May And Baker Ltd & Ors v. Boots Pure Drug Company Ltd [1950] UKHL 1

House of Lords
Case No SESSION 1950-51
Between
May And Baker Ltd & OrsAppellantBoots Pure Drug Company LtdRespondent
Before
Lord SimondsLord NormandLord Morton of HenrytonLord MacDermottLord Reid

LORD MACDERMOTT

My Lords,This appeal, which is brought by May & Baker Ltd., an English Company, and Ciba Ltd., a Swiss Corporation, from the unanimous judgment of the Court of Appeal affirming a judgment of Mr. Justice Jenkins, raises a question of some difficulty.The order of Mr. Justice Jenkins dealt with two matters, (Da petition by the present Respondents, Boots Pure Crug Company Ltd., for the revocation of certain letters patent No. 533,495 which had been granted to the Appellants jointly and (2) a motion by the Appellants that they might be at liberty to amend the specification of those letters patent in the manner which I shall later describe. The learned Judge revoked the letters patent and refused leave to amend. Before the Court of Appeal the only matter in issue was whether the learned Judge had rightly refused leave to amend, the Appellants having conceded that, if that leave was not given, they could not resist revocation. The Court of Appeal (Lord Greene, M.R., and Somervell and Evershed, L.J.J.) were unanimous in holding that the learned Judge had rightly refused leave to amend. It is that matter alone which is now for your Lordships' consideration.Before I refer to the relevant facts I will state the Section of the Patents and Designs Acts, 1907 to 1946, under which leave to amend is sought. By s. 22 of the Act (as I will call it) it is provided that"In any action for infringement of a patent or proceedings before a Court for the revocation of a patent the Court may by order allow the patentee to amend his specification by way of disclaimer, correction or explanation in such manner, and subject to such terms as to costs, advertisement or otherwise, as the Court may think fit: Provided that no amendment shall be so allowed that would make the specification, as amended, claim an invention substantially larger than, or substantially different from, the invention claimed by the specification as it stood before the amendment...".In the application of this section to the matter in hand it must be remembered that the necessary comparison is between the inventions claimed by the unamended and amended specifications respectively, not between the areas of monopoly claimed in the claims of such specifications. It will further be observed that, before leave to amend can be granted, two questions must be decided by the Court, first, whether the proposed amendment is barred by the proviso to the section, and, secondly, if it is not barred, whether it is an amendment which the Court ought in its discretion to allow. It is only upon the first of these questions that I find it necessary to express any final opinion.As I have already said, the letters patent in suit No. 533495 were granted to the Appellants jointly on the 24th May, 1946. The patent had been applied for by Ciba Ltd., as long ago as the 30th January, 1939, the application being made under the International Convention by virtue of Section 91 of the Patents and Designs Act, 1907 to 1938, and being founded upon four applications in Switzerland. The benefit of this application was, pursuant to an agreement made in November, 1944, assigned before grant of the patent to the Appellants jointly.On the 12th September, 1946, the Respondents, having obtained the necessary authority from His Majesty's Attorney-General, presented a petition for revocation of the patent. On the 28th March, 1947, the Appellants applied by motion for leave to amend their specification under the section that I have cited, and on the 15th April, 1947, the motion was ordered to come on for hearing with the trial of the petition. It did so with the result that I have already stated.The patent in suit is concerned with synthetic drugs of the sort known as "sulpha" drugs. I do not propose to weary your Lordships with an exposition of the chemistry involved in the case. The House has the advantage of an explanatory statement of remarkable lucidity by the learned Judge upon which I cannot hope to improve, and I will assume that it is read into this opinion for the purpose of understanding any technical terms that I may use.Substantially the first of the so-called sulpha drugs, of which the therapeutic value was discovered, was sulphanilamide. This was discovered in 1935 and from that time onwards numerous attempts were made by incorporating further chemical groups in the sulphanilamide molecule to improve it by rendering it more deadly to the bacteria it was required to kill but less toxic to human beings. In 1937 the Appellants, working, as it appears, independently, experimented with the inclusion in the sulphanilamide molecule of heterocyclic groups. These researches resulted in the discovery of a drug to which the name of sulpha-pyridinc was given ; a drug which in therapeutic value was markedly superior to sulphanilamide. Experiments in one heterocyclic led to experiment in another and in the result by the inclusion of a thiazole radical in the sulphanilamide molecule the two new drugs, with which this appeal is concerned, were discovered : to them were given the names of sulphathiazole and sulphamethylthiazole. There is no doubt that the discovery of these drugs has been a valuable contribution to the therapeutic art. But it must be said at once that the general character of the methods to be employed in producing derivatives of compounds such as sulphanilamide was known before 1933 and that the production of any particular derivative such as sulphathiazole would not in itself involve invention, although considerable work of a routine character would be necessary in working out the details of a satisfactory process. And it must be emphasised (for this may go to the root of the matter) that it is only by empirical methods that the therapeutic value of any particular drug can be ascertained. I quote a pregnant passage from the evidence of Sir Lionel Whitby, a witness for the Appellants, whose pre-eminence in the science of chemo-therapy is unchallenged. " There is no theory ". he said, and later "the chemo-therapeutic value (if any) of any particular substance " could only be assessed by careful tests of that substance first upon " animals . . . and secondly on human beings."The Appellants Ciba Ltd. having discovered these drugs and, having as I have said, in the course of the year 1938 made certain applications in Switzerland to which I do not think it necessary to refer, on the 30th January. 1939, lodged their British application with complete Specification No. 533.495. On the 31st July. 1939. it was laid open to public inspection ; on the 14th February, 1941, it was accepted and published and on the 23rd April, 1941. the Appellants. May & Baker Ltd.. filed opposition to it. In the meantime May & Baker Ltd. had themselves filed a complete Specification No. 517,272 to which Ciba Ltd. had filed opposition. These cross oppositions were carried a certain distance, but in 1944 the parties came to an agreement, as a result of which the application of May & Baker Ltd. was withdrawn and, as already stated, the patent in suit was granted to the Appellants jointly. I mention in passing that a further opposition had been filed by Ward Blenkinsop Ltd. but this was disposed of by an amendment which is not material to the present appeal.I now come to the original specification. The true construction of it is, I think, the most material factor in this case. It begins (as under Sec. 2 (4) of the Act it must begin) with a title and the title is significant. It is "Manufacture of New Benzenesulphonamido-Derivatives". There is nothing specific about this. The applicants then go on to declare the nature of this invention and in what manner the same is to be performed, to be particularly described and ascertained in and by the following statement".Then follows the so-called "consistory clause" beginning with the words "This invention consists in". As a matter of plain English, my Lords, I find it hard to think of more suitable words with which to preface a statement of the nature of the invention claimed by the specification, and, as that is the very matter in debate, let me set out what the inventor says is his invention. There is no ambiguity about it:This invention consists in a manufacture of new benzene sulphonamido-thiazole derivatives, wherein a benzene sulphonic acid containing as a nuclear substituent in the para-position an amino-group or substituent capable of conversion into an amino-group is converted in the form of a reactive acid derivative (other than a benzene sulphonic acid halide having a free amino-group in para-position) into a benzene sulphonamido-compound containing as a substituent in the sulphonamido-group the radical of a thiazole by a method known to be capable of converting reactive acid derivatives of benzene sulphonic acids into benzene sulphonamides containing a hydrocarbon radical as a substituent in the sulphon-amido-group. The word 'known' is to be understood as designating methods described in the literature.The expression 'substituent capable of conversion into an amino-group' is used herein to denote an acylamino-, nitro-, nitroso-, azo- or hydrazo-group or a halogen atom.The process may consist in causing the nuclear substituted benzene sulphonic acid in the form, for instance, of its halide or ester to react with a thiazole containing an amino-group. Alternatively, the nuclear substituted benzene sulphonic acid may be caused to react in the form of its amide with a thiazole containing a halogen atom.When there is used a benzene sulphonic acid derivative of which the nuclear substituent is capable of conversion into an amino-group, the invention also includes the subsequent treatment of the resulting sulphonamido-derivative to convert into an amino-group the substituent so convertible.The amino-group in the benzene sulphonic acid derivative may be a substituted amino-group, for instance, an alkylamino-, N-acyl-N-alkylamino- or aralkylamino-group; and the benzene sulphonic acid derivative may contain still further substituents, for instance, an alkyl-group.As thiazoles there may be named, for instance, amino-thiazoles and amino-alkylthiazoles."Having thus stated the nature of the invention the inventor proceeds: ' The new para-amino benzene sulphonamido thiazoles find application in " therapeutics. They have chemo-therapeutic activity in streptococci infec-" tions and similar illnesses. The especially favourable activity of the " products will be gathered from the following experimental data." These sentences can mean only one thing, viz., that all the compounds described in the consistory clause have therapeutic value—and, moreover, since the only point in saying anything about therapeutic value is to give subject matter to the invention, it must mean that all such compounds have a greater therapeutic value than (say) sulphanilamide. The specification goes on: " The named compounds were tested as to their remedial effect on mice " infected with highly virulent streptococci and also as to their toxicity. From " the subjoined table it will be seen that the compounds obtainable as " described in Example 1 herein have about 5 times the effectiveness exhibited " by the already known sulphanilic acid amide. Especially to be noted is the " considerably smaller loxicity of the 2-(para-amino-benzenesulphonamido)-" thiazole made as described in Example 1." Then follows a table in which is given the relative effectiveness of the two new drugs and of sulphanilamide. Then two examples are given. They are introduced by the words: " The " following examples illustrate the invention, the parts being by weight." No criticism has been made of these examples which appear to give to a chemist the necessary information to enable him to make the exemplary drugs. This concludes the body of the specification and now I come to the claims which are prefaced by the usual words: " Having now particularly " described and ascertained the nature of our said invention and in what " manner the same is to be performed, we declare that what we claim is : _ ". The claims are of such significance both in what they contain and in what they omit that I must state in full at least the first and the fifth and last of them.The first claim is "1. A manufacture" (an ambiguous term here agreed to mean a process) "of benzene-sulphonamido-thiazole derivatives, wherein a benzene sulphonic acid containing as a nuclear substituent in the para-position an amino-group or a substituent capable of conversion into an amino-group of the kind hereinbefore defined is converted 31 in the form of a reactive acid derivative (other than a benzene sulphoic acid halide having a free amino-group in para-position) into a benzene sulphonamido-compound containing as a substituent in the sulphonamido-group the radical of a thiazole by a method known to be capable of converting reactive acid derivatives of benzene sulphonic acids into benzene sulphonamides containing a hydro-carbon radical as a substituent in the sulphonamido-group."The second third and fourth claims also relate to processes of manufacture but. no more than the first claim, refer specifically to the two compounds sulpha thiazole and sulpha methyl thiazole. The fifth claim is as follows: —5. Benzene-sulphonamido-thiazole-derivatives whenever prepared or produced by the manufacture particularly described and ascertained herein or by any process which is an obvious chemical equivalent thereof."My Lords,I have set out thus in detail the unamended specification, because it is only by the consideration of it as a whole that one can arrive at a just conclusion of the question what was the invention claimed. Having done so I can give no other meaning to the document than to say that the inventor claims that the whole range of benzene sulphonamido derivatives which fall within the consistory clause is his invention, not indeed in the sense that he discovered that they could be made or how to make them, but in the sense that he discovered that, one and all, they had therapeutic value. The title, the consistory clause, the claims themselves, admit of no other meaning. It was urged upon the House that that is not the way a chemist works, and that accordingly the document is to be read as a statement by the inventor that he had by experiment found that two compounds falling within a scientifically ascertainable group had therapeutic value and drawn the inference that all compounds falling within that group had similar value. I am not concerned with the process of reasoning which led to the claim. If it is correctly stated, it is not, as an example of the inductive method, to be commended. What I am concerned with is what the inventor has claimed, and, let his method of reasoning be qualified by whatever epithet you like, he has, as I should have thought beyond all controversy, claimed as his invention the process of manufacture of a vast range of chemical compounds and the chemical substances resulting from that process. It does not, as it appears to me, in any way alter the nature of that invention that he has illustrated it by two examples of specific compounds which fall within the general description. If he had not done so, that would by itself have been good ground for revoking the patent under Sec. 25 (2) (h) and (j) of the Act. I have emphasised what in my view is the invention claimed. Before I turn to the proposed amendment, I will only add that there is not one hint in the document that the exemplary drugs, sulphathiazole and sulphamethylthiazole, were essentially distinguishable from any other members of the vast group within which they fall, or that they had some peculiar characteristic which gave them therapeutic value. No one, I suggest, could fairly read the document without concluding that their therapeutic value was derived from a generic quality: they illustrated the invention just because they had that quality. If there was any lingering doubt upon this point, it must, I think, be dissolved by the fact that no separate claim is made for the manufacture of these two specific drugs or for the drugs themselves or either of them.I come then to the proposed amendment. I willingly approach it from the point of view so often indicated to your Lordships, that generally the purpose of an amendment is to validate a patent whose validity is otherwise open to attack and that that purpose is recognised by the Act. It is however recognised with a proviso.The proposed amendment, which is indicated in red and green ink upon the original specification, is extensive, but it can be slated in a few words. For in effect the amendment in the body of the specification substitutes the two exemplary compounds for the whole range of compounds, so that "the invention consists in a manufacture" of the two compounds, and in the claims cuts out the first four general claims altogether and for the fifth substitutes a specific claim to the two exemplary compounds " produced by the manufacture particularly described and ascertained at page 1, lines 37 to 53, herein " [which had themselves been amended] "or by any process which is an obvious chemical equivalent thereof".The question then is whether the invention claimed by the amended specification is different from, and, if so. substantially different from that claimed by the unamended specification. J do not refer to the words of the proviso "substantially larger than", for it is, I think, clear that the amendment is not in this respect offensive.I share the difficulty, generally felt and often expressed, in determining what exactly is meant by "different" and "substantially different" as used in S. 22 (and in S. 21) of the Act and am glad to think that under the new law that difficulty will not arise again, though another may take its place. I think however that no special connotation can be given to the words in their context, and would adopt the language of Evershed LJ. that "all cases must be judged by the same broad and (as I think) common sense test ". It is perhaps useful in applying such a test to follow the course taken by the same learned Lord Justice and to remember that the area of invention, assuming it to coincide with the monopoly claimed, becomes a "prohibited area which, though in the case of a medicinal drug it is not absolutely barred to competitors, at least offers them little encouragement. Let it be remembered too that within this prohibited area, upon which others may not freely enter, the patentee may be at ease, content with the progress he has made and denying to others the opportunity of which he does not care to avail himself. This is the background against which the test of "difference" is to be examined.Is there then a difference in the inventions claimed in the original and amended specifications? On the one hand a vast range of possible compounds, a fragment no doubt in the whole sphere of organic chemistry, yet so numerous that the number becomes meaningless: within which no one can say what hidden things might be brought to light, what benefits discovered for the relief of humanity. On the other hand two specific drugs. Are these inventions the same or different inventions? My Lords, I hesitate to appeal to common sense, lest others should take a different view of the case. Yet in the consensus of opinion of all the learned Judges who have dealt with this matter I find justification for the view which I most emphatically hold that it is plain common sense to say that the inventions are not the same but different: and I think that, if they are different, the substantial difference could not be denied.My Lords,I am conscious that I have so far ignored a fact which learned Counsel for the appellants put in the forefront of their argument, viz. that the two specific drugs are themselves described by way of illustration or example in the body of the specification. Their argument is thus compendiously stated in Paragraph 17 of their formal case, "that to limit the claims of a specification to the only form of the invention specifically described in the unamended specification, and therein claimed in general terms, cannot be to claim a substantially different invention " not at first sight appear obvious why this should be so. For, if a specific drug falls within the general terms of the invention whose nature is stated in the consistory clause and is for that reason to be regarded as the same invention, it remains the same invention whether or not it is specifically described by way of example or illustration. The sameness or difference of the two inventions cannot be determined by the fact that the patentee has elected to give the one as an example of the other, though I do not doubt that, if he does so, the probability is in favour of their sameness. in this case, if the invention of sulphathiazole is not different from the invention of the vast group of which it is a member, it is not different, and therefore it is the same, irrespectively of whether it is specifically described or not. Yet I do not think that it was seriously contended that, if it was sought to amend the specification by claiming as the invention not sulpha thiazole but some other drug of therapeutic value falling, as sulpha thiazole does, within the general group but not specifically described in the specification, such an amendment would be permissible. I will revert to this later but first mention one other matter.It was sought to link up the contention to which I have referred with the familiar practice of which the latest exposition will be found in the speech of my noble and learned friend Lord Morton of Henryton in the Raleigh Cycle Case 65 R.P.C. at p. 157, where he explains how a patentee, fearing that his earlier claims may be stated too widely and his patent therefore be held invalid, claims protection in his final claim for the " preferred " embodiment" of his invention which he has described in the specification.It is not. I think, now open to question that the practice to which my noble and learned friend referred may be lawfully pursued. Its legality is implicit in the decision of this House in the Raleigh Cycle case which binds your Lordships. But it appears to me to beg the question here to be determined to say that in every case, in which the patentee has stated the nature of his invention in wide and general terms and then given an illustration of it. he can shift his ground and claim that his invention is not the general but the particular. He can do so if, but only if, they are the same inventions. That remains the question to be solved, and it is to be solved by a consideration of the facts of each case.Is then the Court in the consideration of this question to be precluded from enquiring whether the illustration given by the patentee is in fact an illustration of the invention that he has generally described? I can see no reason why this should be so. For, if it were so, to proceed by faulty reasoning to an extravagant and even reckless claim might get more than its just reward. It is in fact irrelevant to the question of the sameness or difference of the two inventions that the patentees have chosen the specific drugs which they now claim to be their invention to illustrate the invention which they formerly claimed. If a drug, which falls within the genus generally described, has a therapeutic value which depends on its unique characteristic, then the invention of it must be different from the invention of the genus. It cannot in this respect, because it is given a name and used as an illustration, be distinguished from its anonymous brethren in the same genus. But then it is said that by definition " invention " includes an alleged invention, and that it follows that the Court must, in comparing the inventions claimed in the old and new specifications respectively, assume the truth of what is alleged. It must proceed on the basis that all members of a certain group of chemical compounds have therapeutic value, and that sulphathiazole, being a member of that group, therefore has therapeutic value: a perfect syllogism, which precludes all further enquiry, and requires the Court to ignore two facts which have been clearly proved or admitted, first, that not all members of the group have therapeutic value ; and, secondly, that the therapeutic value of sulphathiazole depends on special features which are not common to the group. For two reasons I think that the Court in the exercise of its jurisdiction under s. 22 of the Act is not thus stultified. First, the definition of invention is preceded by the words " unless the con-" text otherwise requires ", and, if the introduction of the word " alleged " in this context has the result suggested, then the context assuredly " other-" wise requires ": secondly, this argument gives to the word " alleged " a meaning which I think it cannot bear. In Johnson's Patent 55 R.P.C. at p. 19 the Court of Appeal approved what had been said in Muntz case (39 R.P.C. 335) by the learned Solicitor-General, afterwards Lord Hewart, L.C.J., ""although in the Act of 1907, as indeed, in the Act of 1883, the words 'alleged invention' were employed, it is quite clear, as has been declared by more than one Law Officer, and as one would expect apart from any expression of opinion in any quarter, that the word 'alleged' in this definition goes only to the epithet 'new' and does not make that an invention which is not a manner of new manufacture but which the alleged inventor chooses to describe as an invention". I agree with this and would say, therefore, that in the exercise of its jurisdiction under Sec. 22 the Court, comparing the old and the new inventions claimed, is not debarred from an examination of the facts by the introduction of the word "alleged".Counsel for the Appellants further relied on the passage in the judgment of Maugham J. in /. G. Farbenindustrie A.G.'s Patents 47 R.P.C. 289 at 325, where that learned Judge rejected the idea that amendment should depend merely on the form of drafting adding, "If, as in this case, the claims could originally have been separated up without difficulty, so that the excess matter sought to be disclaimed could readily be treated as included in a separate claim, should not the amendment be allowed under Section 22? On the whole I incline to that view."My Lords,I do not think that the Appellants get any help from this somewhat tentative observation. In the first place, as I have already pointed out, no claim was made for the two specific drugs and no explanation was offered why a patentee, who was by no means inops consilii, did not make it. In the second place it is a sheer begging of the question to say that in this case " the claims could originally have been separated up without difficulty ", if by that is meant that the Comptroller, having the knowledge of this art and of the facts which this case has disclosed, ought to have treated the invention of a group having a general therapeutic value as the same thing as the invention of a specific drug having a particular therapeutic value, and ought accordingly to have granted one patent to cover them both. I am clearly of opinion that he ought to have done no such thing. I do not ignore that the Comptroller, not knowing what was now known, might have granted such a patent, and that in that case there might be the specific as well as the general claim, and, further, that in that case S.32A of the Act might in the event of an infringement action create a position of peculiar difficulty. But it is not a hypothetical difficulty that has to be faced and I decline to test the validity of the Appellants' case by creating it.I conclude then that the proposed amendment will make the invention claimed substantially different from that claimed before amendment. In reaching this conclusion I have pursued my own line of reasoning but in doing so I have gratefully borrowed from the judgments of Jenkins J. and the Master of the Rolls, from no word of which do I see any reason to dissent.Finally, it is right that I should make some observations upon the other authorities that have been cited. I would begin by saying that they are of little assistance, both because every case must be judged by its own facts and because the facts in relation to a chemical invention are of a peculiar character to which other inventions and particularly mechanical inventions afford little analogy. It is a field in which as a rule empirical research industriously pursued will win the prize, and it may well be, as learned counsel for the Appellants was inclined to urge, that the inventive chemist will obtain inadequate protection for his empirical discovery, if he cannot make a general claim and, upon challenge, amend it to a narrower one. That may be so, but it will not justify the Court in applying to a case like the present words used in relation to a wholly different subject matter. For instance counsel relied on the language used by noble Lords in this House in Ralston v. Smith 11 H.L.C. 223 and Seed v. Higgins 8 H.L.C. 550. In the former case Lord Westbury L.C. stated that the object of the Act authorising disclaimers (5 and 6 Will. IV c. 83) was that "when you have in your specification a sufficient and good description of a useful invention, but that description is imperilled or hazarded by something being annexed to it which is capable of being severed leaving the original description, in its integrity, good and sufficient, without the necessity of addition, then you might by the operation of a disclaimer lop off the vicious matter, and leave the original invention as described in the Specification untainted and uninjured by that vicious excess". I should not in the least dissent from this statement as applying also to S.22 of the Act. But the operation which Lord Westbury had in mind is remote indeed from the wholesale abandonment of the invention originally claimed which the amendment here proposed would effect. Equally, where Lord Cranworth, referring to the distinction between Ralston v. Smith and Seed v. Higgins* affirms that "you might disclaim something which leaves untouched a description which is itself perfect", I would not impute to him the thought that the result of this amendment would be to leave untouched a perfect description of the invention as originally claimed.In the judgment of Sir Stafford Cripps, S.G., in Wistoft's Application 48 R.P.C. 461, I find language which more nearly than any other expresses the distinction that I seek to make. " The question," he says, " whether the " amendment of a broad claim to limit it to a particular class of machine " within the ambit of the original claim is a mere cutting out of matter which " may properly be disclaimed or is in effect the introduction of a new idea " or a change of the centre of gravity of the invention, is a question which " must be decided on the facts of each case ". To cut out of the invention the whole of a vast number of compounds save two only, which remain there by virtue of a character peculiarly their own. is to remove the centre of gravity (if the expression may be pardoned) from the centre of the circle to the very edge of the circumference. Some assistance too can be got from the British Thomson-Houston case 36 R.P.C. 251. There, too, it was sought to justify the amendment by saying that it would exclude part of the subject-matter claimed. But. as was pointed out by Sargant J. (whose judgment was affirmed by the Court of Appeal) " the diminution of content was correlative to and directly consequential on a corresponding increase in intent, or in other words, in the description and definition of the invention claimed ". I am aware that that case is distinguishable from the present in that the proposed amendment introduced words of description which were not in the original specification. But the case appears to me to illustrate equally the introduction of new matter or the shifting of the centre of gravity. Either of these things may lead to the invention in the amended specification being substantially different from that in the unamended specification.For the reasons that I have given I am of opinion that the proposed amendment is not permissible under the Act and would dismiss this appeal accordingly. It is unnecessary for me to deal with the issue of "disconformity" which was also raised in the Courts below. I concur in what Jenkins J. said on this matter. I am also relieved from the necessity of considering whether, if the amendment were permissible, the Court ought in the exercise of its discretion to permit it. But I think it right to add that, reluctant as I should be to interfere with the exercise of the learned Judge's discretion, I do not find the same compelling force in this part of a judgment to which I would once more acknowledge my indebtedness.

