentrate solution as more complex in the biBag than the mere conducting of fluid "through said vessel from its top to its bottom." He described more complex processes as convective, diffusive and fluid-bed processes at work in the biBag. Paragraph 98 of his first affidavit and paragraphs 76 and 77 of his second affidavit encompass the point: [98] The bibag system operates by maintaining a constant pressure in the bibag so that as fluid (concentrate solution) is removed, additional water is added to the bibag. Water does not percolate from the top through to the bottom of the bicarbonate powder in the bibag; rather the bibag contains a decreasing quantity of the powder which sits in an approximately constant volume of water. This ensures that the solution in the bag is saturated. If concentrate solution is withdrawn slowly enough and replaced by an equal volume of water, the solution concentration remains relatively constant as the bicarbonate in solution diffuses through the volume. The process of mixing may also be aided by agitation and the swirling action of the solution as the concentrated solution is withdrawn via the tube and the cylindrical filter inserted into the lower portion of the bibag. … [76] In the bibag system employed in the Fresenius machines, the water is not simply passed through the column of powder concentrate; rather the bibag always contains a solution of bicarbonate together in which the remaining undissolved sodium bicarbonate is submerged. As additional water is added to the bibag, more of the bicarbonate is dissolved. Because the dissolution process occurs at a finite rate, a gradient in the concentration of the bicarbonate will be established in the solution in the bibag, from the least concentrated at the top of the bibag to a near saturated solution at the lower end of the bibag. This gradient in concentration will establish a diffusive flow of sodium bicarbonate from the lower end of the bibag to the solution at the top of the bibag. Such a concentration gradient also establishes an osmotic gradient which will lead to diffusion of water from regions of lower solute concentration to those of higher solute concentration. Water has a lower density than the bicarbonate solution and hence such an osmotic flow can also give rise to convection. The mixing which results from these diffusive and osmotic flows is in addition to the mixing resulting from the bulk flow of the solution from the top to the lower regions. All of these processes are also dependent on the size of the solute material (powder concentrate of the sodium bicarbonate), the shape of the vessel and temperature. The latter parameter is, as Mr West correctly points out, controlled in dialysis machines that were in actual use at the Priority Date. However, I note that Claim 11 does not specify the production of saturated solution but rather "a relatively constant concentration" of the solution. The concentration of a saturated solution, however, varies with temperature. Whilst in practice at the Priority Date dialysis machines were fitted with temperature control systems, the temperature control is not part of Claim 11 and the system described would therefore not necessarily produce "a relatively constant concentration" of the solution. [77] It is therefore not correct to state that the relatively constant concentration of dissolved powder is maintained by the "fluid being conducted through the said vessel from its top to its bottom" it is not simply the act of conducting the fluid through the vessel that achieves this end. 170 However, Professor Coster recognised that there is "bulk flow of the solution from the top [of the vessel] to the lower region [of the vessel]": see [76] above. 171 The "pressure driven reversal" is the fluid passing up and along the tube in the vessel, that is into and along (up) the third fluid conducting means. The existence of pressure does not distinguish the respondent's system. All such systems have pumps. Gravity plays a part in all systems also. 172 The applicants accepted that within the biBag there may be the processes described by Professor Coster, but submitted that even on that assumption infringement of the claim is not avoided. In terms of the claim, fluid enters at the top, passes through the solute and is conducted from the bottom of the vessel into the third fluid conducting means. It does not matter that the processes described by Professor Coster occur. The claims are not limited to a system employing only percolation and no other principle related to dissolution. 173 I accept the applicants' submissions in this regard. Whether or not some complexity of process is at work in the dissolution of solute in the biBag, the water is introduced at the top of the vessel and as a fluid moves to the bottom of the vessel. Even accepting Professor Coster's evidence it is correct to say of the biBag system that "a relatively constant concentration level of dissolved powder concentrate is maintained in said third fluid conducting means by fluid being conducted through said vessel from its top to its bottom". Claim 4 Conclusion 174 Thus, I agree with the applicants' submissions that claim 4 is infringed by each of the respondent's systems. Also claim 11, which adds to claim 2 the last discussed integer, also infringes. Claims 80 and 81 (that are dependent on claim 11) and in claim 28 (that is dependent on claims 2 and 4), are dealt with by the discussion above. Claims 28, 80 and 81 whether the biBag is a cartridge 175 The respondent's submissions emphasised two characteristics of a cartridge said to be absent from the biBag: the need for some rigidity of walls and for the form of the vessel to adapt so as to integrate with a holding device. 176 The specification identifies one type of vessel which may be utilised as a self-contained cartridge. There is reference to a "cartridge vessel" that is suitable for a single treatment. 177 I do not agree that the content of the phrase "self-contained cartridge" or the word "cartridge" is necessarily limited by the notions posited by the respondent. The Oxford English Dictionary (2nd Ed 1989) defines the word "cartridge" as: "1(a) the case in which the exact charge of powder for firearms is made up; of paper, parchment, paste board, flannel, serge, metal etc, according to use". The Chambers Dictionary of Science and Technology includes the following definition of "cartridge": "a cardboard tube for the carriage of a small quantity of chemical." In Random House Webster's Unabridged Dictionary (1999) a meaning of "cartridge" as "any small container for powder, liquid or gas, made for ready insertion into some device or mechanism: an ink cartridge for a pen. 178 I agree with the applicants' submissions that in the context of the particular application and of the invention it means something containing a pre-determined amount of powder concentrate to be placed into the hydraulic system for a single use and thereafter to be disposed and replaced. 179 I do not accept that either as a matter of ordinary meaning or within the context of the claimed inventions set in the specification, the vessel must have rigid walls to be a cartridge, or somehow fit integrally or snugly into some surrounding fixed framework surrounding the vessel. The biBag here does, in any event, fix to the machine by the outer annulated ring. I do not think that to be a cartridge it needs to be fixed at or by some other part of the vessel. Conclusions as to Claims 28, 80 and 81 180 Thus, these claims are infringed. Claim 88 whether the powder concentrate is arranged as a column between the inlet and the outlet of the cartridge 181 This is answered by the conclusion that the outlet of the biBag is at the filter at the bottom of the vessel, below the powder. whether the powder concentrated is arranged as a column … and is dissolved in water flowing through the vessel 182 The powder is arranged as a column. Professor Schinhelm was clear about this: Tp 292. It plainly is. 183 The discussion at [168] to [1746] above leads to the conclusion that the water flows through the vessel from the top to the bottom. whether the second fluid conducting means and the cartridge are so dimensioned as to produce a substantially saturated solution 184 The respondent submitted that the concentration of the solution produced by the biBag is not attributed to the dimensioning of the biBag and the tube which introduces water into the tube. 185 The biBag produces a saturated solution. The role that the second fluid conducting means and the design of the cartridge play in achieving saturation is described on page 8 of the specification as follows: …The concetrate [sic] line 8 and column 10 are suitably dimensioned in such a manner that as the water drawn into the concentrate fluid circuit 8 is conducted downwardly through the column 10, a substantially saturated solution of the powder concentrate in water is obtained, to thus produce a concentrate fluid which is then conducted from the column 10 and introduced into the main line 1 at mixing point 7. … 186 Professor Schindhelm explained in cross-examination that if one is attempting to dissolve a salt in water and get a given concentration (here, a saturated solution at a given temperature) it is a function of flow rate and the shape of the container and hence the contact or residence time of the water with the powder solute. The flow rate affects residence time of the water with the powder or solute. The flow rate can be altered by the pump, or by altering the size of the conduit. The shape of the container is also relevant to dissolution. Accordingly, in my view, the biBag and the second fluid conducting means are so arranged and dimensioned as to produce a saturated solution. Conclusions on Infringement 187 Thus, I accept the contentions of the applicants that the respondent's systems and articles infringe the Patent. Novelty general principles 188 The anticipation which was debated between the parties was limited to three paper anticipations to which I will refer as the Stasz Patent, the Mund Patent and the Alza Patent or sometimes as Stasz, Mund or Alza. No issue arose as to the change to the notion of prior art in the definition of "prior art base" in Schedule 1 of the 1990 Act. 189 Both parties filed submissions on the applicable legal principles. I do not, however, understand the parties to be at issue on any question of legal principle which I take to be as follows. 190 The prior disclosure must reveal the totality of the invention: Hill v Evans (1862) 31 LJ Ch 457, 463; 4De G F & J 288; 45 ER 1195 (per Lord Westbury); Olin Corporation v Super Cartridge Co Pty Ltd (1977) 180 CLR 236, 261; N Guthridge Ltd v Wilfey Ore Concentrator Syndicate Ltd (1906) 3 CLR 583, 589, 599; and Van der Lely NV v Bamfords Ltd [1963] RPC 61, 71-2. 191 The basic test for want of novelty is reverse infringement: Meyers Taylor Pty Ltd v Vicarr Industries Ltd (1977) 137 CLR 228, 235; and RD Werner & Co Inc v Bailey Aluminium Products Pty Ltd (1989) 25 FCR 565, 568-69. However, as Gummow J (Jenkinson J agreeing) said in Nicaro Holdings v Martin Engineering (1990) 91 ALR 513, 528, the test described by Aickin J in Meyers Taylor is only "generally" applicable. Gummow J said: …Where the alleged anticipation is a paper publication, particularly a prior patent specification, there may be ground for debate in a comparison with the specification in suit as to the presence of inessential integers and mechanical equivalents. King J pointed this out in his judgment at first instance in Werner's case, supra (IPR at 536; ALR at 702). There may also be dispute whether what has been disclosed sufficiently reveals an essential integer, in the light of the principles in Hill v Evans (1862) 4 De GF & J 288: see Werner's case (ALR at 683) per Lockhart J. 192 Whilst it is not entirely helpful to speak in terms of metaphors of signposts and flags (see General Tire & Rubber Co v Firestone Tyre & Rubber Co Ltd [1972] RPC 457, 485-86), it is necessary to recognise that the prior publication must contain clear and unmistakable directions to do what the patentee claims to have invented: General Tire & Rubber Co v Firestone Tyre & Rubber Co Ltd at 485-86; ICI Chemicals v Lubrizol Corporation (2000) 49 IPR 513, 527 at [49]; and Bristol-Myers Squibb Company v FH Faulding & Co Ltd (2000) 46 IPR 553, 576 at [67]. The Stasz Patent 193 The first anticipation asserted was US patent no. 4,386,634 for a proportioning system in the names of Peter Stasz and Louis C Cosentino. 194 The relevant filing date was 10 October 1980. The abstract to the patent describes it as a proportioning system "for preparing hemodialysis or hemofiltration solutions". The abstract states: A proportioning system for preparing hemodialysis or hemofiltration solutions. The apparatus of the system is a specially plumbed tank containing a flexible plastic container which holds solution concentrate. Introduction of pressurized water in to the tank outside the bag discharges concentrate and water through separate paths into a mixing chamber at a rate determined by the size ratio of narrow orifices in the respective paths. 195 It is convenient to describe the Stasz Patent by reference to the diagram in the patent, which is as follows: 196 Stasz provides for a system of preparing a dialysis or replacement fluid or component fluid thereof. What is described, however, is a two-staged process controlled by valves. The tank (18) holds a collapsible flexible container such as a plastic bag in which a pre-determined amount of solute is contained. The first stage involves the conveying of water from 12 along 10, through a pressure regulator 14 to the tee 16; during this stage valve 34 is blocked preventing water passing through it along 20 into the tank; rather, the water proceeds along 36 to a three-way valve at 40 which is in a position to block the water along paths other than toward the tank and bag, via valve opening 44; after passing through valve opening 44, the water passes into the interior of the bag 48 through conduit 50 to dissolve the solute in the bag. As the bag expands with water added, air is expelled through vent 74. When the bag is filled, vent 74 is closed, valve 40 is placed into a position permitting flow between 44 and 46, but not through 42, so fluid concentrate can be forced out of the (now filled) bag and thereafter proceed along conduit 62. 197 The second stage involves the opening of valve at 34 to permit water to pass from 12, along conduit 10, past tee 16, through valve 34 and along conduit 20 into the tank containing the filled bag. As the tank fills with water under pressure from regulator 14, water will either exit the tank by conduit 66 or displace solution in the bag driving the solution up through conduit 62 into the mixing chamber 64 with the water that has left the tank through conduit 66. The flow rates of the water and solution into the mixing chamber 64 will be determined by the size of the orifices at 60 and 70 with the water under identified pressure from pressure regulator 14. 198 The respondent submitted based on Professor Schindhelm's evidence that the first, second and third fluid conducting means were as described pictorially below: first fluid conducting means second fluid conducting means third fluid conducting means 199 Each side provided a schedule or matrix to deal with each of the integers in the claims in the Patent. I will come to the particulars of the asserted anticipation (by the respondent) and the asserted differences (by the applicants) in due course. The fundamentals of the differences between the parties are as follows. 200 The applicants stressed that there is never a moment when, under Stasz, there is preparation of dialysis or replacement fluid by mixing concentrate powder with water in a dynamic way. In Stasz, the solute is dissolved in the bag, the valves are changed and the water flows into the tank forcing out concentrate and water in ratios determined by the two orifices. What the applicants say is disclosed and taught by Stasz is a proportioning system mixing water with liquid concentrate pre-prepared. The second fluid conducting means does not operate at the same time as the first and third. 201 The applicants submitted that at no point is there a moment where the integers identified in the Patent – the first, second and third fluid conducting means are present – at the same time. For the same reason the vessel (the bag) does not have an inlet or an outlet at the same time. The hole at the top of the bag is an inlet in stage 1 and an outlet in stage 2. The outlet when present (in stage 2) is at the top of the vessel. 202 Further, the applicants submitted that the relevant integers going to the addition of a second concentrate circuit are absent and that none of the integers relating to the conducting of fluid from the top to the bottom of the vessel through the powder concentrate was present. 203 These broad differences between Stasz and the Patent as submitted by the applicants were challenged by the respondent, by reference to what the Patent and specification did, and did not, teach. Fundamental to the respondent's submission is that the Patent is not limited to in-line continuous production; but that it caters for and includes systems of production that are not of that character. It was submitted both that there was nothing articulated in the Patent so to confine it and that there were positive indicators within the specification that the ambit of the claims is not so confined. 204 The asserted positive indication in the specification relied on by the respondent was on page 5c of the specification in the passage to which I referred, and which I discussed, above. I do not repeat what I there said. Initially page 22 (lines 18-20) was also relied on in support of this proposition. This was the passage dealing with storage referred to at [96] above. In final address, it was conceded that the reference to storage was there to the A concentrate and not the B concentrate produced by the operation of the system described in the Patent. This discussion of storage of the A concentrate can be seen to contrast with the lack of any discussion of problems with storage of B concentrate, in the context of a discussion of cartridges for the production of such concentrate. 205 The respondent submitted that the Patent does not require continuous preparation. The concentrate produced from the dissolution of the powder could be directed into a holding tank or container. I reject this submission. Whilst the Patent does not provide for any particular configuration of the third fluid conducting means, it would be clearly not one fluid conducting means if the concentrate was stored for later use and later withdrawn for mixing in the first fluid conducting means. The respondent sought to support the notion of a holding tank being part of the third fluid conducting means by pointing to Professor Schindhelm's view that the tank in operation in Stasz was part of the first fluid conducting means. However, that view of Professor Schindhelm does not support the respondent's assertion. In Stasz the tank can be seen as contemporaneously part of the conduit; it is not a storage vessel for the later withdrawal of fluid. 206 Professor Schindhelm also referred to the passage on page 5c of the specification. However, as I have said earlier, in the context of the prior art it is tolerably clear, in my view, that what the Patent discloses is the continuous on-line production of concentrate and its mixing with water contemporaneously, or on-line. That conclusion is sufficient to lead to the conclusion that Stasz does not anticipate the Patent. 207 I turn now to the integers of the various claims in the Patent. I will deal with each claim and limit my comments to integers not disclosed in the Stasz Patent. Claim 1 208 In Stasz there is no first fluid conducting means having, other than temporarily, a first end communicating with the source of water, nor is there at all times in the operation of the system a first fluid conducting means. 209 In Stasz there is no second fluid conducting means communicating, other than temporarily, with the source of water and with the inlet of the vessel. Valve 40 closes in the second stage. Nor is there at all times in the operation of the system a second fluid conducting means. 210 In Stasz there is no third fluid conducting means communicating, other than temporarily, with the outlet of the vessel; nor is there at all times in the operation of the system a third fluid conducting means. 211 These conclusions rest on the two stage approach of Stasz. To the extent that I am wrong in that regard I do not think that the Stasz Patent contains clear and unmistakable directions to do what is claimed in claim 1. 212 The applicants also said that the Stasz Patent did not include the following integers of claim 1: (a) a flow regulating means (b) located in said third fluid conducting means (c) and being responsible to said measuring means (d) for controlling the flow of said concentrate solution from said vessel. 213 Professor Schindhelm identified that the Stasz Patent (at col. 4 l 54) referred to a conductivity meter. There the Stasz Patent stated: A conductivity meter, not shown may be interposed in the flow path downstream from missing chamber 64 and provide assurance of the precision and accuracy of the dilution. 214 This is plainly a fail safe device since it is after the mixing chamber 64. Professor Schindhelm agreed that the Stasz Patent did not expressly disclose flow regulating means responsible to the conductivity meter. He also agreed that the flows in Stasz was primarily controlled by the orifices. (See generally Tpp 287-89.) 215 The evidence supports the applicants' submissions in this regard. 216 Claim 1 is not anticipated by the Stasz Patent. Claim 2 217 The above deals with the same or substantially the same aspects of claim 2. 218 Claim 2 has a fourth fluid conducting means communicating with a second source of concentrate. Professor Schindhelm at [49] and [50] of his first affidavit described how the Stasz Patent describes the use of a second concentrate: 49. The system described in the Stasz Patent clearly describes the use of a second concentrate. At column 4 lines 49 to 53 the Stasz Patent describes: "The exit flow from the mixing chamber 64 is connected by fitting 88 to the dialyser solution feedline or to another pre-portioning system in which the solution may be further diluted or mixed with additional dialysing solution ingredients". Again at column 4 lines 59 to 68: "By another variation, only some of the requisite reagents would be contained in the plastic bag… This concentrate could then be combined with a concentrate of the remaining reagents from another source, such as a second unit of this invention to produce the dialysis solution". 50. It is clear to me … at the Priority Date, that the second concentrate, referred to, would be added to the system before "fitting 88". It is clear that the solution passing from "fitting 88" flows to the dialyser. The second concentrate would have to be added to the solution before it enters the feedline of the dialyser because the dialysis fluid that flows into the dialyser (see paragraphs 29 to 32 above) must comprise the final solution (ie the A and B concentrates plus water). 219 Professor Schindhelm agreed that the Stasz Patent does not describe a second proportioning system being plumbed in with a mixing point upstream of 88. Professor Schinhelm used his skill or knowledge. 220 I conclude that there is a disclosure to someone skilled in the art of another possible source of concentrate solution before 88. Again, however, whether that source was another Stasz device or not it could only operate temporarily. If it were another Stasz device as Professor Schindhelm describes in [54] of his second affidavit and exhibit KS-18 to that affidavit there is no clear disclosure of how to combine the two Stasz units in the Stasz Patent. 221 This connection to another Stasz device also leads me to conclude that there is no second end of the first fluid conducting means for delivering a prepared fluid for use in haemodialysis, haemofiltration or haemodiafiltration, rather the exit flow is converted by fitting 88 to another proportioning system. 222 Thus claim 2 is not anticipated. Claim 4 223 I do not repeat the issues common to claim 4 dealt with the above. 224 There is no outlet at the bottom. The reasons why the respondent's biBag does infringe are irrelevant to this conclusion on Stasz. 225 Further, the third fluid conducting means (see [200] above) does not conduct said concentrate solution from the bottom of the vessel. The concentrate is forced out of the top of the vessel into the third fluid conducting means. 226 Nor is a relatively constant concentration level of dissolved powder concentrate maintained in said fluid conducting means by fluid being conducted through said vessel from its top to its bottom. It is mixed in the vessel (stage 1) and then forced out the top (stage 2). 227 Claim 4 is not anticipated. Claim 5 228 To the extent that it is dependent on claims 1, 2, 3 or 4, it is not anticipated. 229 Also, the Stasz Patent does not identify a reservoir for containing water. 230 Claim 5 is not anticipated. Claim 6 231 This claim is dependent on claims 1 and 5 and is so not anticipated. Claim 11 232 This claim is dependent on claim 1 or claim 2 and so is not anticipated. 233 Further, the outlet of the vessel in Stasz is not at the bottom, and water is not conducted through said vessel from the top to the bottom. Claim 24 234 The respondent's submissions did not deal with some claims, including claim 24; the applicants filed submissions. I will deal with the matters dealt with by the applicants. 235 This claim is dependent on claim 1 or claim 2 or claim 4 and so is not anticipated. 236 Further, the Stasz Patent does not identify powder concentrate of a particular micron size. Claim 25 237 Like claim 24, the applicants did, but the respondent did not, file submissions on this claim. 238 This claim is dependent on claim 24 and is thus not anticipated. 239 Further, the Stasz Patent does not identify powder of a particular micron size. Claim 28 240 This claim is dependent on claim 1 or claim 2 or claim 4 and so is not anticipated. Claim 35 241 This claim is dependent on claim 28 and so is not anticipated. 242 Further, Stasz does not identify the quantity of bicarbonate material as being in the order of 400 to 900 grams. It was submitted by the respondent that at the time of the publication of the Stasz Patent it was known that a typical dialysis treatment involved the use of approximately the amount of bicarbonate specified in the claim. Nevertheless, the Stasz patent does not unmistakably teach this matter. Claim 77 243 Like claims 24 and 25, the applicants did, but the respondent did not, file submissions on this claim. 244 The applicants raised various matters in relation to claim 77 primarily based on the temporary nature of the fluid conducting means, which I have earlier referred to. The applicant also put submissions as to flow regulating means and measuring means. I have dealt with these matters earlier. Claim 78 245 Again, the respondent did not put any submissions on this claim in their schedule. Nevertheless, the applicants dealt with this claim and referred to the temporary nature of the fluid conducting means and the fact that the communication with the source of water which I take to be a submission based on the two stage nature of the Stasz Patent. I have already indicated that I accept these submissions. Claim 79 246 Once again the respondent did not put submissions in relation to this. The applicants, however, relied on the fact that the Stasz Patent did not identify a reservoir. I do not repeat what I have earlier said about this. Claim 80 247 There is no anticipation based on the absence of all features of preceding claims. Claim 88 248 This is dependent on claims 28 to 30 which are not anticipated. 249 Further, the powder concentrate is not arranged as a column; it is not arranged as a column between the inlet and outlet of the cartridge; the powder concentrate does not become dissolved in water flowing through the vessel; and the dissolution takes place otherwise than by reason of the second fluid conducting means and cartridge being so dimensioned as to produce a substantially saturated solution of the powder concentrate in water. 250 The Stasz Patent does not anticipate. The Mund Patent 251 The second anticipation asserted was a German Patent Application No DE 3443911A1 in the names of Andreas Alexander Mund and Dieter Glatzel with a filing date of 1 December 1984. 252 The Mund Patent is described as: A method of preparing a dialysate solution, and a mixing and storage tank used therefor. 253 The following figure from the Mund Patent aids comprehension: 254 The method of preparation is by use of a tank with "blank" water or water produced by reverse osmosis. 255 The problem sought to be solved was described as follow: The concentrated salt solution has hitherto been supplied to the dialysis centres as a ready-made mixture in upright tanks or filled in 10 litre canisters. This necessitates a large storage capacity if the cost advantages of supplies of large amounts of liquid are to be realized. 256 The Mund patent then describes the solution to the problem as follows: The method according to the invention for preparing the dialysate solution is accordingly characterized in that a first part of the "blank" water prepared from tap water is routed into the dialysis device and a second part is routed into a tank vessel. After introducing a settable amount of salt and additives into the tank vessel, the solution in the tank vessel is thoroughly mixed so that a desired amount of this solution can then be routed into the dialysis device. The "blank" water is in this case introduced into the tank vessel when only a predetermined small amount of solution is still present in the tank. In addition, a defined amount of "blank" water is added each time to the tank. 257 The Mund Patent describes the method for preparing the dialysate solution as taking "blank" water prepared from tap water and routing it into the dialysis device and a second part of the "blank" water is routed (via flow line 12) into the tank (10). After introducing a settable amount of salt and additives through the closable opening (50), the solution in the tank is thoroughly mixed by a stirrer (26) which can be adjusted up and down (as shown by the broken lines). When the solute is dissolved, the solution can be routed into the dialysis device via the outflow line (14). There are sensors at the top and the bottom (32 and 30) connected to measurement and central devices (40) via lines (36 and 34). A minimum level of liquid is kept in the tank at level 60 and a maximum at level 62. The sensors (30 and 32) not only control the levels but they also measure the concentration of the solution by its conductivity. The inflow of blank water into the tank remains interrupted as long as the level is between the minimum and maximum. The stirrer remains turned on as long as the conductivity of the solution does not meet the desired measurement. Once the stirrer ceases, the solenoid valve (22) is released so that the concentrate solution can be delivered via the pump (20) to the dialysis device via the outflow line (14). Once the level reaches 60 the pump (20) and solenoid valve (22) are closed and the solenoid valve (15) is released so that blank water is introduced up to level 62, so that a new cycle for preparing and storing concentrated salt solution begins. 258 I will deal with the particular integers of the claims of the Patent in due course. At a general level, however, I accept the applicants' submissions that the Mund Patent does not anticipate because it does not teach, as the Patent does, a continuous on-line production of concentrate. The given volume of acceptable concentrate is produced in cycles. It must flow out to a storage tank, then as pre-prepared concentrate to be mixed with blank water by a proportioning machine. The outflow is not apparently regulated by the desired mixture with blank water to produce dialysis solution of an acceptable mixture; rather, the tank is drained at the conclusion of the cycle so that the second mixing cycle can begin. 259 It is a system for mixing a cycle or batch of concentrate for use in a dialysis device. It does not involve a vessel containing powder concentrate; it does not involve a second fluid conducting means communicating with a source of water and an inlet of the vessel and a third fluid conducting means communicating with the outlet, at the same time; it does not involve any mixing points; it does not involve any integer relating to the conducting of fluid through a powder concentrate; it does not involve a cartridge. Claim 1 260 The powder concentrate is added to water in a tank, it is not "a vessel containing a powder concentrate". The Patent teaches and the claim encompasses a vessel with powder, into which the water from the second fluid conducting means flows. The Mund Patent teaches a mechanical equivalent in this respect of the nurse stirring the tank. 261 There is no communication of the second fluid conducting means with both the source of water and the inlet of the vessel during preparation. 262 A concentrate solution is not "thereby" produced by introducing water into the vessel, but by adding powder and mechanically mixing after a tank with a small amount of solution has been filled. 263 The third fluid conducting only communicates with the outlet of the vessel after the preparation cycle is complete. 264 There is not communication of the third fluid conducting means with a mixing point in any first fluid conducting means, whether intermediate of the first and second ends of the first fluid conducting means, or otherwise. 265 The measuring means which exist are located not in the first fluid conducting means but in the vessel (10); and are upstream of any mixing point (even though a mixing point is not identified). 266 The flow regulating means do not regulate the flow of the concentrate into the mixing point, but close or open the valve to release fluid from the tank or prevent fluid leaving the tank. Claim 2 267 I do not repeat the matters referred to in respect of claim 1 above, which are also applicable to claim 2. 268 There is no clear disclosure of a second source of concentrate. The Mund Patent does disclose a "dialysis device". It was said that such a device would necessarily contain an acid solution. However, the claims of the Patent are not anticipated clearly by a patent dealing with one method of mixing and preparing the bicarbonate concentrate solution. 269 There is no fourth fluid conducting means having a first end communicating with said source of second concentrate and having any or all of the integers in the last paragraph of claim 2. Claim 4 270 I do not repeat any matters referred to in respect of claims 1 and 2 which are also relevant to claim 4. 271 Whilst the vessel has an inlet at the top and an outlet at the bottom, only one of the inlet or outlet is open at any one time, and neither works as an inlet or outlet during mixing. There is no clear and unmistakable teaching of the use of an inlet and an outlet at the same time for the introduction of water into a vessel already containing powder, which is what is involved in the Patent. 272 Whilst the Mund Patent produces, after the preparation cycle, a relatively constant concentration level of dissolved powder for passage into the third fluid conducting means, this does not occur by the fluid being conducted through the vessel from top to bottom but by being stirred and, when prepared, let out of the vessel. Claim 5 273 To the extent it depends on claims 1 or 2 or 3 it is not anticipated. 274 The Mund Patent calls for "blank" water but not a reservoir. Claim 6 275 To the extent that it is dependent on claim 5 when appended to claim 1 it is not anticipated. Claim 11 276 To the extent that the claim is dependent on claims 1 or 2 it is not anticipated. 