Lord Normand

My Lords,The Appellants make an application under section 22 of the Patents and Designs Acts 1907 to 1946 to amend their Patent Specification No. 533,495. The material provisions of the section are :
"In any action for infringement of a patent or proceedings before a Court for the revocation of a patent the Court may be order allow the patentee to amend his specification by way of disclaimer, correction or explanation in such manner, and subject to such terms as to costs, advertisements or otherwise, as the Court may think fit: Provided that no amendment shall be so allowed that would make the specification, as amended, claim an invention substantially larger than, or substantially different from, the invention claimed by the specification as it stood before the amendment."
The Court has therefore a discretionary power to grant or refuse the application, but the discretion is fettered by the proviso under which no amendment is competent if the result of making it would be that the amended specification would claim an invention substantially larger than or substantially different from the invention claimed by the unamended specification. There is a question of discretion and there is a question of competency, and it is the question of competency which comes first. But there may be cases in which, after the issue of competency has been decided in favour of the applicant, the same considerations as were relevant to if might still play a legitimate and important part in influencing the Court's exercise of its discretion.In the present case the judgments of the trial judge and of the Court of Appeal have been against the competency of the application. They have held that the invention claimed in the amended specification is substantially different from that claimed in the unamended specification.The construction of the proviso to section 22 does not. I think, cause much difficulty. There are two terms of comparison, the invention claimed in the amended specification and the invention claimed in the unamended. It is agreed that the inventions referred to are not the inventions as they are claimed in the "Claims" at the end of the respective specifications, but the inventions asserted by each specification read and construed as a whole, including the body of the documents as well as the "Claims" at the end. The meaning of the words "substantially larger", or "substantially different" is more controversial. It was argued for the Appellants that the requirement was satisfied if the amended specification did not claim an invention substantially greater "in any direction" than the invention claimed in the unamended specification. This attempt to narrow the meaning of "substantially different" to a difference of "extent", and in particular to exclude a difference of kind, in my opinion failed. I agree with the Master of the Rolls that "the section quite clearly contemplates that the invention claimed by an amendment may be substantially different from that originally claimed notwithstanding that it may be properly described as 'by way of disclaimer'", and with