277 Whilst "blank" water is introduced into the tank, it is not conducted through the vessel from the top to the bottom. It is introduced into a closed tank, powder added, stirred and then let out at the bottom. Further, the relatively constant concentrate level of concentrate is not maintained in the third fluid conducting means by ("whereby") water being conducted through the vessel from top to bottom. Claim 24 278 The respondent did not assert in its schedule that claim 24 was anticipated. The applicants addressed the claim. To the extent that it is dependent on claims 1,2 or 4 it is not anticipated. 279 Further, the Mund Patent has no identification of powder of any micron size. Claim 25 280 The respondent did not assert in its schedule that claim 25 was anticipated. The applicants addressed the claim. To the extent that it is dependent on claim 24 it is not anticipated. 281 Further, the Mund Patent has no identification of powder of any micron size. Claim 28 282 To the extent that the claim is dependent on claims 1, 2 or 4 it is not anticipated. 283 The tank or vessel is not a self-contained cartridge containing a quantity of powder concentrate suitable for one treatment procedure. It is a tank which is filled with water and then a desired amount of powder is placed into it. 284 The tank does not answer the description of a cartridge in the way the biBag does. It is not affixed to the machine for use as a self contained unit. It is a vessel in which a process takes place after water and salts are placed into it. It does not contain a quantity of said powder it is a vessel into which that is placed after the water. Claim 35 285 To the extent that the claim is dependent on claim 28 it is not anticipated. 286 Whilst the quantity of bicarbonate material for dialysis treatment was well known, the Mund Patent does not expressly identify the quantity of bicarbonate material in the cartridge as does claim 35. Claim 77 287 The respondent did not assert in its schedule that claim 77 was anticipated. The applicants addressed the claim. 288 I do not repeat comments on integers common to earlier claims and for reasons earlier given the integers of the claim are not anticipated. Claim 78 289 The respondent did not assert in its schedule that claim 78 was anticipated. The applicants addressed the claim. To the extent that it is dependent on claim 77 it is not anticipated. Claim 79 290 The respondent did not assert in its schedule that claim 79 was anticipated. The applicants addressed the claim. To the extent that it is dependent on claim 78 it is not anticipated. 291 Further, whilst the Mund Patent calls for "blank water" it does not call for a reservoir. Claim 80 292 All features of no proceeding claim are present. 293 The tank is not a cartridge. 294 The tank is not a cartridge containing a quantity of powder suitable for one treatment. Claim 88 295 To the extent that the claim is dependent on claim 28 (within claim 28 to 30) it is not anticipated. 296 The introduction of a settable amount of salt and additives into the tank vessel is not the powder concentrate arranged as a column in the vessel. 297 There is no powder concentrate arranged as a column between the inlet and outlet of the cartridge. There is powder poured into the tank to be mixed with water added. 298 The powder concentrate does not become dissolved in water flowing through the vessel. The powder concentrate is dissolved in water by the process of dissolution assisted by a mechanical stirrer. The second fluid conducting means, the inflow line and the tank are not so dimensioned as to produce the substantially saturated solution of powder concentrate and water. That is produced by the mechanical stirring of the water and powder in the tank. 299 The Mund Patent does not anticipate the Patent. The Alza Patent 300 The Alza Patent relates to a parenteral delivery system. It is US Patent No 4,479,794 in the names of Felix Theeuwes and John Urquhart with filing date 11 October 1983. 301 The abstract discloses the following: A parenteral delivery system is disclosed for administering a beneficial agent to a recipient. The system comprises (a) a container of a medical fluid; (b) a primary tubing in communication with the container; (c) a parallel tubing connected to the primary tubing having a formulation chamber connected thereto, the formulation chamber housing a beneficial agent, or a device for delivering a beneficial agent; and (d) a common tubing connected to the primary tubing and the parallel tubing for administering the fluid and the agent to a recipient. 302 The Alza Patent is most easily understood by reference to figures 1 and 2 in the Alza Patent: 303 The disclosure of the invention refers to a primary fluid path and a parallel fluid path comprising a formulation chamber for admitting a beneficial agent into the primary path. (See column 2 ll 42-48.) 304 Another object of the invention is stated to be to provide a parenteral delivery system comprising a primary fluid path and a parallel fluid path comprising an agent formulation chamber housing a beneficial agent that forms in situ with fluid than enters the chamber from the primary path, an agent solution that is conveyed back to the primary path for administration to an animal, including a human patient. (See column 2 ll 56-64.) 305 Other objects of the invention are stated to be as follows: Another object of this invention is to provide a parenteral delivery system that comprises a means for automatically constituting an agent formulation in situ by dissolving a given amount of agent in a given volume of fluid that can be administered at any selected time. Another object of this invention is to provide a parenteral delivery system that makes attainable a program of agent administration adapted to a specific need by furnishing an agent formulation comprising a known volume of fluid containing from a trace to a saturating amount of a beneficial agent that can be administered at any chosen time. 306 The forms of agent said to be able to be used in the chamber 21 include solid, crystalline, microcrystalline, particle and powder forms. Under the heading "Modes for Carrying Out the Inventions" the following appears (column 5 ll 40-64 and column 6 ll 12-18) Agent formulation chamber 21 generally will store an amount of agent for executing a prescribed therapeutic or beneficial program. That is, an amount of agent for the pre-programmed, delivery of a therapeutically or a beneficially effective amount of the agent to produce a therapeutic or a beneficial result. Agent formulation chamber 21 generally will have a capacity of from about 10 milliliters to 250 milliliters of fluid or more, and it can house from about 5 milligrams to 20 grams of agent or more. The expression beneficial agent, as used herein, generically denotes any substance that produces a therapeutic or a beneficial result, such as a drug, a carbohydrate, an electrolyte and/or the like. The term fluid or liquid denotes a fluid, or a liquid that can be administered parenterally including intravenously, comprising pharmaceutically acceptable fluids that are also a pharmaceutically acceptable carrier for an agent, such as water, isotonic saline, Ringer's lactate, and the like. The term formulation, and agent formulation as presently used therein, generically indicates the beneficial agent is formulated, mixed, added dissolved, suspended, solubilized, formulated into a solution, carried and/or the like in or by the fluid in a physical-chemical form acceptable for parenteral including intravenous administration. … [emphasis added] … The amount of agent in a formulation made in chamber 21 can be a trace amount to a saturating amount. The delivery devices, in one presently preferred embodiment are devices that cease releasing agent or shut themselves off in the presence of a saturated agent formulation, that is a saturated solution. 307 The Alza Patent calls for flow regulation by adjustment of valves (18) and (27), which are hand controlled and are not controlled by any measuring device. 308 The system disclosed by the Alza Patent being, for parenteral delivery, does not disclose a system for preparation of haemodialysis fluid. Any anticipation relates to replacement fluid and haemofiltration. 309 The critical issue in relation to Alza in regard to haemofiltration or the anticipation by Alza Patent of the Patent in respect of replacement fluid is whether Alza unmistakably teaches that you could put water in 11 and B concentrate powder in the vessel 21 and use the hand controlled valves to regulate the flow into the cartridge (27) or within the primary fluid line (18). 310 Professor Schindhelm gave the following evidence in cross-examination about the Alza Patent: Catterns: Now, what would you say about the desirability of using this to make and deliver to a patient's vein a saline solution using pure water in 11 and sodium chloride salt in 21? Schindhelm Pure water in 11? Catterns: Yes? Schindhelm: Pure [saline] in 11? Catterns: Yes? Schindhelm Going through to 17 in the patient? Catterns: Yes. Schindhelm: I would be extremely cautious of it. I would like to see a hell of a lot of validation data on it to see what it actually does. Catterns: And why would you be cautious? Schindhelm: Because basically there is no detection means ensuring what is going into the patient. To overcome that you need a fair amount of validation to confirm that. Catterns: Are you concerned that we might end up with haemolysis? Schindhelm: Or worse, yes. Catterns: Because the balance - you would not trust two clamps of that type to be the sole mains regulating the balance of water and sodium chloride? Schindhelm: The way I would read this would be that even though you could use 18 and 27 as flow regulating means to adjust flow, if I was using this I would probably have all or nothing. I couldn't see that you would have 27 open and 18 open at the same time unless there's something on here that I'm not seeing. Catterns: What about twiddling a knob so that a bit goes through each? Schindhelm: That's possible but I wouldn't like it stuck in me. 311 The respondent stressed the reference to water in the passage from column 5 ll 40-64 referred to at [306] above. Notwithstanding Professor Coster's evidence, I would not read that reference as any teaching by the Alza Patent that water could be used as the fluid in the container 11 to be passed along the primary path and parallel path, in the latter to dissolve an agent. Professor Schindhelm's evidence and much of Professor Coster's evidence makes that plain. Professor Coster in his cross-examination stuck somewhat doggedly to the words in this part of Alza. He refused to accept that the reference to water was what could be included in the parenteral fluid. Whether or not the construction of the word and this part of the Alza Patent leave open the possibility of container 11 having water, I do not think someone understanding the dangers of haemolysis and armed with Professor Schindhelm's knowledge would conclude that Alza unmistakably disclosed what the patentee of the Patent sought to claim in relation to the preparation of fluid for haemodialysis and related procedures. My preferred construction of this part of the Alza Patent is that the fluid is one which can (without the addition of the agent in the chamber) be administered parenterally. The word "water" is thus used inclusively as part of such fluid. 312 The cross-examination of Professor Coster in this area and his somewhat argumentative approach led me to think at times that he was tending to advocate a position. To some extent I would view his evidence in this regard in that way. 313 However, when asked about the flow control mechanisms (18 and 27) Professor Coster gave evidence not dissimilar to Professor Schindhelm: Howard: If we just assume that there is water in that glass container rather than fluid? Coster: Yes. Howard: There is a possibility isn't there Professor that the water could be administered intravenously to the patient, there is not a sufficient means for stopping the flow? Coster: Well you would have to very carefully adjust 18 and 27 to get the right mix. … Howard: So the only way that you can regulate the flow through these paths, according to this patent is by use of that particular device isn't it that is marked at 27 and 18? Coster: Well I think it's a symbolic thing. It says a way of controlling the flow. Now if you wanted to control it accurately, you would have to have a proper, preferably electronically controlled flow system. You wouldn't do it by hand. I think the drawing indicates a flow control system and this would be one of them that would be crude, this would be crude, I wouldn't want to put that into a patient without having a much better flow control system. … Allsop J: Would you understand therefore, in figure 1, Professor, that the type of control system identified there by those clamps whether they're wheel clamps or some cognate method is to open and close the flow? Coster: It is to control the flow. To be able to have a flow rate through 19 at a given rate and a flow rate through 16 at a different rate, I mean down the bottom 16 below 18. Allsop J: Using that type of mechanism in a fairly rough way? Coster: Well that's very rough there, if you did it this way it would be very rough. You would not stick that into a patient unless you had better control. Howard: So you would have to use something very safe in the container like saline, you couldn't risk water being - - - ? Coster: But that may not be your option, you may not have that luxury. I would replace 27 and 18 by a proper control system. Howard: What it describes at columns 5 to 6 Professor, is a valve or a clamp, it is not - - -? Coster: Yes. Howard: The sorts of persons who'd be operating the valves or clamps would be whoever is in the hospital, a physician, a nurse or a practitioner? Coster: Yes. Howard: To put it bluntly Professor, no one in their right mind would want the responsibility of producing a stream of fluid of relatively constant concentration by manually adjusting these clamps or valves would they? Coster: No. Howard: Because otherwise, you'd end up with what we discussed yesterday, you'd either have haemolysis or you'd have crenation, you'd have a very sick patient? Coster: Exactly right. 314 Thus, I agree with the general submissions of the applicants that the Alza Patent does not clearly teach the present invention. In substance because it does not anticipate or otherwise unmistakably indicate the use of water as the fluid passing along the primary and parallel paths from the container. 315 Further, in column 6 the reader is taught that in one preferred embodiment the device ceases releasing the agent in the presence of a saturated agent formulation. This tends, as Professor Coster appeared to agree, to teach that it is undesirable to reach saturation, since at this point the device will cease releasing agent or shut itself off. 316 Turning to the detailed submissions of the parties on the integers to the various claims, it is unnecessary to identify those which have as their essential content the use of water. Claim 1 317 The Alza Patent does not have measuring means or measuring means located in the first fluid conducting means (the primary path) downstream of the mixing point (26). 318 The Alza Patent does not have a flow regulating means located in the third fluid conducting means (19) below the container (21) – the manual control mechanism (19) is above the container (21) in the parallel path. 319 The Alza Patent does not have flow regulating means responsive to measuring means. Claim 2 320 I do not repeat the matters referred to above. 321 The respondent does not claim anticipation by the Alza Patent other than for claims 4 and 88. The applicants provided submissions in relation to all the claims and integers to which I have otherwise referred in relation to the Stasz and Mund Patents. 322 Dealing with claim 2 insofar as the applicants have dealt with the matter, I do not repeat the comments I made above, in particular about water. There is no second source of concentrate solution identified in the Alza Patent. 323 There is no fourth fluid conducting means there identified. Therefore, the last paragraph of claim 2 is entirely absent. Claim 4 324 I do not repeat what I have earlier said in particular about water. 325 On the disclosure of the Alza Patent and as discussed in evidence with both Professor Schindhelm and Professor Coster the Alza Patent does not disclose a system which maintains a relatively constant concentration of dissolved powder concentrate maintained in the third fluid conducting means. Claims 5, 6, 11, 24, 25, 28, 35, 77, 78, 79 and 80 326 The respondent put no submissions of anticipation in relation to these claims. The applicants filed submissions. Broadly speaking, they are either dependent or contain integers otherwise not anticipated by the Alza Patent: the absence of a measuring means comprising a conductivity measuring device, the absence of identification of particle size of powder, the absence of an integer dealing with the amount of bicarbonate being between 400 to 900 grams, the absence of a measuring means, the absence of a measuring means located in the first fluid conducting means, the absence of a measuring means located in the first fluid conducting means downstream of the mixing point, the absence of flow regulating means located in the third fluid conducting means and the absence of such a flow regulating means being responsive to a measuring means. Claim 88 327 The respondent submits that this is anticipated insofar as it is additional to claim 4 through claims 28 to 30. All the features of claims 28 to 30 are not present: see above. I do not repeat what I have said about water or teaching away from saturation. 328 In my view Alza does not anticipate. Fair Basis, Sufficiency and Utility 329 The second further amended particulars of invalidity filed in July 2003 identify all three above grounds. Sufficiency and utility were the matters substantially pressed in address. 330 The basis of the particulars for each of the assertions (a) that there were claims that were not useful, (b) that the specifications did not describe the invention fully, including the best method known to the applicant of performing the invention, and (c) that the claims were not fairly based on the matter described in the specification was the same: the lack of inclusion of "measuring means" or "flow regulating means". 