Lord Justice Evershed's statement:

"The phrase 'substantially different' is common enough in the English language. There is nothing in Sec. 22 to give it a special meaning. It requires no minute analysis, no elaboration by way of metaphor for its explanation."
I may add that for the purposes of the comparison which the Court must make under the proviso it is irrelevant to enquire whether the amendment will or will not have the effect of making an invalid patent valid. That is no doubt the purpose of an amendment, but whether the amendment was necessary and whether it has succeeded are matters indifferent to this question of competency. The terms of the comparison, it must always be remembered, are the alleged inventions.In construing the specifications the ordinary rules for construing documents apply. Extrinsic evidence is admissible to explain the meaning of technical language so that the Court may be enabled to read the document with the same understanding of its terms as that possessed by the persons to whom the specification is addressed. But extrinsic evidence is inadmissible for the purpose of contradicting or modifying the document. It is therefore incompetent to ask a skilled witness how he would construe the specification ; and it is for the same reason incompetent to argue that because an expert would know that a statement or claim asserted by the document, construed according to the natural meaning of its language, is contradicted by scientific knowledge or experience, the language used must be construed in some modified sense. If it is sometimes convenient to say that the specification should be read as it would be read by a qualified addressee, it is as well to remember that that is not a completely accurate statement and that the addressee postulated must be assumed to read it with the will to believe what he finds set down in it.It would be logical to consider next what is the invention claimed by the unamended specification according to its true construction. But as that is the main issue in the appeal, I prefer to postpone consideration of it and to deal first with the other term of the comparison, the invention asserted in the amended specification about which there is substantial agreement. The amended specification claims two new substances, 2-(para-amino-benzene-sulphon-amido)-thiazole and 2-(para-amino-benzene-sulphonamido)-4-methyl-thiazole. These two substances are made by known methods from known materials described in the specification. So far therefore there is no invention, for there is neither utility nor inventive step. These are found in the discovery asserted by the specification that the two substances have especially therapeutic activity in streptococci infections and similar illnesses. "Especially therapeutic" activity means, as the table which follows shows, especially therapeutic as compared with the already known drug, sulphanilic acid amide. The invention is not claimed as anything but an empirical discovery of a particular attribute of each of two separate substances. There is no assertion of a scientific discovery that the therapeutic activity attaches to them by virtue of an ascertained chemical characteristic common to them and to other possible substances similarly compounded. It is as if the inventor were saying "here are two new drugs which may safely be added to the pharmacopoeia, and each of them is more effective in treating streptococci infections than the drug at present in use, but I do not profess to know why." I agree with Jenkins, J. who says that the Appellants make essential to their invention the characteristics peculiar to the two specific bodies."I now turn to the construction of the unamended specification. The consistory clause states that the invention consists in a manufacture of new benzene sulphonamido thiazole derivatives defined in such general terms as to comprise a wide range of compounds described as pa ra-a mi no-ben zene-sulphonamido-thiazole derivatives. The processes of manufacture described correspond in width with the generality of the invention set out in the consistory clause. There follows the same clause as that in the amended specification in which the same therapeutic value is claimed for the whole range of new substances as is claimed for the two specific substances in the amended specification. Here, however, it is necessary to consider the clause in more detail. It states that "the especially favourable activity of the products will be gathered from the following experimental data. The named compounds were tested as to their remedial effect on mice infected with highly virulent streptococci and also as to their toxicity. From the subjoined table it will be seen that the compounds obtainable as described in Example 1 herein have about five times the effectiveness exhibited by the already known sulphanilic acid amide. Especially to be noted is the considerably smaller toxicity of the 2-(para-amino-benzene-sulphonamido)-thiazole made as described in Example 1." That last named substance is the first of the two substances claimed in the amended specification. There follows the table in which that substance and the other specific substance claimed in the amended specification are shown to have been found by experiments on mice to have therapeutic activity superior to that of the known sulphanilic acid amide and also to be less toxic. The specification then continues "the following examples illustrate the invention" and the examples are again the two specific compounds claimed in the amended specification. Claims 1 to 4 cover the various processes of manufacture of the whole range of the substances in which the invention is said to consist. The fifth claim is to the substances themselves with the same wide generality. In the words of Jenkins J. "it is not in dispute that" on the face of them the claims of the specification in its unamended form "extend to all those methods of producing substances, and all substances" produced by those methods, which purely as a matter of chemical definition "fall within their scope, whether the substances in question are, therapeutically or otherwise, valuable or not." But for the present purpose we must look also at the body of the specification and Jenkins J. found as a matter of construction that it contains a representation that all substances produced by the methods and from the materials prescribed are of therapeutic value and have specially favourable activity, comparable to the results obtained with the two specific substances instanced in the experimental data. This construction is not now disputed and it has an important bearing on the meaning of the specification as a whole. The specification treats the two substances as typical examples, not as palmary examples of the invention. As Jenkins J. found, they were mentioned "for the purpose of showing that the invention as claimed would work, and not as in any way qualifying or restricting the invention claimed. None of the features peculiar to the two specific substances were essential to the invention as claimed or essential to them in their character as examples." It is to be noticed that there is no separate claim to the two substances. It was said for the appellants that this was " mere draftsmanship," an error of omission which could be rectified by supposing that such a claim had been made, and that the specification might be construed as if it contained the claim. Specifications like other documents must be construed as they are, not as they might have been. The absence of a claim of this particular kind, which is almost a matter of style where it is appropriate, cannot be dismissed as a negligible inadvertence. The addition of a claim for the two specific substances would involve the recasting of the specification, for the claim would not fit the character of the• invention asserted in it as it stands. That invention is a generic invention in which the utility is a generic property invariably associated with the chemical characteristics of the genus. It is really not possible to read the specification as a compendious manner of claiming a vast number of substances, each of which has been found to have therapeutic virtue, and of claiming among them the two specific substances as especially satisfactory or effective examples. Such a claim if made would be rejected by the least sceptical of qualified addressees as a gross and palpable falsehood. But the appellants put forward a construction which deserves more serious attention. It is put by Evershed L.J. in a few sentences so clear and so fair to the appellants that I would respectfully adopt them. He says:
" The strength of Mr. Drewe's argument rested in this: that his clients, having " applied themselves for therapeutic purposes to that part of the vast field " of benzene sulphonamide derivatives which consisted essentially in the " coupling of the thiazole radical with the sulphonamide radical, had, beyond " question, discovered two such compounds of great therapeutic value. A " patent confined to those two substances alone would (he urged) in the " circumstances have afforded to them wholly insufficient protection. They " had therefore cast their net wide enough to comprehend all substances in " which the essential element of coupling above referred to was present, but " leaving it plain on the face of their specification that they were drawing " a chemical inference from the data they had obtained in the form of the " two specific compounds."
The argument and the construction of the specification implied in it are open to grave objections. They set aside the plain categorical statements of the specification that the invention consists in the manufacture of new benzene sulphonamide thiazole derivatives and that the new para-aminobenzene-sulphonamido-thiazoles have especially favourable therapeutic activity. These general statements are no longer to be accepted as statements of fact and they are to be regarded rather as a scientific hypothesis. It seems to have been forgotten that they were the basis of a patent grant just because they were treated as statements of fact, and that they were put into the specification and followed by commensurate claims for the purpose of obtaining a monopoly in the large field covered by the claims. An equally important objection is that the argument fails to account for the absence of a claim to the two specific substances. But the objection in principle is that this is reading the specification with the eyes of a sceptical expert who does not believe what he reads and who substitutes for what he reads something which he thinks might reasonably be asserted and claimed. Let it be here recalled that the appellants have acquiesced in the finding of Jenkins J. that on a proper construction of the specification there is an assertion that every substance capable of being produced by the described methods from the prescribed materials was of the especially therapeutic value, and that they have obtained from the same learned Judge a finding that they believed what they asserted, that is they committed themselves to this statement as a true generalization from their experimental data. Having so committed themselves they cannot now draw back and say that they are committed only to the truth of their assertions about two specific substances and to an unproved scientific hypothesis.Whether the invention asserted in the amended specification differs substantially from the invention asserted in the unamended specification becomes, after the construction of the two specifications has brought us to the point at which the two terms of the comparison have been ascertained, a question of fact and degree.But it is said that Jenkins J. and not only he but the Court of Appeal also, have misdirected themselves by contrasting the inventive steps required for the inventions instead of the inventions themselves. It is true that in the Courts below the inventive step which is the basis of the discovery that an enormous range of substances having a common chemical characteristic have therapeutic virtue as a generic property was said to be substantially different from the inventive step underlying the discovery that each of two specific substances has therapeutic value. I think myself that the difference between the two inventive steps and the difference between the two inventions are in this case really the same thing. The difference between the two inventions is to my mind obvious. In the one case the inventor is saying that every member of a certain genus is therapeutic. From that it follows that further tests of any substance that can be made within the genus by experiments on mice or on men are superfluous. In the other case he is saying nothing like that, but merely that two new drugs have the therapeutic virtue. When the appellants put their pen through the genus they deleted the whole invention, and when they wrote in the two specific substances they wrote into the specification an invention different in kind from that which they had deleted. The amendment is not a means of reducing too broad an alleged invention to a part of it, or even to a narrow invention of the same kind. Though I think that nothing can in this case be made of a distinction between the invention and the inventive step, there is no valid reason against treating the inventive step as a crucial test of the difference between the two inventions for the purposes of Section 22. No better reason was adduced than that the inventive step need not be disclosed in the specification. But that premise does not lead to the conclusion that when the inventive steps are apparent from the terms of the two specifications they may not be used to test whether the inventions are substantially different. It was further objected that in arriving at their conclusion Jenkins J. and the Court of Appeal had made use of evidence dehors the specifications. I do not think that that proposition was established. But underlying the objection there is a confusion between construing the specifications in order to ascertain what the alleged inventions are, and the comparison of the two inventions one with the other. Once the stage of construction is over extrinsic evidence is admissible, and the Court is indeed bound to have regard to relevant extrinsic evidence in determining the question of fact whether the one invention differs substantially from the other. There may be cases in which the question would depend at least in part on extrinsic evidence, and in the present case the extrinsic evidence has I think been used, particularly in the judgment of the Master of the Rolls, in order to throw into relief the difference between the two inventions disclosed by the specifications themselves. The argument was that this was incompetent because the Comptroller, who still has under section 21 a jurisdiction, which was once his exclusively, to decide whether an amendment would, if allowed, lead to a claim for an invention substantially different from that claimed in the unamended specification, has to exercise this jurisdiction without the advantage of hearing evidence. The logic of this argument limps. No tribunal can use evidence unless it is available, but that is no reason for disregarding relevant evidence when it is available.It was strenuously maintained that the judgment of Jenkins J. was inconsistent with Section 14 (2) of the Acts or would at least cause some embarrassment to the Comptroller in the exercise of the administrative functions committed to him by Section 14 (2). The Comptroller has a delicate and difficult duty to perform under the Acts, and his duty under Section 14 (2) to grant a patent for one invention only has to be reconciled by considerations of common sense and administrative convenience with his discretion under Section 16 (1) to grant a single patent for cognate inventions. But nothing that has been said either by Jenkins J. or by the Court of Appeal should in any way embarrass the Comptroller in the exercise of his functions. The unamended specification as construed by the Courts below does not contain more than one invention; it contains only one generic invention. That is the very basis of the judgments, which therefore imply no criticism of the grant of a patent for the invention. Whether the Comptroller would have granted a patent for the invention claimed in the amended specification I do not know. My opinion is that this specification claims two inventions, and that that is the necessary result of the reasoning of the judgments under appeal. But whether they might have been treated as cognate inventions under Section 16 is not an enquiry hujus loci.Lastly the appellants sought to rely on Section 32A. But the basis on which this section might have been invoked is lacking. There is in the unamended specification no claim for the two specific substances. That is to say that there is no claim of which the Appellants now assert the validity. I have given my reasons for holding that the absence of this claim cannot be treated as mere draftsmanship.A number of cases were cited. But authorities are not of assistance on the two questions on which this appeal turns, the question of the proper construction of a particular document and the question of fact and degree whether there is a substantial difference between the two alleged inventions. None of the cited cases were concerned with specifications for inventions within this particular field of chemo-therapeutics. It is a field which possesses some peculiarities. Two arts must work together in its investigation; there is a large part to be played by the chemist, and yet the invention must be completed by the therapeutist who tests the substances empirically. Without his part there is no proved utility and no subject matter. All applied sciences are empirical, but they are not all empirical in the degree to which this science is, in the present state of knowledge, empirical. The chemist in other fields, as in industry, has made and is making discoveries in which the experimental data do establish the truth of a general scientific proposition. But in this field, where he is trying to discover chemical substances which will destroy certain types of bacteria, this satisfaction is denied to him. Yet his plight is not so helpless as some parts of Mr. Drewe's argument depicted. He can in spite of being unable to make well founded generic claims, obtain an effective protection: why else has he striven with so much skill and persistence and at so great a cost against judgments so powerful and so discouraging to obtain the restricted protection of the amended specification?For these reasons I agree with my noble and learned friend on the Woolsack that the Appeal must be dismissed.