331 Dealing with sufficiency first, the skilled addressee is the person in whose place the Court is to place itself in reading the specification and claims, that is, some person acquainted with the surrounding circumstances as to the state of the art and manufacture at the time: Kimberly-Clark at 16 [24]. The question is whether the disclosure will enable the addressee to produce something within each claim without new inventions or addition or prolonged study of matters preventing initial difficulty: Kimberly-Clark at 17 [25]. 332 I have already dealt with the evidence concerning measuring means and flow regulating means. The person skilled in the art who understood dialysis machines and their workings would have appreciated immediately that a fail safe measuring and by-pass system was essential, and that measuring systems governing flow regulating means were optional, depending upon the nature of proportioning devices were used. 333 Thus, even if claims 2 and 4 and dependent claims can be seen to exclude measuring means and flow regulating means responsive thereto, because of their presence in claim 1 and an exhaustive meaning of the word "comprise" (being a view, which I have earlier rejected) the person skilled in the art would still be able to produce within each claim, though not using a measuring means and a flow regulating means responsive thereto. 334 Nothing in the claims and specification teaches or requires that the claims exclude a measuring means and fail safe by-pass device. 335 As to utility, the respondent submitted that claims 2 and 4 and dependent claims do not provide sufficient information to perform the invention without measuring means and flow regulating means. The respondent relied on a part of Professor Coster's affidavit evidence that dissolution by percolation cannot reproducibly yield solutions of a specified concentration without some feed-back control system involving adjustment of the further dilution or adjustment of the percolation result. 336 There are two answers to this. First, as Professor Schindhelm said in his cross-examination, even if a fixed volume proportioning system were used one could rely on the fail safe and rely on the quality of inputs and achieve a satisfactory or working dialysis system. This was consistent with the evidence, including that of Professor Coster, that if water temperature is maintained at a constant level and the percolation column or fixed bed is appropriately arranged and the percolation process is arranged to be slow enough the solution emerging from the percolator can be made to be consistently saturated. 337 Secondly, I do not think that claims 2 and 4 and dependent claims exclude a measuring device and a flow regulating device responsive thereto and the specification amply describes how to make a system which does possess conductivity measuring means and flow regulating means. 338 As can be seen from the judgment of the Full Court in Abbott Laboratories v Corbridge Group Pty Ltd [2002] FCAFC 314; [2002] AIPC 91-824 [63]-[67], even if the word "comprise" does not have the wider meaning of include, that is not to say the skilled reader would not understand that to make the claim of utility some well known step need, or could, be taken. For the same reasons what is claimed, in the light of the specification in the hands of a person skilled in the art, is useful. 339 Fair basis was not pressed in argument. Nevertheless, I should deal with it briefly as it remained on the pleadings. 340 The particulars of invalidity were as follows: There is no support in the specification for any claim disclosing a dialysis system which does not include either "measuring means" or "flow regulating means". 341 The specification does however describe systems which do not expressly mention such means: p 4 ll 5 – p 4 ll 9; p 5ll 9 – p 5a ll 29; p ;5a l 30 – p 56 l 22. 342 Further, as I have already described, measuring means, flow regulating means and fail safe systems were well known as part of the prior art. There were fixed volume proportioning machines or conductivity measuring means and flow regulating means responsive thereto. 343 The evidence referred to above to the effect that the production of saturated solutions from percolation processes at a slow enough rate given a constant temperature underpinned the conclusion that the skilled reader with a knowledge of dissolution and mass transfer principles together with a familiarity with the prior art would understand the claims (other than those such as claim 1 specifically including them) to allow for the presence or absence of measuring devices and flow regulating means responsive thereto (though not for the absence of a measuring device associated with a fail safe by-pass) were both claimed and based on what is described in the specification. 344 I reject the claim that the claims were not fairly based, to the extent that it can be said not to have been withdrawn. Obviousness 345 The Second Further Amended Particulars of Invalidity under the heading "Inventive Step" were in the following terms: 2. The alleged invention is not a patentable invention in that, so far as claimed in each claim, it did not involve an inventive step as at the priority date. PARTICULARS 2.1 Hereunder the Cross Claimant will rely on common general knowledge in Australia as at the priority date. 2.2 Without prejudice as to the generality of 2.1, the Cross Claimaint will rely upon the publication in Australia before the priority date of each of the following documents: … (a) Gambro: "AK-10 System, Bicarbonate Monitor BCM 10-1" HC E-6410, Rev.05.1981; (b) Gambro: "AK-10 System, Bicarbonate Monitor BCM 10-1, Service Manual" HC E 6901, Rev. 05.1983; (c) Peter W Riebling: "Extraction and Extractives", Remington's Pharmaceutical Sciences, Fifteenth Edition (1975) pp 1443 and 1509-1522; (d) "Leaching", Perry's Chemical Engineer's Handbook, Sixth Edition (1984) pp 19-48; (e) Renal Systems Inc: Instruction manual – "Bicarb-o-mate – Haemodialysis Sodium Bicarbonate Proportioning System Model RS-8000," 1980. 346 The language of those particulars and in particular the mere identification of the publication in Australia of certain documents (without an assertion that they formed part of some identified common general knowledge) is redolent of the 1990 Act. However, whilst the Patents Act 1952 (Cth)(the 1952 Act) was repealed by s 230 of the 1990 Act, and if the Patent were to be revoked, it would be revoked under the 1990 Act, for the respondent to succeed it must do so on the grounds expressed in s 100 of the 1952 Act. 347 Section 100(1)(e) of the 1952 Act provided for the revocation of a patent on the ground that the invention so far as claimed in any claim of the complete specification was obvious and did not involve an inventive step having regard to what was known and used in Australia on or before the priority date of that claim. 348 It is the invention as claimed that must be obvious. Of course, reading and understanding the nature and essence of the claim may require recourse to the body of the specification: see [114] above; but once that is done, one looks (at least in the 1952 Act) to the boundaries of the claims to assess the obviousness or existence of the inventive step. 349 The reasons for stressing the importance of the invention as claimed are twofold, though related. First, the respondent, as earlier referred to often stressed the width of the body of the specification to identify the nature of the enquiry as to who was the relevant person or persons against whom to judge the obviousness of the inventive step. Secondly, both sides, but in particular the respondent, used the expression "the relevant skilled addressee" in the discourse in respect of obviousness. The respondent's witnesses, in particular Professors Schindhelm and Coster, after positing a skilled addressee, gave evidence of, amongst other things, what such a person would have found self evident as disclosed in the Patent. Both professors commented expansively (and at times inadmissibly) on the scope and meaning of the Patent and whether it was anticipated by one or more of Stasz, Mund and Alza. I will deal in more detail with their evidence in due course. It is sufficient to say at this point that the correct approach in assessing obviousness is to identify the invention as claimed and then to identify the person or persons who could be said to be the skilled but non-inventive person in the field. The "field" will be the "art" to which the invention as claimed relates. See generally Wellcome Foundation v VR Laboratories (1981) 148 CLR 262, 270; the 3M case at 293; Sunbeam Corporation v Morphy-Richards (Australia) Pty Ltd (1961) 180 CLR 98, 112; and Minnesota Mining and Manufacturing Co v Tyco Electronics Pty Ltd [2002] FCAFC 315; (2002) 56 IPR 248, 257 [38] (3M v Tyco). 350 The invention as claimed involved a system, and an article for use in a system, for preparation, or for use in preparation, of dialysis or replacement fluid or a component fluid thereof by mixing at least one concentrate in powder form with water. As I have earlier stated, the claims, when read with the body of the specification in the knowledge of the prior art, teach that this system is for the production continuously and on-line of the dialysis or replacement fluid, thus, overcoming the various problems of pre-preparing sodium carbonate concentrate solution before use in treatment. 351 The claims, set against an understanding of the prior art and the teaching in the body of the specification are for an asserted improvement to the design and operation of dialysis machines. The improvement, as claimed, involved a system, and an article for use in a system, dealing with the dissolution of powder in water or water based fluid to form a concentrate solution on-line to be mixed into a flow of water by the types of well-known proportioning machines. Instead of a pre-prepared 10 litre bottle of solution, a vessel containing powder concentrate was to be placed into the hydraulic circuit of the machine and principles of dissolution used to create a satisfactory concentrate solution by passing water into the vessel and withdrawing solution therefrom. 352 The applicants in their written submissions put that the invention (in the sense of the inventive step or inventive act being the intermediate sense discussed by Fletcher-Moulton LJ in British United Shoe Machinery Co Ltd v A Fussell & Sons Ltd (1908) 25 RPC 631, 651 or the third meaning referred to by Mr Blanco White QC in Patents for Inventions (4th Ed, 1974) [1-201-33] referred to in Kimberly-Clark at 14-15 [19] – [21]) was as follows: (a) the appreciation that the problems with preparation of batch concentrates of sodium bicarbonate should and could be addressed; (b) the conception of the idea that it would be advantageous to mix sodium bicarbonate powder concentrate with water at the point of treatment; (c) the conception of the idea to produce liquid bicarbonate concentrate solution "on-line" from dry bicarbonate powder during treatment, in particular, the conception of the idea to use the hydraulic circuit of a proportioning dialysis machine to do this; and (d) achieving this in existing dialysis machines by integrating the production of a solution within a continuous fluid flow path (ie the combination of integers employed to implement the idea). 353 In so expressing the matter, the applicants emphasised that the inventive step or element to sustain the patent may be small – the scintilla of inventiveness: Woolworths Ltd v WB Davis and Son Inc (1942) 16 ALJ 57, 59; HPM Industries Pty Ltd v Gerard Industries Ltd (1957) 98 CLR 424, 436; Meyers Taylor at 249; Aktiebolaget Hässle v Alphapharm Pty Ltd [2002] HCA 59; 194 ALR 485, [48] (the Astra case); and Allsop Inc v Bintang Ltd (1989) 15 IPR 686, 701. Also, and most importantly, the applicants stressed the need not to break up the conception of the idea and its practical embodiment, that is not to divide up the inventive process. Reliance was placed in this regard on what was said by Dixon CJ, Kitto J and Windeyer J in National Research Development Corporation v Commissioner of Patents (1959) 102 CLR 252 at 264: …The truth is that the distinction between discovery and invention is not precise enough to be other than misleading in this area of discussion. There may indeed be a discovery without invention – either because the discovery is of some piece of abstract information without any suggestion of a practical application of it to a useful end, or because its application lies outside the realm of "manufacture". But where a person finds out that a useful result may be produced by doing something which has not been done by that procedure before, his claim for a patent is not validly answered by telling him that although there was ingenuity in his discovery that the materials used in the process would produce the useful result no ingenuity was involved in showing how the discovery, once it had been made, might be applied. The fallacy lies in dividing up the process that he puts forward as his invention. It is the whole process that must be considered; and he need not show more than one inventive step in the advance which he has made beyond the prior limits of the relevant art. This is perhaps nowhere more clearly put than it was by Fletcher Moulton LJ in Hicton's Patent Syndicate v Patents and Machine Improvements Co Ltd (1909) 26 RPC 339 when he said of Watt's invention for the condensation of steam, out of which the steam engine grew: "Now can it be suggested that it required any invention whatever to carry out that idea when once had got it? It could be done in a thousand ways and by any competent engineer, but the invention was in the idea, and when he had once got that idea, the carrying out of it was perfectly easy. To say that the conception may be meritorious and may involve invention and may be new and original, and simply because when you have once got the idea it is easy to carry it out, that that deprives it of the title of being a new invention according to our patent law, is, I think, an extremely dangerous principle and justified neither by reason nor authority" ((1909) 26 RPC, at pp 347-348). 354 This approach is to be steadily borne in mind in this case. Once conceived and implemented, the system used no new principle. Basic chemical engineering principles governing dissolution were called in aid by the respondent and its witnesses to show the simplicity and to assert the obviousness of the system, as claimed. But that, it seems to me, is to risk denying the totality or wholeness of such inventiveness as there may have been; it is also to risk error by starting with the system as claimed and asserting from that endpoint that the claim is obvious – the well known warnings against the seductive clarity of hindsight (Graham Hart (1971) Pty Ltd v SW Hart & Co Pty Ltd (1978) 141 CLR 305, 332; Wellcome Foundation Ltd v VR Laboratories (Aust) Pty Ltd at 286) are less likely to be heeded if one divides up the inventive process, takes the system as claimed and emphasises the well known character of the principles of chemical engineering employed to make the system effective. 355 With the invention as claimed understood against the background of the prior art and the teaching of the body of the specification, the relevant field or art is the design or improvement of dialysis machines or systems for which the system and article as claimed are said to be improvements. 356 The applicants put Mr West and Ms Yuill forward as persons skilled in the relevant art against which to judge obviousness. Certainly, as to what was known or used by those at the Priority Date who used, maintained and at times adapted such machines, Mr West and Ms Yuill were of great experience, knowledge and competence. Neither, however, was charged with making design improvements to such machines. Each, in his and her own sphere of work, took what the designers and manufacturers provided, understood and employed the workings of such machines. The evidence of both is, however, invaluable as to the workings of the prior art, its limitations, difficulties and characteristics. I will deal with various outstanding paragraphs of their evidence admitted subject to objection later in these reasons, I would simply say at this point that the lack of background and understanding of Mr West in and of scientific principles, in particular chemical engineering, in his cross-examination (and indeed avowedly in his own affidavit evidence) reflected the limitations of the use of a dialysis technician (however well skilled in that field) as the relevant skilled worker. 357 The relevant skilled worker against which to judge the inventiveness or not of the invention as claimed is the person or persons designing and improving dialysis machines. No company designed or manufactured such machines in Australia at the Priority Date. Professor Schindhelm, however, was part of an eminent and highly qualified group of people at the Centre for Biomedical Engineering at the University of New South Wales, which was a multi-disciplinary team actively involved in research into dialysis systems and therapies. The nature of research carried out by this group from 1976 to 1983 was set out in exhibit KS-16. The direction of the research was significantly towards therapeutic improvements; though, that said, it involved "treatment modalities" since the therapeutic benefit of the treatment is not easily divorced from practical applications of the efficient workings of the machines. The workings and improvement of machines involved an understanding of mechanical or fluid engineering, chemical engineering, electronics, membranes and medicine. Professor Schindhelm was eminently qualified to speak of chemical engineering principles in a biomedical context. Professor Schindhelm was a professor of biomedical engineering, with a doctorate in chemical engineering. 358 Professor Schindhelm also had direct experience in the period 1980 to 1983 working with dialysis machines and commercially available dialysis fluids. He also operated and supervised the operation of basic dialysis procedures and was familiar with the technical operation of dialysis machines. During this period he had contact and engagement with dialysis technicians and nurses. 