Lord Morton of Henryton

My Lords,I am in agreement with the admirable judgment of Jenkins, J., unanimously upheld by the Court of Appeal, on every point save two, namely: —(1) I think that the amendment put forward by the Appellants would not make their specification No. 533,495, as amended, claim an invention substantially different from the invention claimed by the specification as it stood before the amendment. In other words, the amendmentdoes not offend against the prohibition contained in the proviso tos. 22 of the Patents and Designs Act, 1907, as amended up to the15th April. 1946 (hereafter referred to as "the Act").(2) I think that the specification, as sought to be amended, would not be open to objection on the ground of " disconformity " under the latter part of s. 25 (2) (/) of the Act. It is unnecessary, however, to deal separately with the issue as to disconformity, as counsel for the Respondents said that he could not maintain his argument under this head, if his argument under the first head failed to convince your Lordships' House.Before considering the contents of the specification in suit, in its original and in its amended form, I desire to make some observations in regard to s 22 of the Act. That section has already been read, but I must read the relevant portions of it again at this stage :-
" In any . . . proceedings before a Court for the revocation of a patent the Court may by order allow the patentee to amend his specification by way of disclaimer, correction or explanation, in such manner, and subject to such terms ... as the Court may think tit: provided that no amendment shall be so allowed that would make " the specification, as amended, claim an invention substantially larger " than, or substantially different from, the invention claimed by the " specification as it stood before the amendment…."
In regard to that section I observe as follows :(a) The proviso does not prohibit an amendment which makes the specification, as amended, claim an invention substantially smaller than the invention claimed by the specification as it stood before the amendment. An invention which is substantially smaller than the invention originally claimed may be said, in one sense, to be substantially different from the invention originally claimed, but that cannot be the sense in which the words " substantially different" are used in the proviso to s. 22. Romer, L.J. (as he then was), said in Johnsons Patent, 55 R.P.C. 4 at p. 20, "such an amendment" (i.e., 'by way of disclaimer) "must in many cases make the invention substantially smaller than the invention as originally claimed. But this degree of difference from the invention as originally claimed is impliedly permitted both by reason of the word 'disclaimer' and by reason of the express prohibition of an amendment that will make the invention 'substantially larger'."I respectfully accept and adopt that statement.(b) As I read the section, the comparison to be made is one between two documents, the unamended and the amended specification. For the purpose of ascertaining what are the " inventions claimed " by these two documents respectively, the Court has to consider only these two documents, following the ordinary rules of construction and assisted by expert evidence to explain technical terms. (c)To quote Lord Greene, M.R., in the present case:"It is agreed that the comparison is not to be limited to the claims in the two documents, but must extend to the two specifications as a whole." (d) S. 93 of the Act provides:
"In this Act, unless the context otherwise requires... 'invention' means any manner of new manufacture the subject of letters patent and grant of privilege within Section 6 of the Statute of Monopolies, and includes an alleged invention."
In my view the context does not " otherwise require" in s. 22, and accordingly the Court is comparing inventions or alleged inventions and for this purpose does not consider whether a manner of manufacture is not in truth a " manner of new manufacture ", within the meaning of s. 93.With these matters in mind. I turn to the specification in suit in its un-ainended form. The opening words are of great importance:
"This invention consists in a manufacture of new benzene sulphonamido-thiazole derivatives..."
The patentees go on to explain the process of manufacture by saying that benzene sulphonic acid containing as a nuclear sub-stituent in the para-position an amino group, or substituent capable of conversion into an amino group, is converted in the form of a reactive acid derivative (I can omit the exception mentioned) into a benzene sulphon-amido compound containing as a substituent in the sulphonamido group the radical of a thiazolc. The conversion is to be carried out by certain alternative methods. I need not read these methods in detail. As Jenkins, J., observes, the materials were known and the methods of synthesis were known but (to quote again that learned Judge), " No one had before done or suggested doing that which is described in the specification with the materials therein prescribed, or had produced by any other means any of the new substances claimed by the specification ".The class of new substances described ami claimed in the specification is small indeed compared to the entire field of organic chemistry, but it includes a very large number of substances. There was some evidence to show that the number was not less than 97,000,000, and Jenkins, J., said:
"It can at all events be said without exaggeration that the number runs into thousands"
. The patentees say, at p. 1, line 65 et seq, "The new para-amino-benzene-sulphonamido-thiazoles find application in therapeutics. They have chemotherapeutic activity in streptococci infections and similar illnesses.". I agree with Jenkins, J., that this observation, on its true construction, amounts to a representation that all the substances in question are in fact therapeutically valuable, and I think that such a representation was necessary in order to establish a claim to a patent relating to all these substances. To qtiote again from the judgment of the leamed Judge:
"An invention consisting of the production of new substances from known materials by known methods cannot be held to possess subject-matter merely on the ground that the substances produced are new, for the substances produced may serve no useful purpose, in which case the inventor will have contributed nothing to the common stock of useful knowledge (the methods and materials employed being already known) or of useful materials (the substances produced being, ex hypothesi, useless). Such an invention may, however, be held to possess subject-matter provided the substances produced are not only new but useful, though this is subject to the qualification that the substances produced must be truly new, as opposed to being merely additional members of a known series (such as the homologues) and that their useful qualities must be the inventor's own discovery as opposed to mere verification by him of previous predictions."
The patentees must, I think, be taken as saying, at this point, "We have discovered that every member of this class or range of substances is therapeutically valuable.". They do not say, and they were not bound to say, by what means they discovered this fact, but thev next refer to two members of the class whose therapeutical qualities have been ascertained by experiment. They say "the especially favourable activity of the products will be gathered from the following experimental data". They then go on to describe two drugs, viz.. 2-(para-amino-benzenesulphonamido)-thiazole and 2-(para-amino-benzenesulphonamidoM-methyl-thiazole. They say that these two drugs were tested on mice as to their remedial effect and toxicity, and a table is given showing that these two drugs are much more effective, and much less toxic, than the already known sulphanilamide. The patentees then go on to give two " examples ", telling the public, with full details, exactly how the two drugs already mentioned ought to be made.Pausing here, it seems to me that the patentees are here complying with the statutory requirement that they must disclose the " best method of "performance of the invention" known to them at the time when the specification was left at the Patent Office. They are saying "the best method of" performing our invention is to make the two drugs, specifically described, "in the manner set out in the two examples". These two drugs are now known as sulphathiazole and sulphamethylthiazole. There is no doubt that the discovery of these two drugs was an important invention for the benefit of mankind, and. in my view, to use a convenient phrase which has often been used in the Courts, these two drugs are the "preferred embodiment" of the invention described in the specification. Jenkins, J., found that these two "are undeniably useful drugs, sulphathiazole outstandingly so".Next come the claims. Claim 1 claims the process of manufacture already set out in the consistory clause with which the specification begins. Claims 2, 3 and 4 claim certain alternative processes also described in the body of the specification and Claim 5 claims the broad general class of substances "benzene-subphonamido-thiazole derivatives whenever prepared or produced by the manufacture particularly described and ascertained herein or by any process which is an obvious chemical equivalent thereof".My Lords,I cannot understand why the patentees did not add a sixth claim for the two drugs already specifically described, sulphathiazole and sulphamethylthiazole "whenever prepared and produced by the manufacture particularly described and ascertained herein or by any process which is an obvious chemical equivalent thereof". I shall return to this subject later, merely observing at the moment that no such claim appears in the unamended specification, and it must be construed as it stands. I think Mr. Drewe was right in saying that the alleged invention claimed thereby is an invention of improved therapeutics consisting in the manufacture of any para-amino-benzene-sulphonamido-thiazole derivative and. in particular.as the best method of performance of that invention, the two drugs specifically mentioned. As to the scope of the claims, I accept entirely the view expressed by Jenkins, J., as follows: -
"I therefore construe the unamended complete specification as claiming the described methods whenever applied to the production of any of the substances which purely as a matter of chemical definition fall within the scope of the claims, and, furthermore, as claiming all those substances, whenever produced by the described methods, whether the substances in question are therapeutically valuable or not, but with a representation or suggestion in the body of the specification to the effect that all the substances in question are in fact therapeutically valuable."
I now turn to a consideration of the invention claimed by the amended specification. It can be very simply described. It is the manufacture of the two drugs, sulphathiazole and sulphamethylthiazole, and the only claim in the amended specification is for these two drugs, whenever prepared or produced by the manufacture particularly described or ascertained at page 1, lines 37-53, of the amended specification or by any process which is an obvious chemical equivalent thereof.It is not. I think, disputed that the proposed amendment is one by way of disclaimer, and your Lordships have to determine whether the latter of the two inventions which I have just described is or is not "substantially different" from the former. Certainly it is substantially smaller, and the protection claimed is strictly limited. The reason for the disclaimer is not in doubt.By their original specification, the patentees had represented that every member of the class of substances therein described was therapeutically valuable. Jenkins. J.. felt bound to assume (rightly in my view) in the absence of proof to the contrary, of which, he says. "there was not a vestige", that the patentees "believed that the suggestion or representation in question was warranted as a generalisation from their experimental data in this difficult field". That representation the patentees found it impossible to support, and Somervell, L.J. put the matter in words which I gratefully adopt:
"On such experiments as have been done, two or three compounds have been found to have little or no therapeutic value, which has led to the abandonment of the claim. There are two compounds covered by the original claim, known as succinylsulphathiazole and phthalylsulphathiazole, of undoubted value and in use. The probability appears to be that a large though uncertain number of the vast number of possible compounds covered would be found to have sufficient therapeutic value to justify the original claim."
On the 28th March, 1947, the Appellants launched their Notice of Motion for leave to amend the specification and on the 29th July, 1947. their solicitors wrote to the Respondents' solicitors "they" (the Appellants' "are prepared to and do hereby admit that the specification in its unamended form includes within its scope substances which, it is now believed, would be found, after clinical experience, to have less useful application in therapeutics than the two substances particularly mentioned in the specification..."My Lords,the fact that the invention claimed by the amended specification is substantially smaller than that claimed by the unamended specification admittedly does not of itself render the two inventions "substantially " different", within the meaning of section 22 (see my observation (a) on that section). Is there any other ground upon which the two inventions can be held to be substantially different? In my view there is no such ground. The amendment sought in the present case is to my mind just the type of amendment by way of disclaimer which is contemplated and permitted by section 22. The inventors found that the scope of their invention was not so wide as they had supposed. They described the manufacture of a wide class of new substances, and asserted that every member thereof was therapeutically valuable; they claimed protection for the whole of that class and set out. as the preferred embodiment of their invention, two substances which undoubtedly had the therapeutical value originally claimed for the whole class. Finding that they could not properly maintain their wider claim, because they could not show that every member of the wide class was therapeutically valuable, they desired to disclaim everything except the two specific substances, which undoubtedly were therapeutically valuable. It seems to me that in so doing the Appellants are not claiming a different invention, but are claiming something which is a part of the wide invention originally claimed. Not only is it a part of that wide invention, two substances out of millions, but it is, as Mr. Drewe puts it, the pith and centre of that wide invention, that which was specifically put forward in the original specification as the preferred embodiment of the invention.It was suggested in the course of the argument that these two substances could not be an embodiment of the wide class claimed by the unamended specification ; if the wide class had had the therapeutical value claimed for it, the two substances might be said to be examples of that class, but as the claim for the wide class had proved to be ill-founded, the two substances were not examples of anything; they were merely two substances each of which had been found by experiment to have individual qualities which were therapeutically valuable. My Lords, this suggestion surely overlooks the point that in section 22 the word "invention" includes an alleged invention. For the purpose of ascertaining whether the inventions claimed in the amended and unamended specifications respectively are different, it is necessary to consider the alleged invention claimed in the latter document, on the footing that the statements in that document are true. If the documents are looked at in this light, it becomes apparent, to my mind, that the two substances are two examples of a large class of therapeutically valuable substances, and that the Appellants are merely disclaiming all other members of the class and coming down upon these two substances.I have already commented upon the absence, in the original specification, of any claim for the two drugs specifically described, and have suggested the terms of such a claim, which might have been added as Claim 6. It may be helpful to consider, at this stage,(a) whether the insertion of such a claim would have rendered necessary any amendment in the body of the specification,(b) whether the Comptroller could properly have granted a patent on a specification so framed, and (r) whether the absence of any such claim should have any adverse effect upon the present application for leave to amend. As to (a), the insertion of such a claim would not, I think, have rendered necessary any amendment in the body of the specification, nor would it have affected the construction of any part of the specification. It would merely have been a narrower claim, on the same lines as Claim 5. Both would be "substance" claims, but whereas Claim 5 covers a very wide class. Claim 6 would be limited to.two members of that class, already specifically described. In order to answer question (b), I turn to s. 14 (2) of the Act. which is as follows:-
" (2) Every patent may be in the prescribed form and shall be granted for one invention only, but the specification may contain more than one Claim ; and it shall not be competent for any person in an action or other proceeding to take any objection to a patent on the ground that it has been granted for more than one invention."
It is thus the duty of the Comptroller not to grant a patent if the specification covers more than one invention, but it is contemplated that the specification may contain several claims, and it would seem that the Legislature must have contemplated a series of claims for the protection of one and the same invention, differing in the width of the protection claimed. It has in fact been the practice of applicants for many years, as your Lordships well know, to insert such a series of claims. The first claim is usually a claim for the alleged invention in its widest form and each succeeding claim is usually somewhat narrower than its immediate predecessor. The filial claim is usually a claim for the preferred embodiment of the invention, and the reported cases contain many examples of specifications so drafted. If the original specification in the present case had contained a sixth claim in the form already described, I do not think that the Comptroller would ever have thought that Claim 1 and Claim 6 claimed two different inventions. I think he would have concluded, and rightly concluded, that a claim for an invention of wide scope, followed by a claim for the preferred embodiment of that invention, cannot offend against the provision that " every patent shall be granted for one invention only "If the Court of Appeal were right in the present case, I think that the Comptroller's duty under section 14 (2) would be rendered much more difficult. Whenever he found a series of claims, of the kind already described, he would have to consider "the inventive step" in regard to the alleged invention covered by each claim, and be it observed, the applicant for a patent is not bound to state his inventive step in his specification.As to question (c), in my view the absence of any separate claim to the two drugs in the original specification should not adversely affect the present application for leave to amend, and I think that this view is supported by the relevant authorities. Maugham, J. (as he then was), in the case of I.G. Farbenindmtrie A.G.'s Patents, 47 R.P.C. 289. at p. 325, put the point as follows : —
"It is true that in such a case" (that is where a separate claim was included) "the patentee by separating his claims has enabled the Court separately to consider the inventions claimed to be the basis of the patent. But ought such a matter to depend merely on the form of drafting? If, as in this case, the claims could originally have been separated up without difficulty so that the excess matter sought to be disclaimed could readily be treated as included in a separate claim, should not the amendment be allowed under Sec. 22? On the whole I incline to that view, and I should prima facie be disposed to allow this amendment of Patent C."
I think that these words, which I gratefully adopt, apply exactly to the present case. The view thus expressed by Maugham, J., is. to my mind, entirely in accordance with the views expressed by your Lordships' House in Seed v. Higgins. 8 H.L.C. 550. and Ralston v. Smith. 11 H.L.C. 223. As these two cases not only assist in the consideration of my question (c) but also, in my view, lend strong support generally to the contentions of the Appellants, I must refer to them at some length. In Seed's case the Appellant had been granted a patent on the 14th July, 1846, for the invention of certain improvements in machinery for roving cotton. At that time the insertion of claims in a specification was not obligatory, and the same observation applies to Ralston s case. Seed's specification contained the following passage :-"My improvements in machinery or apparatus for preparing, slubbing, and roving cotton, and other fibrous substances, apply solely to that part of such machinery called the flyer, which is employed, in connection with the spindle, for the purpose of winding the sliver or roving upon the bobbin. My invention consists in the application of the principle of centrifugal force to the flyers employed in the abovementioned machinery, for the purpose of producing the required elasticity of pressure upon the bobbin, by causing the small spur or lever, which conducts the sliver of cotton or other fibrous material on the bobbin, to press or bear against the same simply by the action of such force, instead of being effected by springs or such other mechanical pressure. 45 By the application of this invention the bobbins of rovings will not only be made hard, but equally compressed throughout, as the pressure upon the same will be found to decrease slightly as the diameter of the bobbin increases, and thus equalise the formation thereof, instead of having the outer or finished diameter made harder than the interior, which has hitherto been the case.".The specification went on to describe the apparatus, and said that the upper end of the hollow flyer leg
" has a small weight, h, attached thereto. As the flyer, c c, revolves at a high velocity, the weight, h, at the upper end of the wire will be thrown from the centre, and cause the spur or lever, e, at the lower end of the wire to bear or press against the bobbin, b b, the pressure slightly decreasing as the increasing diameter of the bobbins causes the weight, h, to approach the centre of rotation."