359 I accept that Professor Schindhelm was in a position to speak as someone in the relevant field. Even though no manufacturer was located in Australia, the Centre at which Professor Schindhelm worked was in the field of making improvements including those of the kind claimed in the Patent. Perhaps the only qualification to his evidence was his apparent capacity for invention. 360 Professor Coster, who was called by the respondent, did not have a background close to the development of haemodialysis systems. He was a professor of physics, who in 1986 founded the department of biophysics at the University of New South Wales. He has worked extensively in the field of membrane science and cells. He is a person of proven and remarkable inventive skill in these areas. Though being amply qualified, in one sense, to discuss the scientific principles at work in a dialysis machine and the system and article as claimed, he is not someone able to give any real insight into the approach of the skilled and non-inventive designer and improver of dialysis machines and systems as Professor Schindhelm was. Nevertheless, he was in a position and qualified to discuss the principles operative in respect of dissolution, percolation and like matters. 361 Dr Davies, who was called by the applicants, was a chemical engineer. He was called by the applicants to show the difficulties of problem solving in this area. His background in chemical engineering (though he was called by the applicants) reflected an attempt to meet what the respondent's evidence appeared to say from the perspective of a chemical engineer: that the dissolution principles were well known and the "advance" obvious. Though not working in the field of dialysis at the time, he was given a clear understanding of the prior art and its problems. He was asked to make improvement to the art to overcome the problems. He was not told about the Patent. 362 The role of principles of chemical engineering assumed some prominence in the evidence and debate: in particular the principles governing dissolution, percolation and leaching. That this was so is, in one sense, only to be expected, since once the conception of the idea set out at [352] above is recognised to solve problems of preparation of batch concentrates of sodium bicarbonate, the principles governing the dissolution of a well known powder solute are themselves fundamental and well known. 363 I have set out earlier in these reasons the state of the art, and the problems inherent within it. As Dr Davies said in cross-examination, if improvements were to be made, one problem that needed addressing arose from the diseconomies, inconveniences and associated problems of preparing and transporting bulk material. He agreed that the recognition that the bulk, that is the water, needed to be got rid of, came to him fairly quickly and without difficulty. The respondent says that the inventive step elucidated at [352] above, was thus plain or obvious. There are at least two problems with this assertion. First, an understanding of what Dr Davies did to carry out or effectuate the realisation tends against the proposition that what he fairly quickly understood was the elucidated invention. Secondly, the principles of chemical engineering concerning percolation did not tend to teach in the direction of the claimed solution. 364 I will come back to Dr Davies' "inventive processes". Professors Schindhelm and Coster gave much evidence as to the principles of dissolution and percolation. I accept that the chemical engineering principles there involved were fundamental and were part of the common general knowledge of a person or persons seeking to develop improvements to a dialysis machine or system in the respects claimed in the Patent. An undergraduate text such as Perry's Chemical Engineer's Handbook (6th Ed, 1984) can also be accepted to be part of the common general knowledge of such a person. On the other hand I am not persuaded that Remington's Pharmaceutical Sciences by Reibling (15th Ed, 1975) was part of such a person's common general knowledge, even if it were a book to which resort might be had by such a person with a chemical engineering background. It is not a standard engineering text. It is a text used in the formulation of pharmaceuticals. 365 Professor Schindhelm moved from the proposition that the principles of percolation are well known to the proposition that the step to produce a system using such principles was obvious. This does not follow at all, with respect. It is to use the well known nature of the general principles employed to carry out the idea, to conclude that the idea was obvious: cf National Research Development Corporation v Commissioner of Patents at 264; and Blanco-White Patents for Inventions (5th Ed) [4-218]. 366 That percolation is a well known principle can be accepted. However, what it is usually employed for is a more relevant enquiry to assess whether it was plain or obvious to take the step of employing it to improve dialysis systems. The usual employment of percolation (in fields such as mining) was to extract a soluble substance from a mixture of soluble and insoluble substances. That was the usual context for the process. Professor Schindhelm readily agreed in oral evidence that it was not usual to prepare a solution of a specific concentration by using a percolation process. Professor Coster at first in his cross-examination somewhat argumentatively and dismissively rejected this proposition. Later, however, when he resumed his cross-examination Professor Coster recanted that evidence and made clear that he was in the habit of using percolation as a method of dissolving powder, but not as a method of making up a solution of a given concentrate. (This part of Professor Coster's evidence, especially his early attitude to the issue just discussed, was a reflection, to a degree, of his approach to the cross-examiner, which I observed in his giving evidence. From time to time, he displayed a degree of combative advocacy which would lead me to place reliance on his evidence with a degree of caution. Professor Schindhelm, on the other hand, struck me at all times as overwhelmingly anxious in his oral evidence to ensure that questions asked of him were answered directly and without any hint of advocacy. A discourse of real assistance took place between the cross-examiner and Professor Schindhelm.) 367 The lack of usualness of using percolation to prepare a solution of a specific concentrate can be seen otherwise in Professor Schindhelm's affidavit evidence. In his second affidavit, Professor Schindhelm referred to cold percolation of sugar in making syrups referred to in Remington's. Remington's had been given to him by the respondent's solicitors. Professor Schindhelm readily acknowledged that in the five years that he had been involved in the legal case this was the first example that he had produced showing the use of the percolation process to dissolve a pure (and in the case of sugar, very soluble) solute. It did not come from the common general knowledge of the chemical engineer or the prior art. Further, it does not display what is claimed in the Patent. It shows the production of a syrup which is then built up to the correct volume. 368 Dissolution of a solute by passing water over the solute can produce an emerging solution relatively constant in concentration. However, the prior art and usual practice did not teach towards the preparation of a solution of a specific concentration by using the percolation process. 369 To the extent that some of the affidavit material, in particular that of Professor Coster, can be seen to express or contain the proposition that it was usual to produce a solution of a specified concentration by percolation, it must be read in the light of my previously referred to preference as to the oral evidence presented in this regard. 370 Dr Davies' evidence was illuminating in assessing whether the idea of the invention (as described at [352] above) was obvious. Dr Davies was not shown the Patent. He was given an accurate understanding of the state of the prior art. His chemical engineering background made him familiar with the principles of dissolution and percolation that Professors Schindhelm and Coster said made the invention obvious. Dr Davies was made familiar with the prior art, he was given written extracts of texts on the composition of dialysis fluid and proportioning and monitoring equipment, the manual for one of the applicants' machines and a flow diagram of other machines. He read and studied the material and was asked to develop or improve a system for preparing a dialysis or replacement fluid overcoming the limitations and disadvantages of the prior art. Limitations were placed on what he should refer to in order to ensure that he only examined what could be said to be common general knowledge. 371 His ideas and thought processes were discussed with one of the solicitors acting for the applicants and a transcript was made of these interviews. 372 The thought processes revealed by his evidence lead one to think that the Patent is not obvious. Dr Davies first thought of injecting carbon dioxide into bicarbonate solution; he suggested splitting the pH and made related suggestions as to the composition of the A and B concentrates. After some further thought Dr Davies thought of using solid form in a vessel. The transcript of interview recording discussion of this suggestion was as follows: Well, it occurred to me that you could… One of the areas of making up dialysate concentrate in a ready to dilute form is a considerable amount of expense and it occurred to me that there would be a method by which you could cut this down by going back to a kind of solid form in which you present the salts, the various salts and the glucose in a solid form which was already inside a vessel, and the vessel was constructed in such a way that when you filled it up with the regular water supply, it came up to a level automatically and the addition of the water caused the salts to dissolve. You can imagine the water swirling around from pressure inside the vessel. Now this would cause it, this would lower the cost of transport and formulation considerably because you'd only be manufacturing a powder formulation – probably two powder formulations – you could get away with one possibly, but I'm inclined to think that you'd probably go with two, and having an automatic volume check on this system would mean that you could connect it up to a water supply for the dialyser and make your concentrate on the spot using the water supply as the dissolving, that is, the pressure and swirling that you could create in this vessel to dissolve in the solids. It wouldn't cut down the volume but it would cut down the weight, so I thought that might be a reasonable innovation. And I looked at the idea, mentally only I didn't have any notes, of concentrating the material further so that you'd get a highly concentrated solid, sorry, liquid solution, but again I had to reject that – I tried to figure out ways of doing it, but the solubility of sodium bicarbonate is just simply not enough and you can't use something that doesn't have sodium in it. You can't use potassium bicarbonate for instance because then you'd overload the potassium in the blood stream and that would, I don't know whether it leads to high blood pressure or low blood pressure, but it's not good. The body likes certain defined limits of these salts and you can't go fiddling with them. So, I'm left with a solid formulation device which is in an automatic vessel… that's all I can come up with I'm sorry. 373 In cross-examination Mr Archibald QC, senior counsel for the respondent, sought to obtain from Dr Davies agreement that this critical concept involved including the vessel in the hydraulic circuit of an ordinary dialysis machine. The following exchange took place: Mr Archibald: So the concept is that all of this happens on the spot, really on or in the machine, is that right? Dr Davies: It happens in the vessel, yes. Mr Archibald: And the vessel will be on or in the machine? Dr Davies: It needn't be but it could be. Mr Archibald: Now, for all of that to work you would of course have, wouldn't you, various pipes and valves and pumps that would take the fluid forward? Dr Davies: You would. Mr Archibald: And what you would need to achieve that would simply be to draw upon the ordinary hydraulics mechanisms that would take the fluid through the machine? Dr Davies: Yes, it's a way of making up the liquid concentrate by a different method. Mr Archibald: But there's nothing in the pipes and the valves and the tubes that's any different or involves any development in that respect? Dr Davies: No, the point being to replace the current system with something, self-contained, that would be compatible with the existing setup. Mr Archibald: And if all of that is being done as at, say 1987, again the hydraulics won't be any different from what they would otherwise have been? Dr Davies: They wouldn't be. 374 These questions were asked of Dr Davies largely in the present tense. By this stage Dr Davies was familiar with the Patent. Looking at what he did contemporaneously, it is tolerably clear that what Dr Davies was thinking of here was somehow mixing the powder at the site of the machine in a vessel. The contemporaneous transcript does not disclose the use of the vessel of powder within the hydraulic system of the machine in the manner disclosed in the Patent. As he says, he tried to figure out ways of doing it, but the low solubility of sodium bicarbonate brought him back to other possibilities. This low solubility together with the dissolution in the vessel by pressure and swirling of water lead me to conclude that he was considering on site preparation, somehow automatically, of a batch of solution ("it came up to a level automatically"); but that reducing the volume of this mixture was defeated by the low solubility of sodium bicarbonate. 375 What Dr Davies was thinking at this point was clarified by the transcript of interview of discussion on the following morning. That discussion made clear that he was referring to mixing water in 5, 10 or 20 litre carboys, which already contained salts. He said the following: …The idea here was that you supplied to the user, the purchaser would buy a vessel but it had no water in it, and what you did … but it did have the salts present in some sort of quick release form. They could be in an envelope that dissolves in the water, some sort of automatic dispensing system, not vastly different from say dropping an Aspro in water and causing it to automatically dissolve. But in this case, I thought that what we do is cut down the weight of these things by leaving out the water and including the dry salts, then it would have some clever sort of automatic system in it that had… you would plug in your water to some sort of stopcock or connection of some sort, you'd connect it up, turn the water on and when it filled the vessel, it would automatically stop and the action of the water flowing into the vessel would swirl and mix the contents until you had a 5, 10 or 20 litre carboy already filled with concentrate ready to go and that was another idea that I had – to cut down the weight but not the volume of goods transported. So the volume of the vessel would be the same, but the weight would be a lot less and this might be an advantage… I can see maybe in terms…of transport and delivery and manufacture, it should cut down costs. Unfortunately it's the same volume as before, so it would just occupy as much space in the warehouse, so there wouldn't be an advantage there. But it would involve some clever technology built into the vessel so that it filled itself automatically and dissolved the contents. … [I]t would rely on the flow of the water itself to make it work, a bit like the way a garden hose timer works. … In the vessel is no water to start with. It's supplied by the manufacturer as an empty vessel containing the solids in some sort of form that easily dissolves in water when the water hits it. As I say, the presentation of the solids could be in a dissolving envelope for instance, could be present in pills for instance, or tablets should I say, that dissolve when they hit the water a bit like an Aspirin tablet that contains bicarbonate and citric acids for instance and automatically dissolves. Aspro, Disprin etc these are formulations that dissolve. … [S]o I like that idea a lot and I think keeping them as separate concentrates is good and this means that we can have a concentrate or automatic concentrate preparation system where all you do is connect this 5 or 10 litre vessel up to the water supply, open or press a valve, open a valve or create the start conditions in some way, I can't visualise it just yet, and it automatically fills the vessel to the required point and dissolves the solids within the vessel at the same time. And you'd do that for solution A and solution B separately and when that's done, you've got your concentrate ready to use. 376 The schematic representation of this in WAD 41 makes this powder dissolution idea clearer: WAD 41 377 The essential nature of this as a batch device was recognised by Dr Davies in cross-examination: Mr Archibald: And that could operate continuously in line? Dr Davies: Once it has been prepared it's a batch device, in as much as once it is filled, automatically taking itself to the right level, it is then placed as a supply of batch concentrate, so it's not strictly a continuous process because that would imply it has no beginning and has no conceivable end, but this one has an end because it has capacity. Mr Archibald: But in conjunction with the reservoir you have described before, it operates - the fluid supply is continuous? Dr Davies: The fluid supplied to this vessel terminates at some volume. It may be, for argument's sake, a 20 litre vessel and that then allows you to run your plant continuously until the termination of that vessel's contents. Mr Archibald: Thank you, and your diagrammatic representation on that page and the tab 41 is for the A concentrate, is that right? Dr Davies: Yes, it is. Mr Archibald: But you note at the foot that a similar carboy would be used for the B concentrate? Dr Davies: As I saw it, yes. 378 That he was not thinking of a vessel with powder placed into a hydraulic system as claimed such that a continuous stream of concentrate solution is withdrawn from the vessel to be taken to and mixed at a point in a first fluid conducting means can be seen from his direction from this point. He next thought of a paste of sodium bicarbonate thickened and lubricated with a polymer. The paste would be metered out into a stream of diluted A solution. The contemporaneous material of Dr Davies (in particular, exhibit WAD 36) together with his cross-examination (Tp 217 ll 21-23) reveal some form of mixing device to mix the B paste with the diluted A solution. 