A drawing was attached to this description. The specification concluded thus:-

" The above apparatus represents one particular and practicable mode of applying my invention; but I would here remark, thai I do not intend to confine myself to this particular method ; but I claim as my invention the application of the law or principle of centrifugal force to the particular or special purpose above set forth, that is, to flyers used, &c., as before described."
Seed afterwards put in a disclaimer under 5 & 6 Will. 4. c. 83 and 15 & 16 Viet. c. 83 which, so far as material, was in the following terms :-
" Whereas I have been advised that the claim of my invention, contained in the said specification, may be construed in such a manner as to be more extensive than I intended, and by reason thereof I am desirous of making and extending the disclaimer hereinafter expressed."
It then proceeded :
" I disclaim all application of the law or principle of centrifugal force as being part of my said invention, or as being comprised in my claim of invention contained in the said specification, except only the application of centrifugal force by means of a weight acting upon a presser. so as to cause it to press against a bobbin, as described in the said specification ; and I declare that the above-written disclaimer is not intended to extend the exclusive right granted by the said letters patent, and shall not extend the said right in any way whatever."
It was specifically pleaded by the Respondent Higgins that the invention as altered by disclaimer was another and a different invention from that for which the patent was granted. Your Lordships' House rejected this plea and held that the disclaimer was good. Lord Cranworth observed at page 563,
" I think, reading the specification in a fair spirit, we must understand the patentee to have said, that he claimed as his invention the application of centrifugal force to the flyers in the mode elaborately ex- plained in his diagrams. But then he did not confine himself to that mode; he claimed, farther, the application of the principle of centrifugal force to flyers used in machinery for preparing and roving cotton, in what- ever way it might be applied. The effect of the disclaimer was to strike out of the specification this latter general claim, leaving only the claim for the particular mode of application specially described. I think it would be unreasonable and hypercritical to say that on a specification so framed the patentee had not claimed as his invention, or as part of his invention, what he had described. And when, therefore, by the dis-claimer the general claim is abandoned, the particular claim remains good."
It is, I think, important to observe that although Lord Cranworth refers to "the particular claim" the patentee had originally made only the general claim, and by his disclaimer he sought protection only for the "particular mode of application" which he had described, but had not claimed in terms, in the original specification. In this respect the facts in Seed's case bear a strong resemblance to the facts in the present case. Lord Wensleydale said at pp. 564-5 :-
"Upon the first question, which is. whether, after the disclaimer entered pursuant to the statute 5 & 6 Will. 4., c. 83, the patent was good for the particular machine described in the specification. I certainly have doubted. I have had a doubt whether the judgment of the Court below was right on this point, and that doubt is not altogether removed. I do not think this is the sort of case to which the statute was meant to apply. The patent is for every sort of application of the law or principle of centrifugal force to flyers used in machinery, or apparatus for slubbing and roving cotton, &c.. and not for a particular machine or form of doing this, anj the disclaimer is founded on a false suggestion (for false it certainly was) that the patentee's claim might be construed to be more extensive than he intended. That appears to me to be quite a fiction. It is now converted into a patent for a particular machine. But my doubt is by no means such as to induce me to dissent from the united opinions of the Judges of the Court of Queen's Bench, and the opinions of the majority of the Judges of the Court of Error, and, therefore, I agree that the judgment must be affirmed on the point reserved by Lord Campbell on the trial."
I think that the reasons which caused Lord Wensleydale to doubt, if one omits his reference to a false suggestion, were not unlike some of the reasons given by Jenkins, J., and the Court of Appeal in the present case; yet these reasons did not prevail in your Lordships' House. Lord Chelmsford said, at pp. 568-9:
"... it appears to me, that the Plaintiff first claims the particular method described, and afterwards every other application of centrifugal force to the purpose set forth. Then, when he disclaims all application of the law or principle of centrifugal force, except only the application of centrifugal force as described in the specification, he does not abandon the whole of his invention, and leave himself nothing but an illustration of it; but he gives up all that is general, and limits himself to the particular method, which was a substantial and independent claim, to which the general claim had previously been superadded. In this view the disclaimer certainly does not extend the right, nor can it be said to describe a different invention."
Again, I would point out that Seed had not in terms claimed "the particular method described". Later, in approaching the question of infringement. Lord Chelmsford referred to the disclaimer as "having thus narrowed the claim and having fixed it to the precise and particular machine described". That is, I think, a fair description of the disclaimer in the present case, if one substitutes "drugs" for "machine".My Lords,I do not, of course, suggest that the facts in Seed's case were identical with the facts in the present case; but I do suggest that if the reasoning of Jenkins, J., and the Court of Appeal in the present case were correct. Seed's case would have been decided against the patentee.In Ralston v. Smith, 11 H.L.C. 223, this House decided against the patentee, but, in my view, the reasons given for the decision greatly assist the Appellants in the present case. The Lord Chancellor (Lord Westbury), referring to the Act 3 & 4 Will. 4. c. 83, said at p. 243:-
" The object of the Act authorising disclaimers was plainly this, that when you have in your specification a sufficient and good description of a useful invention, but that description is imperilled or hazarded ' by something being annexed to it which is capable of being severed, leaving the original description, in its integrity, good and sufficient without the necessity of addition, then you might by the operation of a disclaimer lop off the vicious matter, and leave the original invention as described in the specification untainted and uninjured by that vicious excess. But it never was intended that you should convert a bad specification in the sense of its not containing no (this must be a misprint for any) description of any useful invention at all, into a good specification by adding words that would convert what has been properly called in the Court below, 'a barren and unprofitable generality', into a specific and definite and practical description. It is quite clear that if that could be done, you would have an opportunity of introducing into a bad patent, which contained no useful invention whatever, some discovery that might be developed by farther experiment, and which was altogether unknown at the time of the original specification, and not at all included in the descrip-tion contained in it."
My Lords,it seems to me that in the present case the Appellants, by their disclaimer are carrying out what Lord Westbury describes as " the " object of the Act", in the first sentence of the passage just quoted, and that Lord Westbury's observations on the Act of 1835 apply equally to section 22 of the present Act.