379 Dr Davies also thought of micro-encapsulating the salts of concentrate A and feeding them in to a suspension. 380 Dr Davies also thought of making up the A and B salts in separate tablet forms and, by an automatic dispenser, releasing them into a mixer vessel that fills with water, there to be dissolved. When dissolution took place, the concentrate solution was to be sent to a storage area and the process repeated. This was a series of batch preparations. This can be seen from the contemporaneous notes and contemporaneous transcript of interview. In exhibit WAD 33 Dr Davies wrote: Suppose that we made the salts up in tablet form. Tablets of salts and glucose (for solution A) could be made to high formulation tolerances so that each tablet contained the same amount of material with only slight variation. Each tablet might contain slightly more than e.g. 10 grams of material which would be enough for about 1 litre of working strength solution. (Note this might work better or equally well if a concentrate is made from the tablets. Needs to be optimised). A sequence of batch operations is now joined to give a continuous operation. The tablets are used to make up a working strength solution according to a program. A given number of tablets is released from an automatic dispenser into a mixer vessel that fills to a pre-programmed height with water. An integral mixer stirs the whole for a preset period after which time the tablets are dissolved. At this point a valve opens and the new solution in the vessel are dumped into the main storage vessel from which the pump takes WS solution to the dialyser. The progress of this automatic formulation vessel is somewhat faster than demand so that the solution can always keep up. The process simply repeats itself as required. Bicarbonate could be dissolved in the same way but it might be better to add bicarbonate tablets in a sequence to the working strength A solution once the A solution is fully dissolved. A pH controller could be used to meter in the tablets. [bold in original; underlining added] 381 The transcript of interview at pp 266-67 of exhibit WAD 35 clearly reveals the preparation of batches of concentrate solution being fed into a reservoir of working strength solution. Dr Davies drew a schematic drawing of this invention being exhibit WAD 37 which was as follows: 382 Next, Dr Davies was provided with a copy of Perry's Chemical Engineers Handbook (6th Ed, 1984) and invited to consult it for ideas. Dr Davies was familiar with the book. Dr Davies was deliberately prompted by the solicitor as to the temperature monitoring by reference to a section in a standard text on that topic previously given to him. He reviewed the various ideas that he had thought of by this time: bicarbonate paste, micro-encapsulation of salts and dextrose for solution A, formulation of solution A and B from tablets, and the automatic formulation carboy. The latter two were described at this point as follows in exhibit WAD 48: 2.3 Formulation of Solutions A and B from tablets My suggestion is for semi-continuous automatic formulation of either: (i) A and B concentrates in situ or (ii) working strength dialysis solution. I may not have included suggestion (ii) in previous reports but I am doing so now. 2.3.1 Concentrates. The production of concentrated A and B solution could have a desirable influence on the existing dialysis plant's temperature control. Concentrates could be made up with a stream of make-up water that was previously adjusted to the right temperature range (36 to 42 deg C). Doing this rather than say using ambient temperature water would be an advantage because the tables would dissolve more quickly. Once dissolved the concentrates would be stored for as much time as needed before they were used up and in this relatively short time they would still remain warm. Temperature control after dilution would be improved because the concentrates were already near to the correct temperature. 2.3.2 Working strength. In this case the working strength solution is made semi continuously from tablets using a mixing vessel used to dissolve the tablets. The set up would be similar to that in (2.3.1) above but the mixing vessel would be larger. In this case the temperature of the make-up water would be adjusted before adding the tablets. This is the preferred mode given the concerns about salt water corrosion of parts. As such the effect on temperature of the mixing and dissolution of the tablets would be minimal. However large volumes of solution are involved and these will be held for longer periods of time. Longer periods of time allow for greater cooling of the solution. I would expect this mode to be less attractive, with respect to temperature control, than the method (2.3.1) above. 2.3.3 Automatic Formulation Carboy The idea here is for a carboy fitted with a cistern valve to allow partially automatic formulation of concentrated stock concentrates A and B. Given that these solutions would effectively resemble concentrated stock solutions are purchased from a supplier, I can see no important influence on temperature control in this case. [emphasis in original] 383 Dr Davies was then provided with further materials and invited to consult them for ideas. These materials concerned liquid/solid extraction and leaching. After reading these for nine hours, Dr Davies at first could not see their relevance. He said in cross-examination, which I accept, that at first he was bewildered by them (that is, as to their relevance). However, they then did stimulate some ideas. These new ideas were described in the transcript of interview as follows: Now what I've done here is I've modified a previous idea of using tablets and this time instead of going to a concentrate I'm going direct to working strength solution and I've thought about the concepts. Leaching is the science, the art, of dissolution of solids away from an insoluble material often called gangue in the mineral industry g-a-n-g-u-e which is the insoluble component. So this made me think well if we dissolve tablets in a flowing stream we can do this in a continuous process and make a working strength dialysis solution of the right formulation, the right composition, the right temperature and the correct PH. All of this can be done from tablets instead of from bulky concentrates. 384 The further ideas that he had were set out in two handwritten diagrams dealing with elutriation and hydrocyclone. Using these methods his idea was to drop tablets in a flowing stream of warm water. Dr Davies explained these ideas in exhibit WAD 54: 1. Tablets would be dissolved in a flowing stream of previously warmed water. Two ways of doing this effectively are 1. Elutriation. The phenomenon relies on the balance of downward force of gravity and the drag forces created by the upward movement of water. This is done in a vertical often conical vessel that is arranged with a small cross section at the bottom and the large cross section at the top. Water enters the vessel at the bottom and flows vertically. As the water rises in the vessel its upward velocity falls if the nett flowrate is constant. Tablets dropped into such a vessel will fall to the bottom and here they will meet the upward flow of water. As they dissolve in the water, the tablets become even smaller. These are known as "shrinking particles". As this happens the diameter of the shrinking particles falls and their sedimentation velocity falls also. This allows them to be carried upward by the upward flow of water. The particles tend to reach a level in the elutriation vessel that is a function of their size only. Properly designed the particles can be held within the vessel until they are entirely dissolved. This allows pure solution with no solids to be carried to the overflow of the vessel. 2. Hydrocyclone. Another device that works in a similar way to elutriation is the hydrocyclone. This device is designed to create a strong swirling action in a typically conical and cylindrical vessel. Water enters tangentially into the vessel and leaves by a central "vortex finder". The strong swirling action creates centrifugal force that tends to drag the particles to the outer wall of the vessel while an inward flow and drag force is created by the nett movement of water. The two forces can balance exactly and in this case, the particles will be forever trapped inside the hydrocyclone. However, if the particles are continuously dissolving in the water they will necessarily get smaller and they will move towards the vortex finder. Properly designed the hydrocyclone will dissolve all of the tablets and no solid will be present in the solution that enters the vortex finder. The desired results is that solid tablets and water enter the hydrocyclone and solution only exits. Overall these two systems elutriation and hydrocyclone are variants of the same thing i.e. a continuous dissolution device. 385 His explanatory diagrams were exhibits WAD 55 and WAD 56 as follows: 386 Dr Davies made clear in cross-examination, as is apparent from the above descriptions, especially the diagrams, that neither of these ideas was a fixed bed system, that is one involving percolation. Each, however, is an on-line system, rather than a batch preparation system providing solution to a reservoir. It is also to be noted that the written material to which Dr Davies was directed contained a number of counter current elutriator devices and a hydrocyclone. 387 In the days following the expression of these ideas, Dr Davies worked on further developments. One group of documents (exhibits WAD 59, WAD 60 and WAD 61) reveals that Dr Davies worked on the development of an automated continuous formulation plant for concentrate solutions of A and B concentrate and a hydrocyclone unit. 388 The automated plant was depicted in the following diagram: WAD 60 389 Thus, Dr Davies, over a period of a week, came up with and developed the following ideas: (a) dry salts dissolved in a 5, 10 or 20 litre carboy to be filled with water; (b) a bicarbonate paste injection; (c) micro-encapsulation of a A concentrate salts; (d) dispensing salts in tablet form into a mixing vessel for transfer to a reservoir or if a larger vessel was used the process could be semi-continuous; (e) in-line systems using tablets and elutriation and a hydrocyclone, and using the former method to develop a continuously operating plant. 390 The thinking of Dr Davies exposed a number of elements inherent within the claims and within the steps described at [352] above: first a recognition that the bulk was water and to take that out would solve the weight problems in transportation; and, secondly, a recognition that a method of mixing water with solid form (powder or tablet) of the concentrate was required. All his attempts worked around the appreciation of these considerations. Leaving aside (b) and (c) above (the micro encapsulation of the A solute and the bicarbonate paste) the ideas brought forward were either a device for preparing batches of concentrate: (a) and (d) above, or for continuous in-line mechanisms of greater complexity than the patent: (e). 391 Whilst Dr Davies wrestled with the elements of the problem and with ideas that reflected aspects of the resolution claimed in the Patent, he did not, after a week, come to what the respondent says was the obvious answer exhibited in the claims (even broadly expressed as in claim 1, leaving aside for the purposes of this discussion the measuring means and flow regulating means). He was not led directly to an improvement which was a system comprising a source of water, a vessel containing powder, a first fluid conducting means, a second fluid conducting means introducing water into the vessel containing the powder, a third fluid conducting means conducting concentrate solution from the vessel to be mixed on line with fluid in the first fluid conducting means; or a system otherwise described in the claims. Not only was he not led directly to it, he did not come to it over a week's consideration. 392 It is appropriate, at this point, to say something of the process in which Dr Davies was involved. There was a degree of artificiality and constraint to the process. Nevertheless, in circumstances where the claimed inventive step is the conception or idea, as earlier identified, which is said to be obvious or plain to someone with Dr Davies' chemical engineering background, there is a certain illumination gained by seeing the intellectual process directed to the problem and not going directly to the claimed solution. Whilst some constraint was imposed on Dr Davies, he was not deprived of the chemical engineer's basic principles and common general knowledge which the respondent said made the inventive step behind the claims, and so the Patent, obvious. 393 A greater "problem" than the constraint was the natural human urge described by Dr Davies to second guess his questioners whom he knew were (for their own proper reasons) keeping the context of his endeavour secret from him. When he was given the material on leaching, apart from being initially bewildered as to why it was being given to him, Dr Davies began to ask himself why the solicitors were providing it. He said the following in re-examination which I accept: Mr Catterns: Just apropo of Perry did you need access to Perry to have knowledge about leaching and percolation? Dr Davies: No, hardly anything. The point about those documents, it was what is going on in the mind of my immediate client at Blake Dawson and Waldron. Why are they are thinking that. So, I was actually thinking in behind what were they doing in order to present with these documents. Not that, ah, now I have these documents I will think about leaching. I was trying to out-think what they were trying to do. I perhaps shouldn't have done this but I couldn't help it. You know, I play chess and things like that so you naturally try to think what is the move that is going on behind the move. 394 Leaving aside this difficulty, no real impediment was placed in Dr Davies' path of immediately recognising the "obvious" improvement of introducing water into a vessel containing powder and withdrawing a solution of a given concentration employing percolation or leaching principles. 395 The Full Court in 3M v Tyco said the following at [45] and [46]: [45] The manner in which the evidence of some of the experts in the present case was bought into existence suggests that relatively little weight should be given to certain of that evidence. For example, witnesses were provided with a copy of the Patent. They were either provided with a large number of other documents or found them in response to the task that was set them. That is hardly calculated to result in objective evidence as to what the hypothetical uninventive but skilled worker would have done. To give the Patent to a prospective witness is tantamount to leading the witness. Further, unless the other documents were part of the common general knowledge in Australia before the Priority Date, they are not relevant to any question of obviousness. [46] Evidence by "experts" on the question of obviousness it is not always likely to be helpful (see Firebelt Pty Limited v Brambles Australia Limited [2002] HCA 21 at [46]). Indeed, where evidence is obtained in circumstances such as just described, the evidence is not likely to be helpful at all. 396 What might be said to be the risks alluded to in 3M v Tyco in showing the patent in suit to the expert (and, as here, commenting comprehensively on construction, infringement and novelty issues) are heightened where what is involved is the conception of an idea which involves, as it turns out, well known principles. It becomes very difficult (knowing the answer) to throw off the apparent importance of the well known principles to explain the answer provided by knowledge of the patent in suit. The difficulty of the artificial "constraint" which Mr Archibald put to Dr Davies is, it seems to me, dwarfed by the difficulty of looking forward at the Priority Date shorn of the knowledge of the Patent, if one knows of the Patent. The assessment of the obviousness of the conception of an idea is, at that point, compromised by knowing the answer. This is particularly so if, as here, the principles, which explain the successful implementation of the idea, are well known. See generally the Astra case at [21]. 397 Whatever its inherent faults through a certain artificiality or constraint, in circumstances where the inventive step is a conception of some simplicity, the process undertaken with Dr Davies can provide (and did provide here) real illumination. 398 Whilst Dr Davies was not someone involved in the development and design of dialysis machines, he carried the expertise (chemical engineering) which the respondent asserted was the discipline which would display the obvious character of the invention. He was satisfactorily apprised of the prior art. 399 Dr Davies' evidence was, in my view, powerful evidence against the conclusion of obviousness. 400 I do not think that the evidence of Professor Coster or Professor Schindhelm is sufficient to outweigh the effect of Dr Davies' evidence. There are a number of problems with their evidence. 401 First, each was inventive in his own right: cf Aldous J (as his Lordship then was) in Chiron Corporation v Organon Teknika Ltd [1994] FSR 202, 218-9. Though, of course, this did not disqualify them from giving evidence, it is to be borne in mind when the assessment is of the skilled but non-inventive worker. 