Lord Cranworth, in Ralston's case at p. 252-3 said: -

"... It is quite clear that the object of a disclaimer cannot be 'to create any new right not included in the original specification. It "cannot be (as it is called) to extend the specification. What the plaintiff here has done is this: He has filed a specification, which I may say is in this sort of algebraical form :
'My specification' consists of A, B, C, D, and all the letters of the alphabet and any 'combination of all the letters of the alphabet'
. But it turns out that nothing will really meet his case but the combination of F and Z together. Now, no doubt, when he had said 'I claim a combination' of all the letters of the alphabet,' a combination of F and Z would be included; but it would be trifling with the knowledge of mankind to say that that sort of specification would communicate anything. It is true that by trying and puzzling over all possible combinations you might have found out the particular combination upon which alone the plaintiff could have relied; but that is not what the words would properly mean, and not what any authority warrants you in taking as their proper meaning. The distinction was very clearly pointed out in the case of Seed v. Higgins before this House, that you may disclaim something which leaves untouched a description which is in itself perfect; but that where you have an imperfect description, you cannot say because it is (according to the language of one of the cases) a mere impractical generality, * I exclude everything except 'one single case, which though involved in it could not by any' reasonable investigation have been discovered by an ordinary person.' "I suggest that in the present case the Appellants are merely seeking to disclaim something which leaves untouched a description which is itself perfect.Before the Court of Appeal the Appellants relied upon the principles laid down in Ralston v. Smith, but did not actually refer to Seed v. Higgins on which the Appellants now rely as confirming and illustrating the decision in Ralston v. Smith.In each of these cases the original claim was a broad one for apparatus having certain general features and the patentee, by disclaimer, sought to limit the claim to the use of apparatus of a single specific form. The Appellants submit, rightly in my view, that the substantial distinction between the cases is as follows. In Ralston v. Smith the particular form of the apparatus to which the disclaimer confined the monopoly was nowhere described in the original specification, the first description of an essential feature of it being contained in the disclaimer; this disclaimer was held bad in law. In Seed v. Higgins the particular form of the apparatus to which the disclaimer confined the monopoly was that described in detail in the original specification "as one particular and practical mode of applying my invention". This disclaimer was held good.When these two cases were decided by your Lordships" House, the Statute permitting amendment did not expressly provide that an amendment by disclaimer should not " make the specification, as amended, claim an indention substantially different from the invention claimed by the specifica-" tion as it stood before amendment ". In my view, however, the reasons given by your Lordships' House in Ralston v. Smith, together with the plea in Seed v. Higgins and its consideration by your Lordships' House, show that an amendment which claimed a different invention was regarded as excluded from the power of amendment conferred by the statute. I think it is fairly said by the Appellants that the present section 22, which in substance appeared first in the Patents Designs and Trade Marks Act of 1883, embodied and to some extent liberalised the law before that date. So far as I am aware, there has been, since the Act of 1883, no case in which the meaning of the section has been considered by your Lordships' House.My Lords,a consideration of the principles laid down in Ralston's case, as illustrated by Seed's case, confirms me in my view that the Appellants are right in the present case.I would add that the question whether two inventions are "substantially different" is one of fact and degree; and a consideration of the Act as a whole leads me to the view that the Courts should not be astute to find a "substantial difference" within the proviso to section 22, where, as here, the patentees have, in fact, made a real invention, beneficial to mankind, have described that invention (namely, the two specific drugs) with the utmost particularity in their original specification, thereby giving to the public the consideration which the Act demands for the monopoly which they seek, and are seeking protection for that invention only, disclaiming everything else which they originally claimed.I regret that the conclusion which I have reached is in conflict with the decisions in the Courts below and with the view held by some of your Lordships. Jenkins, J., described the question as one of considerable difficulty. His first reason for thinking that the proposed amendment could not be allowed was stated as follows :-
"(1) The extent of the disclaimer (without pressing unduly the Petitioners' contrast between 97,000,000 bodies and 2) is so great as in my view to involve a substantial difference in the invention claimed. A claim for described methods of producing from stated classes of materials a range of products running at all events into thousands, coupled with a claim to all those substances whenever produced by those methods, seems to me to comprise an invention fundamentally and substantially different from the invention involved in a claim simply to two specific bodies whenever produced by the described methods, even though those two specific bodies were in fact included in the thousands comprised in the original invention."
I agree with the learned Judge's description of the inventions claimed by the unamended and the amended specifications respectively, but with all respect to him I cannot see that the reduction in the claim from a large class of substances, whenever produced by certain methods, to two specific members of that class, whenever produced by the described methods, amounts to claiming a substantially different invention, within the proviso to section 22. I have already suggested that this is just the type of disclaimer which is permitted by section 22, one which makes the invention claimed substantially smaller, but not "substantially different" in any other sense. I think that the answers which I would give to the other reasons stated by Jenkins, J., sufficiently appear from the views which I have already expressed as to the construction and effect of the unamended and the amended specifications respectively. In the Court of Appeal the Master of the Rolls compared the "inventive step" necessary to give subject-matter to the inventions claimed by the unamended and the amended specifications respectively, and I think that the same comparison was the foundation of the judgment of Evershed, L.J. (as he then was). With all respect to the late and the present Master of the Rolls, I think that section 22 contemplates a comparison, not of inventive steps, but of the two " manners of manufacture ", each being new or alleged to be new, for which protection is claimed in the unamendcd and the amended specifications respectively. It is this comparison which I have endeavoured to carry out. Somervell, L.J., approached the problem in a manner which I entirely accept, and I would adopt, without qualification, the opening passage in his judgment down to and including his statement of the question as follows:-
"Is there a substantial difference between claiming as the invention the therapeutic value of a vast range of benzene sulphonamide thiazole derivatives and two particular derivatives?"
The answer to this question, says the learned Lord Justice, "must be to a large extent a matter of first impression". He answered it adversely to the present Appellants, and his conclusion was based on the very wide nature of the original claim and on the absence of an alternative claim for "the specific substances". I think I have already made clear why I cannot accept either of these grounds as sufficient for a decision adverse to the Appellants.Several cases were cited in argument, in which the Courts have had to consider whether a particular amendment did or did not offend against the proviso to section 22. I have read and re-read those cases. No one of them is a decision of your Lordships' House, and no one of them is a case in which a patentee is seeking to limit his claim to the "preferred embodiment" specifically and clearly described in his original specification. In these circumstances I do not think it would be right to detain your Lordships with an analysis of any of these cases. I need only say that I find nothing in any of them which is in conflict with the argument addressed to your Lordships by counsel for the Appellants.For these reasons I am satisfied that the amendment which the Appellants seek to make is an amendment by way of disclaimer, and that it is in no way prohibited by the proviso to section 22.My Lords,in view of the concession made, very rightly in my view, by Mr. Heald. it is not necessary to discuss the question of disconformity. If the majority of the House had agreed with my views as to "substantial difference", it would have been necessary for me to deal in detail with the question whether the House should exercise the discretion arising under section 22 by allowing the Appellants to amend their specification, and, if so, what terms should be imposed upon them "as to costs, advertisements or otherwise". As the majority of your Lordships' House think, contrary to my own opinion, that the appeal should be dismissed on the ground that the proposed amendments offend against the proviso to section 22, it is unnecessary for me to express a concluded view on any of these questions.

Lord MacDermott

My Lords,The Appellants have undoubtedly invented two new substances of great therapeutic value and the amendment they now seek is designed to confine the grant they have already obtained to those substances alone. The power of the Court to amend does not, however, rest on this consideration any more than it does on the outstanding merit which must attach to the discovery of these beneficent drugs. It depends on the proviso to section 22 of the Act (as it stood before amendment in 1949) and the comparison thereby required between the inventions claimed respectively by what may conveniently be referred to as the amended and original specifications. If the result of this comparison is that the invention claimed by the amended specification is "substantially larger than" or "substantially different from" that claimed by the original specification, then, by the terms of the proviso. the amendment cannot be allowed.It was rightly conceded that the comparison must extend to the documents as a whole and is not to be limited to the scope of the monopolies claimed therein ; and it was agreed that on the facts of the case the relevant test lay in the words "substantially different from". But it was not agreed that a comparison of the inventions claimed required an examination of the underlying inventive steps; and the extent to which evidence outside the original and amended specifications might be regarded for the purposes of the comparison was also in dispute.These two points of divergence stand at the threshold of the investigation and, though I do not think they present any serious difficulty in the circumstances of the present case, it will be convenient to consider them before passing to the nature of the inventions claimed. The Appellants submitted that in section 22 the word "invention" had the meaning ascribed to it by section 93, the definition section, and therefore meant, not the inventive step, but the "manner of new manufacture" referred to therein. I would agree that there is nothing to oust this definition. But the matter is not one of definition; it is whether the nature of the inventive step in each case is a relevant consideration in comparing one "manner of new manufacture" with the other. I have no doubt that it is. It now marks an essential element in the patentable invention and no true comparison can be made if, though ascertainable, it is left out of account. This point leads to the second. How far can evidence of relevant matters, such as this, which lies outside the original and amended specifications, be regarded for the purposes of the proviso to section 22? Now that proviso undoubtedly requires a comparison of these documents and the nature of the enquiry, as I understand it, is such that they must be taken as they stand. On this issue of competence the accuracy of their representations is not in question, and validity or invalidity is not a test. If that is right it follows that evidence adduced to contradict the documents or to give them a meaning different from that to be obtained by applying the appropriate rules of construction ought not to be admitted. This does not mean, however, that the task of comparison is necessarily at an end when the original and amended specifications have been read and compared. That is an obvious first step, but the comparison is between the inventions claimed, and the specifications may be in proper form and sufficient for their purpose without containing all that goes to reveal the true nature of the inventions or the extent of the difference, if any, between them. The specifications may indeed, omit much that is material from this point of view. For example, the nature of the inventive step need not appear and may only be ascertainable when the information afforded by the specification is amplified by a knowledge of the prior art. Or, again, the specification may give no certain indication of the magnitude or range of the invention which may have to be determined by other evidence, just as in the present instance the number of derivatives, the subject of the grant, was explored in evidence in an effort to reach some conclusion on a matter concerning which the original specification was silent and the chemists on either side could not agree. I therefore think that evidence of this sort—that is to say, extrinsic evidence which lets the documents stand as they are but serves to show the real character of the inventions or how much they differ—should not (if otherwise admissible) be left out of account in applying the proviso to section 22. In my opinion this view is in strict accord with the terms of the proviso, for the comparison thereunder is between the inventions as claimed, and not as described by the documents. To hold differently would be to make the comparison an artificial process and the jurisdiction of the Court unduly dependent on the manner of drafting.The nature and extent of the invention claimed by the amended specification is readily ascertainable when this document is read in the light of a knowledge of the art. It is the manufacture of two new compounds of therapeutic value - sulphathiazole and sulphamethylthiazole. The problem was to find some substance at once less toxic and more effectual against certain infections than sulphanilamide. Each of the new compounds provided a solution. They were produced by known methods from known materials and the inventive step lay in the discovery of their virtue as drugs. This achievement was not the result of applying any known principle or law of nature. It was entirely empirical. No doubt the inventors used skill and experience of a high order in selecting a profitable line of research. But they had no means of knowing that success had crowned their efforts until the new products had been tested by experiment. There is conjecture but no certain knowledge as to how these drugs arrest infection. The chemistry of the human body still holds many mysteries and all the organic chemist can do in this sphere is to explore in what he thinks a promising direction and then subject his results to rigorous trials in order to find if his hopes have been well founded. That such was the state of affairs at all material times is, I think, beyond question on the evidence. Tomorrow it may be different, for the bounds of knowledge are ever widening. But for the purposes of this appeal the invention claimed by the amended specification can only be regarded as empirical in character and dependent upon the proved worth of the specific substances described by the inventors.Before proceeding to consider the original specification and the nature of the invention it claims it will be appropriate to mention two matters which, while this particular art remains in an empirical state, appear to me to be necessary consequences of that characteristic. In the first place an invention in this chemotherapeutic field must be in respect of a substance which has actually been produced. There cannot be an empirical discovery in respect of a bare formula. And secondly, the discovery of each new compound having a therapeutic value is a separate invention. If the inventor is bound to say –
" I have made a new substance which I find has therapeutic value, but I cannot be certain that any other substance, no matter how similar its molecular structure, will have such a value until I make and test it"
then, as it seems to me, the inventive step he has taken must attach to the single substance he has made and to it alone. And if he has made and proved several such substances the position must, I think, remain the same for, while the art retains its empirical nature, the worth of each new substance is a new discovery. But when the inventor can say that his inventive step is such that each of the various new products which manifest it must have therapeutic value, and that although some of them have never been made, then, as I see the matter, the state of the art will have changed. It will have lost its empirical nature, at least to some extent, and the chemist will have found some law or principle by which he may predicate therapeutic effect in advance.While I think these considerations must be kept in mind I do not wish to be taken as saying that the second necessarily confronts the Appellants with an insuperable obstacle in claiming by amendment in respect of two ascertained and tested substances. It is true that section 14 (2) of the Act provides that -"Every patent …. shall be granted for one invention only. ..." But if, as I think, these substances are separate inventions it may nevertheless be the case that, having regard to their close chemical affinity and the disclosed methods of manufacture, there would be good ground for considering them cognate inventions or modifications, one of the other, capable of being regarded as constituting a single invention under section 16 of the Act. I express no concluded view as to that or as to the conditions necessary to enable that section to be utilised ; but I will assume for the purposes of this opinion that the amended specification relates to cognate inventions which may be considered as one so far as the question of competence is concerned.I come now to the original specification. What is the nature of the invention it claims? The answer must turn on what that essential ingredient, the inventive step, really is. Is it the empirical discovery that each and all of the new benzene sulphonamidothiazole derivatives obtainable by the processes described are of the therapeutic value alleged? If that is the true view it would, as it were, make the inventive step a multitudinous edition of that behind the amended specification. This would carry the Appellants a considerable distance on their way, though even then, the point that the disclaimer sought sheds such a vast field that the difference it creates is more than merely quantitative would still have to be met.In my opinion, however, this view is untenable for several reasons. I am prepared to assume that a long series of different substances may be described as a class and sufficiently identified as members of the class so described. But even so, the original specification does not, as it seems to me. speak in a manner apt to indicate the kind of inventive step under discussion. Its language is. to my mind, better suited to support the alternative view to which I shall presently refer. Apart from that it is. I think, quite impossible to regard as the inventive step (or inventive steps) the empirical discovery of the therapeutic value of all the derivatives claimed if only for the reason that most of these derivatives have never been made, and have therefore never been put to the test of experiment. This is not in dispute and it is a circumstance which cannot well be ignored. The position might be different had the specification alleged the manufacture and trial of all these substances. But it makes no attempt to do so and is content to state that "The especially favourable activity of the products will be gathered from the following experimental data" and there is then set forth the results of tests with the two named compounds. I do not think any competent chemist would need to be told, after reading the original specification, that the experimental process had fallen far short of covering the entire range of derivatives. He would know that from the passage referred to and the impracticable nature of the task which would be prodigious on any reckoning of the total number of possible derivatives. And when he knew that he would also, I think, conclude that, if the promise of the specification were true, the inventors had found something which made the full laborious routine of trial and error no longer necessary. Another difficulty in the way of accepting this view of the inventive step arises from what I have already said as to the empirical discovery of each new substance's therapeutic value being a separate invention. If that is right the view under consideration would make the original specification embrace not one invention but a myriad of inventions which by reason of their numerical uncertainty—no one seems to know how many feasible derivatives there are - could hardly obtain the benefit of section 16. This would be in the teeth of section 14 (2) and a construction avoiding that result is to be preferred.The rejection of this view of the inventive step for the reasons stated leaves, in my opinion, no tenable alternative save that which commended itself to Jenkins J. and the Court of Appeal and which may be stated as being that the inventive step consisted in the discovery of a scientific truth to the effect that if certain defined classes of materials are combined according to certain processes the whole range of resulting products will have therapeutic value. The more I reflect on the matter the more I am convinced that this is the right view. Once the other view has been discarded, it seems to me but a summary of what the original specification says at greater length when it declares that " This invention consists in a manufacture of new benzene sulphonamidothiazole derivatives", describes the materials and processes for their production in terms which define the class or range, and roundly endows the whole genus with therapeutic qualities of a high order. It may also be observed in its favour that this view does not involve a plurality of inventions and is entirely compatible with the fact that relatively few of the possible derivatives have been made.The question, then, is whether the inventions claimed by the amended and original specifications, and based on what I have held to be the true inventive steps, are substantially different. That they are different admits, in my opinion, of no real doubt once the inventive steps have been ascertained and contrasted. But is the difference substantial? The Appellants contended that all that required assessment in this connection was a difference in quality and not in size. "Substantially larger than". it was pointed out constituted a distinct test, and so an amendment would not, it was said, be claiming an invention substantially different merely because it was substantially smaller. Up to a point there is force in that argument. Quantity and quality cannot, however, be entirely disassociated and I think Jenkins J. was entitled, on this issue, to take into account, as he did, the extent of the disclaimer which, on any reading of the evidence, was of such magnitude that it might reasonably be considered as marking more than a difference in size. Another contention advanced by the Appellants and which in one aspect is akin to that just considered may be mentioned conveniently here, though I do not find it easy to classify. It was said that if the original specification had included a claim limited to the two named drugs the amendment now sought would necessarily have been within the power of the Court to grant under section 22 for, as it was put, one could always "amend down" so as to shed all but a narrow claim to the preferred embodiment. If the views I have already expressed as to the nature of the inventive steps underlying the amended and original specifications are well founded this argument, in my opinion, really begs the question and can lead nowhere. The process of amending down to which reference is made does not, as I understand it, involve any change in the nature of the inventive step which remains intact and available to support the narrow claim. But that is not the position here, for the amendment sought is based on a different inventive step, and the issue of competence arises directly and must be settled according to the terms of section 22.My Lords,whether the difference between the inventions was substantial is so much a question of fact and degree that, unless convinced that the learned Judge was clearly wrong, I would be reluctant to disturb his conclusion on the matter, and that all the more because, if I may say so, his judgment reveals a masterly grasp of the facts and circumstances that go to mark and measure the difference. I have, however, no doubt on this question. I agree with Jenkins J and the Court of Appeal that the difference between the inventions is substantial. I do not rest that view on any of the numerous authorities cited which I have not found sufficiently akin to be helpful. I rest it simply on an examination of the true nature of each invention, as I see it, and a comparison of the conclusions reached. To my mind the difference revealed is so wide and fundamental that it cannot rank as other than substantial.On this ground alone the appeal must fail and it is therefore unnecessary to explore the other issues.

Lord Reid

My Lords,The Appellants seek to amend their Specification No. 533.495. The proviso to sec. 22 of the Patents and Designs Act, 1907, as it stood prior to amendment by the Patents and Designs Act, 1949, First Schedule, provided that no amendment shall be allowed which would make the Specification as amended claim an invention substantially larger than or substantially different from the invention claimed by the Specification as it stood before the amendment. It is not relevant to consider in this case the new form of the proviso enacted by the 1949 Act and it is not suggested that the amendment proposed would make the specification claim an invention larger than that claimed by the unamended Specification. The question in this case is whether the proposed amendment would make the Appellants' Specification claim an invention substantially different from the invention claimed by the unamended Specification. I think that this is a very difficult question, but the difficulty does not arise from any complexity of the chemistry involved. The difficulty is in the application of the words used in the section and in particular in the ascertainment of the precise meaning of the " invention claimed by the Specification ". Whatever be the precise meaning of the word invention, a matter to which I shall have to return, I think that the invention claimed by the Specification must be found by construing the Specification as a whole. This document was addressed to persons skilled in the arts to which it refers - chemistry and therapeutics- and it is therefore necessary in construing it to have in mind such relevant facts as evidence shows would have been known at the relevant time to persons skilled in those arts. I think that it was accepted that the relevant time was some time in the latter part of 1938.The chemistry involved in the case was so fully and lucidly explained by Jenkins, J. (as he then was) that I need only briefly state what appear to me to be the salient facts. In 1933 it was discovered that prontosil red was effective to kill streptococci. This is a compound in which a somewhat complex group is attached to a benzene sulphonarnide group. In 1935 it was discovered that a less complex substance para-amino benzene sulphonaniide had a similar effect. But this substance was not very satisfactory therapeutically: if a sufficient dose was given to kill the bacilli this might be harmful to the patient and much research was devoted to finding a derivative of this substance which did not have this disadvantage. Para-amino benzene sulphonamide is a compound in which one hydrogen atom of benzene, C 6 H 6 , is replaced or "substituted" by an amino-group. NH, and the hydrogen atom at the opposite side of the ring of six carbon atoms (in the para position) is substituted by a sulphonamido group, SO 2 NH 2 . The complete structure is therefore NH 2 < "> SO 2 NH 2 or NH 2 C 8 H 4 SO 2 NH 2 . As NH 2 C 9 H 4 is aniline the name sulphanilamide was coined as an alternative for the full name of para-amino benzene sulphonamide. The structural formula shows that the compound contains 8 hydrogen atoms in four different positions 2 in the amino-group. 2 at the end of the benzene ring next to that group. 2 at the end of that ring next the sulphonamido-group and 2 in the amido-group. Derivative compounds can be formed by replacing any of these hydrogen atoms by one of a great many possible groups and a different result will be got according to the position of the hydrogen atom substituted. As two or more hydrogen atoms can be substituted at the same time it is obvious that the number of possible variations is almost infinite, and the number of these which could be made by known methods was very large indeed. The next step which I need mention was the discovery of the value of sulpha-pyridine, a compound in which one of the hydrogen atoms in the amido-group of sulphanilamide is substituted by a pyridine ring. Pyridine, C 5 H 5 N, can be described as a benzene ring in which one carbon and its attendant hydogen are replaced by a nitrogen atom: it is one of several thousand known heterocyclic compounds, compounds containing a ring structure in which one or more of the atoms in the ring is not a carbon atom.I now return to the original Specification 533,495. Shortly after the therapeutic value of sulpha-pyridine became known the Appellants, May & Baker, and Ciba. independently prepared sulpha-thiazole or one of its simplest derivatives and discovered their therapeutic value. Thiazole is a heterocyclic compound with five atoms in a ring, sulphur carbon nitrogen carbon carbon in that order, each carbon having a hydrogen attached to it and sulpha-thiazole is a compound of the sulphanilanlide and thiazole groups