402 Secondly, though each had background in relevant disciplines (Professor Schindhelm more so than Professor Coster) the difficulty in saying what would have appeared obvious or self-evident to a person or persons undertaking a relevant task (attempting to improve some technically practical aspect of a dialysis machine) was compounded by the passage of time – 1987 being the Priority Date. Though, it should be said, as Dr Davies recognised, once the idea was present, the principles and dissolution techniques involved had been well known for decades. 403 Professor Schindhelm was provided with the Patent at the outset. There was some confusion in the evidence as to what Professor Schindhelm looked at in coming to his views on obviousness . In his affidavit ([17] and exhibit KS 4) Professor Schindhelm stated that he was provided with Stasz and Mund for the purpose of giving his opinion on the validity of the invention claimed in the Patent. In cross-examination, (at Tpp 301-302), however, he said he saw Stasz and Mund after formulating his opinion on obviousness. Stasz and Mund were not shown to be part of the common general knowledge. Whilst I accept, without hesitation, the truthfulness of this evidence in cross-examination by Professor Schindhelm, his opinion was formed with the Patent in mind (that is, knowing of the claimed development) and the knowledge of material not part of the common general knowledge, though gained after first formulating his view, could only go to reinforce a view reached with the compromising effect of the knowledge of the Patent. This problem of disentangling consideration of material not shown to be in the common general knowledge is best exhibited by [98] of his first affidavit where Stasz and Mund are used as reinforcement for a conclusion of obviousness which begins from an appreciation of the patentee's claimed improvement to solve a pre-existing problem: In view of the well known principles of percolation which I have just described, if confronted with the perceived problems which the Patent purports to solve (see paragraph 38 above), I believe that as at the Priority Dates, the Hypothetical Addressee would have found to be self evident and have adopted the solution reached by Gambro in the patent (that is, passing water through a container holding the sodium bicarbonate in powdered form in order to produce an effluent stream from the container which has a relatively constant concentration). I am supported in this view by the fact that a number of other people working in the dialysis field prior to the Priority Date, including the inventors of the Stasz and Mund Patents, reached the same conclusion well before the Priority Date to produce a dialysis solution by adding water to powdered concentrate in a vessel. 404 Professor Schindhelm was also given a copy of Remington's Pharmaceutical Sciences. This too was not shown to be common general knowledge of the relevant chemical engineer. Remington's itself stated that it was a textbook and reference work for pharmacists, physicians and other medical scientists. Professor Coster said that the book was directed to chemical engineers. He is not a chemical engineer, though he is an eminent scientist. I accept that it is a work which a chemical engineer would find of utility. Nevertheless, Professor Coster's answer in cross-examination does not establish that Remington's was part of the common general knowledge of the chemical engineer, or the person involved in designing or improving these machines who had a chemical engineering background. It was one of the documents given to him to help him assess the validity of the invention. 405 Professor Coster likewise was provided with the Patent and Remington's and the Alza Patent (which also was not shown to be part of any relevant person's common general knowledge). Professor Coster said that he also looked at several patents related to Alza. These were not shown to be part of any relevant person's common general knowledge. 406 Professor Coster also conducted unspecified searches in the library "on related subjects". He was also provided with some documents, otherwise unidentified. 407 The evidence of both Professors Schindhelm and Coster suffered from defects referred to in 3M v Tyco at [45], in particular in relation to both, the provision of the Patent. 408 To the extent that the evidence of Professor Schindhelm was in terms or in substance to the effect that the changes made by the Patent to existing systems was not inventive, I think that evidence must be set against his agreement that the use of percolation to obtain a solution of a given concentration was not usual, and also be set in the light of the compromising effect of knowing the patentee's claims and of absorbing similar conceptions of other patents not shown to be part of the general knowledge. These factors explain his fundamental reliance upon the well known dissolution principles of percolation to answer the antecedent and different (though related) question of the inventiveness of the idea of bringing those principles into play. He was given that answer. Thus, he, naturally, tended to emphasise the well known principles to explain it. 409 Professor Coster, as I have said, did tend to advocate the respondent's position. I approach his evidence with a modicum of caution. Professor Coster sought in his affidavits to describe known methods of preparation of dialysis fluids as including the use of methods which could be said to reflect the percolation process feeding concentrate solution into a stream of water (see [28] of his first affidavit) and [18] of his second affidavit). 410 In [28(d) and (e)] of his first affidavit he said: [28] In preparing the dialysis fluid for use in haemodialysis, the aim is to produce a stable, contaminant-free dialysis fluid with the concentration of the desired solutes in a tightly defined range. This can be achieved either by: … (d) by a process of percolation, where water is passed through a packed column to produce a stream of a solution containing the dissolved solute, the concentration of which can be adjusted by further mixing with a stream of water in a controlled manner (Method D); or (e) by withdrawing solution from a vessel containing a saturated solution of the solute and mixing this solution with a stream of water. The source of the saturated solution being maintained by the continuous or intermittent addition of water to the aforementioned vessel which contains an excess of the powder solute (Method E). 411 At best, this evidence can be seen as to how, with the benefit of the knowledge of the Patent, this could be done. The evidence of Mr West and Ms Yuill (and the lack of evidence to the contrary by Professor Schindhelm) was clear that the fourth and fifth methods identified by Professor Coster (methods D and E in [28] of his first affidavit and [18] of his second affidavit) were not used in the operation of the prior art. 412 Further, Professor Coster's accession (though not immediate) to the proposition that it was not usual to use percolation to obtain a solution of a specific concentration and the lack of any examples (other than the creation of sugar syrup) of use of percolation to dissolve a solute to create a solution sit uneasily with his statements that percolation and the withdrawal of a saturated solution from a vessel and the mixing of it with a stream of water would have been well known to someone in the field of improving dialysis systems. He was not in that field, and he was not a chemical engineer. His views may be seen to go beyond even those of Professor Schindhelm. To the extent that he was saying that a skilled but non-inventive person in that field would have been led directly by common general knowledge to use percolation and withdrawal of produced solution to place into a water stream, he perhaps can be seen as saying no more than Professor Schindhelm. Professor Coster's views are compromised by the matters which affect Professor Schindhelm's evidence, as well as the further unexplained material to which he had recourse, and what I perceived to be somewhat of a combative advocacy which he displayed. From the evidence of those with direct knowledge of how the art worked, and from the evidence of Professor Schindhelm with his deep experience in chemical engineering and his familiarity with dialysis techniques, I do not think it open to conclude that those engaged in the art (or those concerned with improving dialysis machines) used techniques, or would have thought it usual to use techniques, for the preparation of dialysis fluid with the concentration of the desired solutes in a highly defined range by the means described in [28(d) and (e)] and [18(d) and (e)] of Professor Coster's first and second affidavits respectively. To the extent that Professor Coster was seeking to say in these paragraphs or in evidence such as [33] to [38] of his first affidavit the same as Professor Schindhelm in the first paragraph of [98] of his first affidavit, I am not persuaded that that is reliable evidence to contradict the illuminating evidence of Dr Davies and the balance of the evidence. 413 In his third affidavit (dated 18 July 2003) Professor Coster said in [7] the following: In paragraph 28 of my First Affidavit I refer to five different ways by which concentrated fluids for use in dialysis may be prepared. Before the priority date I regularly used each of these methods for making up solutions and instructed students from time to time to use these methods, as appropriate. 414 Professor Coster accepted that method E ([28(e)] and [18(e)] of his first and second affidavits, respectively) was not used in relation to haemodialysis before the Priority Date. The example proffered by Professor Coster was described by him at Tp 344: Ms Howard: And you've given no examples of this being done? Prof Coster: In haemodialysis? Ms Howard: Yes? Prof Coster: No. It's a nice exercise for students which I used to set. If you haven't got a balance and you want a two molar solution of sodium chloride but you've got data, how can you do it? Well, one way of doing it is to get some water, chuck in an excess of sodium chloride, until it's saturated, then you can look up what that concentration is and then you know much to dilute it to get two molar, so you can do it without weighing. And it's a nice little exercise. 415 This, with respect, was neither method E nor the invention described and claimed. No other example was given. 416 Overall, the balance of Professor Coster's evidence was to the same effect as Professor Schindhelm's – that the basic principles were such that the step taken in the Patent to improve the dialysis system was self evident to the skilled but uninventive designer or improver of such systems. For the reasons I have given I do not find that evidence persuasive to outweigh Dr Davies' evidence. 417 The problems involved in the use of B concentrate had been evident for decades. They resurfaced in the early 1980s when the use of acetate alone became a problem for clinical reasons. The priority date is February 1987. There is no evidence before me upon which I can conclude that the design of the system, once the conception of the use of powder in a vessel on-line was made, would take very long. Indeed the evidence of Professor Schindhelm and Professor Coster would indicate that the fundamental principles were basic. If the conception was obvious and the principles to put it into effect basic, no explanation was given of why no person had redesigned dialysis machines before to employ such a system. The difficulties of B concentrate were well known. As Professor Schindhelm said the solution of the Patent was "very nice". He accepted that it was a simple, effective and efficient solution to the problem. The evidence permits the inference of the presence of commercial organisations interested in improvements to such machines. Years passed from the re-emergence of the use of B solution and its attendant problems, to the Priority Date. 418 The approach of the respondent must be set in this context. That approach was to analyse the intellectual elements of the approach to the improvement. The following formed part of the respondent's approach which, taken element by element, as a process of analysis, can be accepted: it was tolerably clear that the problem would be solved by removing water from the solution, see Dr Davies evidence referred to above; that left solid bicarbonate (whether powder or other dry state); the low solubility of bicarbonate was well known; thus, the answer to the problem was bringing water to the dry bicarbonate on-site; there were two known broad types of method known in chemistry for dissolving a soluble salt in water – placing the salt in a container with water and mixing, by stirring or shaking, and placing the salt in a container and passing water through the bed of that salt; the second such method was known to be more suitable for salts of low solubility; and the principles of percolation or leaching were well known to chemical engineers as part of their fundamental knowledge. 419 At this point the respondent refers to the evidence of Professor Schindhelm at [92] of his first affidavit that at the Priority Date the principles governing the dissolution of soluble salts in water referred to above were well known to a person with a chemical engineering qualification as well as some understanding of the elements of mechanical or fluid engineering. Further, and importantly however, he concluded [92] by saying: [I]t was well known to such persons that a liquid-solid system based on percolation could produce a flow of solution at a known concentration. 420 With this link the respondent submitted that the inventive step was obvious. The intellectual process from the recognition of the need for withdrawal of water to its in situ replacement by percolation, at each step, was said to be obvious. Put another way, Professor Schindhelm said the following at [41] of his first affidavit: In my opinion the change made by Gambro to the existing dialysis systems is neither new nor inventive. The Patent involves the replacement, as a source of the bicarbonate concentrate solution, of a vessel containing liquid bicarbonate with a vessel containing bicarbonate in powder form to which water is added. No other change is made to the existing dialysis systems. 421 There are a number of important difficulties with, or at least qualifications to, accepting this reasoning process as determinative of the question of obviousness. First, the evidence of Professor Schindhelm of the kind in [92] referred to above must be understood against the recognition that he accepted that it was not usual to use percolation to prepare a solution of a specific concentration. Secondly, percolation or leaching was not shown to produce solutions from pure solute (as opposed to extracting solute by leaching) other than sugar syrup. Thirdly, none of the references provided by Professors Schindhelm and Coster refers to production of dialysis fluids by passing water through a vessel. Fourthly, someone (namely, Dr Davies) of eminent qualifications, who fitted the description of a person with chemical engineering training, with an understanding of concepts of mechanical or fluid engineering and with an understanding of the prior art (though given to him for the exercise) did not come to the invention or improvement in the Patent. 422 Overall, weighing all the evidence of Professors Schindhelm and Coster and Dr Davies, I am not prepared to conclude that the invention was obvious. Indeed I do not think that it was. 423 Particular submissions were put in relation to the individual claims in relation to obviousness. 424 It was submitted that if "containing" means "includes" then a "vessel containing a powder concentrate" does not have a limitation requiring that the vessel have no water in it. It was submitted that the claim in claims 1 and 2 was sufficiently wide to incorporate the mixing method used in the 1980s. I cannot agree. The vessel contains powder, not powder and water and water is introduced by the second fluid conducting means. Read in the light of the prior art and the body of the specification, for the reasons I have earlier set out, on-line continuous operation is contemplated by the claims. 425 Submissions were made that there was nothing inventive about passing of water from top to bottom (being no more than leaching), the requirement for a constant concentration (which could be effected by a batch method or use of percolation), the requirement of a particular particle size and the use of a cartridge. These submissions reflected the emphasis of the respondent's case that the explanation of the successful operation of the Patent could be explained by well known principles. That however does not make obvious the conception and implementation of the idea in the manner claimed. 