S

__ / \

with the structure NH 2 <__> SO 2 NH-C CH

N—CH

In 1938 Ciba filed certain Swiss applications and May & Baker filed certain British applications. Ciba made application in the United Kingdom on 30th January, 1939 and ultimately the parties agreed that the benefit of this application should be assigned to the Appellants jointly. May & Baker dropping their application. The patent in suit was granted to the Appellants jointly on 24th May, 1946, the Specification being that to which I have referred.This Specification declares that the invention consists in a manufacture of new benzene sulphonamido-thiazole derivatives by known methods. To make such substances would not have been a patentable invention unless some valuable use had been found for them, and the Specification states this use as follows :" The new para-aminobenzene-sulphonamido-thiazoles find application in therapeutics. They have chemotherapeutic activity in streptococci infections and similar illnesses. The especially favourable activity of the products will be gathered from the following experimental data ".The Specification gives details of how to make two examples of the new substances and sets out the results of testing these substances on infected mice and also the results of making similar tests with plain sulphanilamide which contained no thiazole group. Those results showed a marked superiority of the new substances. The Specification ends with five claims: the first four claim the manufacture of the new substances by various methods and the fifth claims the substances whenever produced by the methods described or by any process which is an obvious chemical equivalent thereto.I have referred to the multitude of derivatives which could be obtained from sulphanilamide. The thiazole derivatives form only a very small proportion of those derivatives but nevertheless the possible thiazole derivatives run into many millions. Not only can the hydrogen atoms of the amino-group and of the benzene ring be substituted but the thiazole-group can be attached in three different ways and then each of the two hydrogen atoms in the thiazole-group can be substituted and two or more substitutions can occur in the same product. I do not think that there is any other important part of the evidence which it is necessary to have in mind in proceeding to construe the Specification. On a fair construction, neither benevolent nor strict, I think that what the Specification means is that the inventor asserts that he has made and tested in the manner stated the two substances which he particularly names, that these are therapeutically superior to sulphanilamide to the degree which his tests show, that any other of the very numerous substances which fall within his description can also be made by the methods which he describes, and that when made and tested it will be found to be therapeutically useful. There was no reason for him to state why it would be useful and he did not do so, nor did he state just how useful it would be, but he did assert that it would be useful. He was bound to give the best examples which he knew; he may have known of others which were rather less useful than those which he set out and I do not think that the Specification asserts that all these substances would be found to be as useful as the two which are mentioned. But a new substance would not be useful at all unless it was better in some way than the original sulphanilamide, and I think that what the inventor asserted, and was bound to assert to justify his claim, was that whichever of the new substances was made and tested it would be found superior in some respect to sulphanilamide.It now appears that this assertion was not justified and the Appellants do not contend that all or even substantially all the substances claimed are useful. Only a very few of them have ever been made and the Appellants' original wide claim must have been based, if it had any basis at all, on an inference that, because certain of the simpler sulpha-thiazole derivatives had been found to possess valuable therapeutic qualities, therefore all others of that class of derivatives would be found to have similar properties. But it appears that in this field such an inference cannot properly be made. The reason why these substances kill certain bacilli is not accurately known and it is not possible to infer from the behaviour of one substance that another which is chemically its nextdoor neighbour will have similar therapeutic qualities. In the present state of knowledge one must proceed not by inference but by trial and error. The most that can be said is that having found valuable therapeutic qualities in one member of a class one would expect to find other members of the class to have those qualities to a similar, greater or less extent and one would hope to find some that were better than the original, but no one can predict the behaviour therapeutically of any particular member of the class. I think that this is the substance of the evidence of Professor Hey, one of the Respondents' witnesses, whose evidence was fully accepted by Jenkins, J. The evidence of the Appellants' witness. Sir Lionel Whitby, is even less favourable to them. I think that the inventor might have been justified in asserting that within the class claimed further valuable substances would be found but that is very different from the assertion which was made. Accordingly the Appellants have recognised from an early stage that they could only save their patent by amendment.The amendment proposed is certainly drastic. The Appellants seek to disclaim everything except the two substances particularly described in the original Specification. The Specification as amended would declare that the invention consists in a manufacture of these two substances by known methods, and that they have chemotherapeutic activity in streptococci infections and similar illnesses; it would give details of how to make them and set out the results of tests as before and it would end with only one claim - a claim to these two substances whenever produced by the methods described or by any process which is an obvious chemical equivalent thereto. I think that on a fair construction what the amended specification would mean is that the inventor still asserts that he has made and tested these two substances and that they are therapeutically valuable, but he makes no assertion about any other substance.What then are the inventions claimed by the original and amended specifications within the meaning of section 22 of the Act? Invention is a word which is used many times in the Act. It is defined in section 9.1 as meaning, unless the context otherwise requires, any manner of new manufacture the subject of letters patent and grant of privilege within section six of the Statute of Monopolies and as including an alleged invention. I think that when section 22 refers to an invention claimed it includes an alleged invention: an invention claimed by a specification is the same whether or not it turns out later on investigation that it was no true invention. The invention claimed must I think be discoverable at the beginning from a construction of the specification in light of such explanation of technicalities as is necessary. But I do not think that it can be discovered by looking at any particular words in the specification. Section 14 (2) of the Act provides that every patent shall be granted for one invention only, but the specification may contain more than one claim. Section 16 refers to inventions which are cognate or modifications one of the other and permits the Comptroller, if he is of opinion that the whole of such inventions are such as to constitute a single invention, to accept one complete specification in respect of the whole. Sections 7 and 8 speak of an invention claimed having been already claimed or described wholly or in part. So an invention is not necessarily something which is indivisible: it may have more than one part or aspect: where there are more than one claim it cannot be found defined in any of them. Is the case different where there is only one claim in a specification? Must a definition of the invention then be sought in that claim and nowhere else? I do not see why this should be so. The normal rule is that a document must be construed as a whole. Moreover I think there must be cases where, although the inventor has in fact only made one claim, the material set out in the rest of the specification is such that without adding anything or making any new selection a second or narrower claim could also properly have been included. In such a case I do not think that merely putting in the form of a separate claim something already clearly indicated in the body of the specification as a part of the invention claimed could make the specification claim an invention different from that claimed if there were no separate claim.So regarding the word invention I think that the invention claimed by the Appellants' original specification can be shortly but not inaccurately said to be the invention of the very large number of allegedly useful substances which are comprised within the class or description of para amino benzene sulphonamido thiazoles and their derivatives. The claims also include certain other substances used in the preparation of these substances, but I do not think that this is of much importance. If the proposed amendment is otherwise competent I do not think that this complication would make any substantial difference. Coming to the proposed amendment, if it were allowed the invention claimed would be the invention of the two named therapeutically useful substances. Is this substantially different within the meaning of section 22 of the Act from the invention originally claimed? I think that it is established by authority that one invention must be held to differ from another if. in order to define or explain the second invention, it is necessary to have recourse to something which is not in the original specification or which, though referred to, is not set out as forming part of or essentially connected with the invention claimed. In Wistoft's Patent, 48 R.P.C. 461. the invention related to machines actuated by putting a coin in a slot, and its object was to reject coins which did not have a milled edge. In the original specification a talon-like finger was referred to, but there was nothing to show that any particular value was attached to it and its use was optional. An amendment sought to make it an essential part of the invention. It was held that this would make the specification claim a different invention. In Walsh v. Baker, 47 R.P.C. 458, the invention originally claimed was a lamp and reflector. Hooks for the suspension of the lamp were described but not as part of the invention. An amendment sought to make the hooks an essential part of the invention. Again it was held that this would make the specification claim a different invention. The British Thomson-Houston Co.'s Patent, 36 R.P.C. 251, was a complicated case but I think that the gist of it for the present purpose can be shortly stated. The claim was for "The method of working tungsten which consists in subjecting the metal in a coherent form to the action of heat while it is being operated on or manipulated". It was sought to insert by amendment, "We desire it to be understood that by the expressions 'coherent form' and 'coherent metal' in the claims we exclude any forms of tungsten other than those agglomerated from tungsten powder and rendered very dense and strong by a heat treatment very near the melting point.". Warrington, L.J., said, "The proposed amendment is carefully drawn so as to be in form by way of disclaimer. In my opinion, however, the real effect of it is to import into the specification for the first time the element of selection by rendering essential to the invention claimed that which in the original specification was only one of several means by which the coherent product might be obtained."I.G. Farbenindustrie A.G.'s Patents, 47 R.P.C. 289, was a case of a selection patent where somewhat different considerations apply. If the essence of a patent is a selection or principle of selection of specially useful products from a known field, a substantially different selection must be a substantially different invention. In this case the patentee sought to narrow his claim by introducing a new limitation into the selection set out in the original specification and this was not allowed. There are two older cases to which I should also refer as they were decided by this House, but the section of the Act dealing with amendment was then in different form. In Seed v. Higgins, 8 H.L.C. 550, the specification contained a detailed description of an apparatus for winding cotton on a bobbin and continued, "The above apparatus represents one particular and practicable mode of applying my invention; but I would here remark, that I do not intend to confine myself to this particular method; but I claim as my invention the application of the law or principle of centrifugal force to the particular or special purpose above set forth..." The patentee sought to disclaim everything "except only the application of centrifugal force hy means of a weight acting upon a presser. so as to cause it to press against a bobbin, as described in the said specification " and this was allowed. In Ralston v. Smith, 11 H.L.C. 223, the claim was for a machine with two rollers which would at the same time perform two operations on woven fabrics, one being to impress a pattern on it. It was found that this would not work unless the pattern was of a particular kind and the patentee sought to amend by disclaiming the use of all other patterns. This was not allowed: Lord Westbury said, "The object of the Act authorising disclaimers was plainly this, that when you have in your specification a sufficient and good description of a useful invention, but that description is imperilled or hazarded by something being annexed to it which is capable of being severed, leaving the original description, in its integrity, good and sufficient, without the necessity of addition, then you might by the operation of a disclaimer lop off the vicious matter, and leave the original invention as described in the specification untainted and uninjured by that vicious excess. But it never was intended that you should convert a bad specification, in the sense of its not containing any description of any useful invention at all into a good specification by adding words that would convert what has been properly called in the Court below, 'a barren and unprofitable generality,' into a specific and definite practical description" I think that these authorities sufficiently establish the principle to be followed and I know of no authority which conflicts with them. In this case no new matter is sought to be introduced by the Appellants' proposed amendment. Does it seek to make something an essential part of the invention which was not so before? I do not think so. The two substances were I think a part and an essential part of the invention originally claimed. They were members of the group or class claimed and were the only members particularly referred to. I do not see how it can be said that they were not an essential part of that invention. Does the amendment involve any new element of selection? Again I do not think so. The purpose of an amendment of this character is to discard those parts of the invention originally claimed which are bad and retain what is good. If the parts sought to be retained are distinguished in the original specification by forming the subject of a separate claim there is generally no difficulty. The difficulty arises when the patentee wishes to pick out from a claim which is too wide parts or instances which can be the subject of a valid patent. In one sense it might be said that you can never disclaim down to something which was not the subject of a separate claim in the original specification without making a new selection. But it is clear from authority that there are cases where it is permissible to disclaim down to a claim which was not set out in the original specification : indeed even in the case of a selection patent there is high authority for this. In I.G. Farbenindustrie A.G.'s Patents, Maugham, J. (as he then was), said:
"It is true that in such a case" (where there are separate claims in the original specification) "the Patentee by separating his claims has enabled the Court separately to consider the inventions claimed to be the basis of the patent. But ought such a matter to depend merely on the form of drafting? If, as in this case, the claims could originally have been separated up without difficulty so that the excess matter sought to be disclaimed could readily be treated as included in a separate claim, should not the amendment be allowed under Sec. 22? On the whole I incline to that view, and I should prima facie be disposed to allow this amendment."
If a patentee seeks to pick out from a claim something which is not distinguishable in his original specification from the rest of the subject matter of the claim then I think that he is seeking to introduce a new selection and to that extent a different invention. But here I think that the two substances were distinguished in the original specification by the inclusion in it of full particulars of their manufacture and therapeutic effect. In Ralston v. Smith Lord Cranworth said, "The distinction was very clearly pointed out in the case of Seed v. Higgins before this House, that you may disclaim something which leaves untouched a description which is in itself perfect; but that where you have an imperfect description, you cannot say because it is (according to the language of one of the cases) a mere impracticable generality, 'I exclude everything except one single case, which though involved in it, could not by any reasonable investigation have been discovered by an ordinary person.'" I think that the Appellants' amendment would leave untouched a description of the two named substances which is in itself perfect.There is a good reason why a patentee should not be allowed to introduce a new selection by amendment: the new selection may be based on knowledge which he has only recently acquired, and if it were allowed he would be able to claim something which he had not invented when he got his patent. But that cannot apply here. The Appellants published in the original Specification everything that was involved in or was necessary to justify the claim which they now seek to introduce. No doubt the scope of the original claim is very wide and the scope of the new claim is very narrow, but I do not think that that is a good reason for holding that they are claims to different inventions if I am right in my view that the new claim is a claim to a part of the invention originally claimed.In reaching this conclusion I have not laid stress on either the nature of the discoveries which must be supposed to underlie the inventions claimed or the inventive steps involved and I think that my reaching a conclusion different from that reached by the learned Judges in the Courts below is largely due to the importance which they have attributed to these matters. I do not think that in the case of a specification containing more than one claim it can be of primary importance to consider the inventive steps involved. It has I believe for long been the practice of the Comptroller to allow in appropriate cases the inclusion in one specification of wide general claims together with narrow particular claims and this practice appears to be warranted by the Act. Such claims may well involve substantially different inventive steps but nevertheless these different inventive steps must be held all to relate to the same invention, though no doubt to different parts or aspects of it. One claim may involve one inventive step but I do not think that it necessarily follows that, where the original specification only contains one claim, the nature of the invention claimed must be fully disclosed by considering what is the inventive step involved in that claim: the invention claimed must be discovered from a consideration of the whole specification. In the present case the original Specification appears to me to show that there must have been two stages in the inventor's progress: first the manufacture and testing of the two substances sulpha-thiazole and sulpha-methyl-thiazole (and possibly some others) and then an erroneous inference from the results so obtained. It may well be that the inventive step involved in the claim in the original Specification is substantially different from the inventive step which would have been involved if the inventor had chosen to claim the two substances only. But I do not see why that prevents the invention of these substances from being a part of the wider invention originally claimed. For much the same reasons I doubt whether much emphasis should be laid on the nature of the discoveries involved. An invention is something over and above a discovery and I doubt whether it can be said that two claims based on different discoveries cannot be parts of the same invention. Moreover the validity of an invention does not depend on the validity of the supposed discovery which led the inventor to his invention. The invention may work and be useful although the supposed discovery is erroneous. No doubt there is a wide difference between the theoretical discovery of a general scientific truth about a class of substances and an empirical discovery of the value of certain members of the class but I do not think that it follows that the invention of those members of the class cannot be held to be a part of the invention of the whole class.For the reasons which I have stated I am of opinion that the proposed amendment is competent. But it does not necessarily follow from that that this Appeal must succeed. If the majority of your Lordships had been of opinion that the amendment is competent it would have been necessary to go on to consider whether as a matter of discretion it should be allowed. That question is neither simple nor easy to answer and in the circumstances I think that it would be inadvisable to express any opinion on it. I shall therefore say no more than that I am unable to agree that the Appeal should be dismissed on the grounds which your Lordships have stated.

Die Jovis, 9° Febroarii 1950

Upon Report from the Appellate Committee, to whom was referred the Cause May and Baker Limited and others against Boots Pure Drug Company Limited, that the Committee had heard Counsel, as well on Monday the 28th, Tuesday the 29th and Wednesday the 30th days of November last, as on Monday the 5th, Tuesday the 6th, Wednesday the 7th, Thursday the 8th, Monday the 12th, Tuesday the 13th, Wednesday the 14th and Thursday the 15th, days of December last, upon the Petition and Appeal of May and Baker Limited, having their registered office at Dagenham, in the County of Essex, and Ciba Limited, a body incorporated according to the laws of Switzerland and having their seat at Basle, Switzerland, praying, That the matter of the Order set forth in the Schedule thereto, namely, an Order of His Majesty's Court of Appeal of the 10th of December 1948, might be reviewed before His Majesty the King, in His Court of Parliament, and that the said Order might be reversed, varied or altered, or that the Petitioners might have such other relief in the premises as to His Majesty the King, in His Court of Parliament, might seem meet; as also upon the printed case of Boots Pure Drug Company Limited, lodged in answer to the said Appeal; and due consideration had this day of what was offered on either side in this Cause:It is Ordered and Adjudged, in the name of the House of Lords, by the Lords of Appeal sitting in the House of Lords during the Dissolution of Parliament, by virtue of a Writing by His Majesty the King under His Sign Manual, dated the 3d day of February 1950 pursuant to the provisions of the Appellate Jurisdiction Act, 1876, That the said Order of His Majesty's Court of Appeal, of the 10th day of December, 1948. complained of in the said Appeal, be, and the same is hereby, Affirmed, and that the said Petition and Appeal be, and the same is hereby, dismissed this House: And it is further Ordered, That the Appellants do pay, or cause to be paid, to the said Respondents the Costs incurred by them in respect of the said Appeal, the amount thereof to be certified by the Clerk of the Parliaments.