426 I am fortified in my conclusion that the invention is not obvious by a number of facts and circumstances. First, at the conclusion of the cross-examination of Professor Schindhelm the following exchange took place: Mr Catterns: When you were at the centre at the university, what was its correct title? Prof Schindhelm: The Centre for Biomedical Engineering, at that time. Mr Catterns: Your colleagues were working at biomedical engineering solutions to a number of problems in your various fields, weren't you? Prof Schindhelm: Yes. Mr Catterns: And as well as operating at a high level of academic excellence, it was a fairly entrepreneurial centre wasn't it? Prof Schindhelm: Yes. Mr Catterns: It was, amongst other things, aware of the value of patents from the point of view of the centre, and if you could find something patentable? Prof Schindhelm: It would have been, yes. Mr Catterns: I think, was it at the time he was head of the centre that Professor Farrell was Businessman of the Year? Prof Schindhelm: I don't know, my memory is not good. Mr Catterns: But if you or your colleagues came up with something that you thought was patentable, did you patent them or seek advice as to whether something was patentable? Prof Schindhelm: We did. Mr Catterns: And are you yourself named as an inventor on any patents? Prof Schindhelm: Yes. Mr Catterns: Have you got a rough idea how many? Prof Schindhelm: Eight to ten. Mr Catterns: Are there any, broadly speaking, in the field of dialysis? Prof Schindhelm: No. Mr Catterns: Were you aware in 1987 of any problems caused or inconvenience caused by the making of the B solution in nine or ten litre drums by nurses at the point of haemodialysis? Prof Schindhelm: I was aware of the inconvenience and the problems posed by it, yes. Mr Catterns: But it didn't occur to you or your colleagues to come up with a solution of the type that the Gambro patent does? Prof Schindhelm: No. Mr Catterns: Would you agree that it is an elegant solution to that problem? Prof Schindhelm: It is a very nice solution to that problem. Mr Catterns: And it's simple, effective and efficient? Prof Schindhelm: It works, yes. Mr Catterns: But it's simple, effective and efficient, isn't it? Prof Schindhelm: Yes. 427 Mr Archibald submitted that this exchange was limited to the cartridge, which enters the claims at claim 28. I did not understand this evidence at the time, nor do I read it, as so limited. I think this exchange with Professor Schindhelm, together with his ready acceptance of the proposition that it was not usual to prepare a solution of solute of a given concentration by using a percolation process and the evidence of Dr Davies, illuminated the question of whether it could be said that the respondent had proved that there was not even a scintilla of invention in the conception and implementation of the ideas set out at [352] by the claims in the Patent. 428 Secondly, the apparent commercial success and acceptance of the applicants' system conforms with a conclusion that an appreciable practical advance was made. In June 1996, the respondent reported to its parent company that the biBag system was vital to the respondent, since most hospitals would not consider the purchase of machines if an on-line bicarbonate system was not offered. One document, a marketing plan of the respondent in 1996 for Australia, identified as a threat to the respondent's business new technology and innovation such as Bicart (the name of the applicants' on-line cartridge system) which was identified as one of the applicants' strengths in Australia. Whilst one needs to exercise caution in taking too much from the indicia of some commercial success without a complete understanding of the business and the market it trades in, in particular one needs to recognise that such indicia are not to be used as a surrogate for analysis of the evidence of the art and the relevant principles, they are considerations which are not foreign to drawing an overall conclusion as to whether the respondent has proved that there was no inventive step: the 3M case at 298, and Firebelt Pty Ltd v Brambles Australia Ltd at 292-93 [47]-[51]. 429 Thirdly, the respondent has the onus of proof in respect of obviousness. It is the Australian subsidiary of the German parent which designed and designs and manufactured and manufactures, amongst other things, dialysis machines and systems. I was not assisted by any evidence whatsoever of the development of the biBag system. Further, only a handful of documents were discovered by the respondent concerning research and development by the German parent and related bodies corporate in relation to the biBag system. Shortly after 10 May 2002, Tamberlin J made an order (in [2002] FCA 581) of the kind suggested by Lockhart J in Sabre Corp Pty Ltd v Russ Kalvin's Hair Care Co (1993) 46 FCR 428, 432. The order was that the respondent take all reasonable steps to obtain such documents from other companies in the Fresenius Group. No such documents were discovered. A stay was sought. Tamberlin J refused to stay the cross-claim: [2002] FCA 1359; 56 IPR 446. His Honour did, however, conclude that the cursory efforts disclosed by the evidence did not amount to all reasonable attempts to obtain the documents. Whilst I accept that there may well have been significant logistical difficulty in those in Germany identifying and collecting documents concerned with the research and development of the biBag system, the evidence allows me to conclude that there was no disconformity in interest between the respondent and its German parent. If there was evidence that the biBag system was developed in circumstances, which demonstrated facts to assist the assertion of obviousness, I would have expected that it be called. The applicants, similarly, did not lead evidence of the "process of invention" undertaken. But the respondent bore the onus on the question of obviousness. Overall, I do not ascribe significant weight to this factor, except to say that it is a factor to weigh in the balance in giving me comfort in the conclusion that I have otherwise drawn that the Patent was not obvious. Residual Rulings on Evidence 430 During the hearing, after discussion with both senior counsel for the parties, I took the course of admitting some material in affidavits subject to objection. I indicated to the parties that I would rule on these matters on a final basis in my judgment. Both sides indicated that not only did this not cause them any difficulty, but that in the circumstances it was the preferable course. 431 The rulings on evidence made during the course of the trial are contained in exhibit C and exhibit C1, being the rulings on applicants' objections to respondent's affidavits and summary of rulings on respondent's objections to the applicants' evidence, respectively. Exhibit C – Rulings on Applicants' Objections to Respondent's Affidavits First Affidavit of Professor Schindhelm 27 December 2001 432 Whole I will not reject the whole of the affidavit , rather I will deal with relevant particular objections. Para 17 and remainder of affidavit so far as it relates to obviousness The applicants objected by reason of the material before Professor Schindhelm not being part of the common general knowledge. I do not propose to reject the evidence of Professor Schindhelm for this reason. As can be seen by what I have earlier said, I think he is in the correct field of expertise and any particular difficulties with the foundation for his evidence goes to weight. Paras 20-21 I allow the paragraphs. Paras 33-37 I allow the paragraphs. Para 34 I allow the paragraph. Para 40 I reject the paragraph, but allow it, as I did with other paragraphs at the trial, to remain as a submission. The issue is one of the construction of the claims. I do not see the necessity for any particular expertise of the witness in reading the claims in the respects set out in this paragraph. Para 90 I allow the paragraph. Para 91 I allow the paragraph. Para 93 I allow the paragraph. Para 94 I allow the paragraph. Para 95 I have earlier referred to the fact that it was not proved that Remington's was part of the common general knowledge of the relevant worker in the field. To that extent the evidence should perhaps be rejected. However, I have dealt with it on the basis that it is not material of that kind and I will allow it subject to weight and also to form the foundation for understanding my reasons otherwise. Para 96 I allow the paragraph. This evidence is sufficient in my view to support the proposition that someone with the chemical engineering background had as part of his or her common general knowledge the applications of the leaching process referred to in the work. Para 98 I have already commented upon the difficulties of the two paragraphs of [98] of the affidavit. I think the better course is to allow the paragraphs to remain. They have the difficulties to which I have earlier referred. I have taken the view that those matters go to weight. Others may have a different view. Another course would be to reject this evidence. If there were any doubt about the legitimacy of discounting Professor Schindhelm's views because of the effect of the operation of knowledge of Stasz and Mund in this thinking (although obtained after he initially formulated his view) I would reject the two paragraphs. Para 99 I make the same observations. Para 100 I reject this paragraph. Para 101 I allow the paragraph. Professor Schindhelm's second affidavit 16 June 2003 433 Whole I do not propose to reject the whole of the affidavit. Para 9 from the words "and any team" in the third sentence to the end. I allow these parts of the paragraph. Para 12 second last sentence I allow the sentence. Para 14 I reject the paragraph. The question of the skilled addressee or the relevant worker is not assisted by the evidence of Professor Schindhelm in this regard. Para 15, third, fifth, sixth and seventh sentences I reject the third sentence. Professor Schindhelm lacks personal knowledge for this evidence. I allow the fifth sentence and I reject the sixth and seventh sentences on the basis that Professor Schindhelm lacks the personal knowledge to give that evidence. Para 16 second sentence and last sentence I allow both sentences. Para 38 third, fourth and fifth sentences I reject these sentences. They are not based on Professor Schindhelm's personal knowledge. Para 39 I reject this paragraph on the same basis. Paras 41-77 The parties were to identify portions to be rejected and portions to remain as submission only. In the document which was sent to my chambers the relevant schedule for paragraphs 41-47 was not attached. The parties should identify that schedule so that exhibit C can be completed. Para 78 Other than dealing with the sentences already dealt with in exhibit C, I do not propose to reject the balance of paragraph 78. Para 80 I have dealt with part of paragraph 80. I otherwise admit it. Paras 82 and 83 Although Professor Schindhelm had some experience of working with nurses and dialysis technicians as revealed exhibited in his third affidavit, I do not think, in form, that these paragraphs should be allowed. He does not purport to be recalling his experiences. I reject paragraphs 82 and 83. Para 85 second and third sentences For the same reasons I reject these sentences. Para 85 last sentence I reject this sentence. It is an argumentative submission. Para 86 I think this is argumentative submission and should be rejected. Para 87 I allow the paragraph. It sets Remington's in its place. However, I do not think that it amounts to proof that it is in the common general knowledge of someone with chemical engineering expertise who is attempting to improve a dialysis machine. Para 88 This concerns the dissolution of sugar into a syrup which I have already described and dealt with. I will allow it. Para 89 Again I have dealt with this earlier in a manner going to weight. I will allow the paragraph. Para 91 I allow the paragraph. Para 92 I allow the paragraph. The paragraph shows, it seem to me, the difficulty of disclosing the Patent to the witness. The thought processes involved at paragraph 92 flow from the existence of the general principles and are necessarily divorced from a conception of looking forward from the Priority Date without the benefit of the improvement identified in the Patent. Para 94 second sentence I allow the sentence. Para 95 second sentence I reject the sentence. Para 97 last sentence of second paragraph I allow the sentence Professor Coster's First Affidavit 27 December 2001 434 Whole I do not propose to reject the whole of Professor Coster's affidavit. Para 18 I allow the paragraph. Professor Coster's Second affidavit 28 May 2003 435 Whole I refuse to reject the whole of Professor Coster's second affidavit. Para 5 I admit the first, second and third sentences. I reject the balance of paragraph 5 as not shown to be within Professor Coster's personal knowledge or expertise. Para 10 second sentence I reject the sentence as being beyond his expertise and personal knowledge. Affidavit of Lindsay Malcolm Berry 12 November 2001 436 Mr Berry's affidavit was relied upon as material going to the skilled worker in the field as to obviousness. Mr Berry was a dialysis technician, as was Mr West. After a career in the Navy Mr Berry took up being a dialysis technician. His evidence revealed his skill in that field. However, he was not a chemical engineer or scientifically trained. Some of his evidence was the subject of agreement, such as the schematic representation of the type two and type three systems. Mr Berry did not begin to be employed as a dialysis technician until after the Priority Date. Much of his evidence is a description of how the machines work and a description of the alleged infringing systems. 437 I do not understand his evidence as to the operation of the various systems to be in dispute. Mr Berry was not cross-examined. However, to a degree, woven into Mr Berry's evidence could be said to be statements as to the common general knowledge or the state of the art at the time of the Priority Date. I will deal with Mr Berry's evidence in this way that I will allow it to the extent that it is a description of the respondent's system, but reject it to the extent that it can be said either expressly or impliedly that it seeks to give or has the effect of giving evidence as to the common general knowledge or state of the art at the Priority Date or the meaning of the terms in the Patent. Affidavit of Terrence James West 13 November 2001 438 It follows that I would reject the whole of Mr West's evidence in this and later affidavits to the extent that he seeks to interpret the Patent or give evidence as to the relevant worker in the field. 439 I would make the same conclusion as to Ms Yuill's evidence. 440 It should be noted however, that the evidence of Mr West and Ms Yuill was of invaluable assistance in understanding the nature of the procedures undertaken leading up to the Priority Date and the practical day to day aspects of dialysis and related procedures. 441 I will turn to the particular affidavits of both Mr West and Ms Yuill. Affidavit of Terrence James West sworn 13 November 2001 442 All matters in this affidavit were dealt with by the rulings on transcript pages 103 and 104. Affidavit of Terrence James West sworn 17 February 2003 443 Paragraph 2.1 save for the I reject paragraph 2.1. second last sentence which was admitted subject to the limitation referred to at page 125 of the transcript Para 5 Para 2.7 third sentence to end I reject this part of the paragraph. Para 2.8 I reject this part of the paragraph. Para 3.2 first two sentences I reject the sentence. Para 16.5-16.31 and I reject these paragraphs. Mr West does not have the relevant expertise. 16.33-16.3 Para 19.4 second sentence. I reject the sentence. Para 21.1 I allow the paragraph. This is not expert evidence from the skilled worker for the purposes of obviousness, it is direct evidence as to practice that Mr West had experienced as to the use of the percolation process. I limit the effect of the evidence to Mr West's personal knowledge. Para 22.7 to 22.10 I reject these paragraphs as not based on his expertise. Affidavit of Terrence James West sworn 8 July 2003 444 Objection is taken to the affidavit because it was served late. Whilst it was served late the respondent had ample time to develop any aspect of cross-examination to it. More particularly is the difficulty of the kind of evidence Mr West was attempting to give in the affidavit. It is a continuation of the discourse he attempted to have with Professor Schindhelm and Professor Coster. I do not think any of the affidavit is useful. Mr West is not the relevant worker in the field for the improvement of dialysis of machines. His views on Professor Schindhelm's and Professor Coster's affidavit are not helpful and are not relevant, save to the extent that what he says is a statement of fact as to practice at the time before the Priority Date. To this extent I allow paragraphs 2.3, 2.4, 2.7, 2.8, 3.2, 3.5 and 3.6. Affidavit of Elizabeth Jane Yuill 18 February 2003 445 Para 14 I allow the paragraph. This is not inadmissible evidence of someone who is not the relevant worker in the field. It is real evidence of the introduction of the various systems into the market. Ms Yuill was entitled and qualified to deal with all matters otherwise than those previously rejected in paragraph 14.5. Para 15 With the exception of paragraph 15.4 otherwise dealt with at transcript pages 75, 76 and 78, I allow paragraph 15. Para 16 Save for the matters otherwise dealt with at transcript pages 76, 78, 80, 85 and 86, I allow the paragraph. Once again, it is not inadmissible evidence of a worker who is not the skilled worker rather, it is real evidence of events of which Ms Yuill is qualified to give evidence. Conclusions 446 It follows from the above that I would make orders conformable with my conclusions that there has been infringement of the claims as pleaded by the applicants and that I would dismiss the cross-claim. The parties requested that I not make orders so that they may have an opportunity to consider my reasons and formulate what they think are the appropriate orders to reflect what I have said. I am content with that approach. 447 Should the parties take the view that any aspect of the case has not been dealt with I would expect the parties to raise that matter in the context of the formulation of the orders. This is not an invitation for reargument. 448 May I once again, having done so at the trial, thank counsel and solicitors for their skilled and efficient presentation of the case. The presentation at the hearing took place, if I may be permitted to say so, with economy, comprehensiveness and despatch. 449 I would expect the solicitors for the parties to remedy the deficiency in exhibit C concerning [41]-[77] of Professor Schindhelm's second affidavit after contacting my associate. I certify that the preceding four hundred and forty-nine (449) numbered paragraphs are a true copy of the Reasons for Judgment herein of the Honourable Justice Allsop . Associate: Dated: 25 March 2004 Counsel for the Applicant: Mr D K Catterns QC Ms K Howard Solicitor for the Applicant: Blake Dawson Waldron Counsel for the Respondent: Mr A Archibald QC Mr S Burley Solicitor for the Respondent: Allens Arthur Robinson Dates of Hearing: 21, 22, 23, 24, 25, 30 and 31 July and 1 August 2003 Last Submissions filed: 7 August 2003 Date of Judgment: 25 March 2004