C. D. 28, 30. Henderson, 50 App. D. C. 191; 269 Fed. 707; 284 O. G. 182; 1921 C. D. 133. Knudsen, 51 App. D.C. 224; 277 Fed. 623; 296 O. G. 839; 1922 C. D. 76. Power, 52 App. D. C. 72; 281 Fed. 432; 302 O. G. 780; 1922 C. D. 132. Tanner, 305 O. G. 420; 1922 C. D. 39. One exception to this rule does not affect the question now under consideration. Joliffe v. Waldo v. Vermeer, 234 O. G. 671; 1917 C. D. 15. Fanslow v. Whitney, 266 O. G. 742; 1919 C. D. 93. Nash v. Reeder v. Ryan, 208 O. G. 589; 1920 C. D. 72. On the contrary when an applicant presents a claim which is patentably different in scope, he cannot be rejected as barred by the judgment tho he may be barred by latches, or he may lose the interference under the rule of res judicata. One partial exception occurs when the disclosure is held to be inoperative. This fact of inoperativeness is res judicata, and a claim of any scope, dependent upon the same disclosure, may be rejected upon the adjudication of inoperativeness. Kidder, 229 O. G. 269; 1916 C. D. 37, reversing by necessary implication ex parte Mark, 117 O. G. 2636; 1905 C. D. 322.

Estoppel. It seems clear that parties are not estopped by a judgment or barred by prior recovery from contesting an interference involving a claim of patentably different scope from the claim or claims the right to which have been adjudicated. The rule of estoppel in pais, equitable estoppel, or estoppel by conduct has been availed of as a guide for preventing improper second interferences. Henderson, 50 App. D. C. 191; 269 Fed. 707; 284 O. G. 182; 1921 C. D. 133. This form of estoppel is stated by Bigelow, cited, on page 602 to apply to "cases "in which one man has *** caused another to believe "something which afterwards it would be unjust for the

former to repudiate." It is stated in 21 Corpus Juris 1119 that in order to constitute such an estoppel "there "must exist a false representation or concealment of "material facts; *** the party to whom it was made. "must have been without knowledge or the means of knowledge of the real facts; it must have been made. "with the intention that it should be acted upon;

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***

As the term estoppel by conduct or in pais, is elsewhere used in the law, a second interference would rarely if ever be barred by estoppel, because the element of actual or constructive deception is nearly always absent. See In re Martin, 48 App. D. C. 187; 257 O. G. 408; 1918 C. D. 213. The Henderson decision cited, presents special facts, which constituted an estoppel by conduct.

Other equitable doctrines. Several other equitable doctrines are closely related to estoppel by conduct. Laches will be considered separately. Waiver might, perhaps be utilized, altho it has not generally been applied to questions of how a party's rights are affected by previous litigation in which he was himself involved. Bigelow, cited, chap. XIX. 21 Corpus Juris, 1202-1223; 1341. Furthermore it seems to involve deliberate action or inaction, which is not found in the patent cases. Election applies only to inconsistent positions. Bigelow, chap. XX. 21 C. J. 1222-1240. There is no inconsistency in asserting patent claims of different scope.

Laches. It has been seen that neither res judicata nor estoppel should prevent an applicant from obtaining a second interference with the same adversary, on the same disclosures, when the proposed second interference involves a patentably different count. It has also been recognized that such interferences should sometimes be refused. Perhaps there is no necessity for basing such refusal upon any of the rules of law or equity that are applied to ordinary litigation. There is no absolute reason why the refusal might not be based upon rules peculiar to patent practice, utilizing, if necessary, new nomenclature. The human mind, however, seeks to correlate new things with old ones, and the legal mind prefers to follow familiar doctrines, when possible. It is, perhaps, possible to do this by utilizing the doctrine of laches.

Definitions. Of the numerous definitions found in "Words & Phrases", second series (1914), vol. 2 pp. 1327-1333, only one is quoted. This calls laches "such "neglect or omission to assert a right as, taken in con"junction with lapse of time more or less great, and other

circumstances causing prejudice to an adverse party, "operates as a bar in a court of equity." 18 Am. v. Eng. Enc. of Law, 2d ed., 97, quoted in Wright v. Simpson, 200 Ill. 56, 65. Under the topic "Equity" in 21 Corpus Juris 231, it is stated that: "If, in the course of an inexcusable delay in the assertion of a right, changes occur in the subject matter of the transaction in suit or in the relative position of the parties thereto, as a result of which it is impossible to place the parties in statu quo, and the enforcement of the right would work inequity, relief will be denied because of laches." Numerous cases are cited from lower tribunals, and two from the Supreme Court, neither of which is particularly helpful for patent inter ference problems, and one of which seems to be based on waiver rather than laches.

Difficulties. It is recognized that the general doctrine of laches is not perfectly satisfactory as a tool for dealing with this problem. In particular it has been used less with reference to the effect or prior determination than as the equivalent in equity of statutes of limitation. But it seems to the writer somewhat less irrelevant that res judicata, waiver, or the various forms of estoppel. Actually these are not watertight compartments, but rather they are overlapping areas in the general region. of things that the human mind apprehends as unjust.

Factors. It is not desirable that rigid rules should be established as to when an applicant should be allowed claims that will probably lead to a second interference with the same adversary on different counts. This is particularly true at the present time when the subject matter is in the formative stages. After a larger number of cases have been decided, the material will be available to lay down more definite rules. There are, however, a number or outstanding factors, which have been potent in adjudicated cases. Delay is, of course, preeminent among these. Others are: (a) whether the parties had access to each others applications during the interference; (b) comparative breadth of old and new counts; (c) whether successful or unsuccessful party is urging

new counts; (d) whether the proposed new counts were present as claims in either case or both during interference; (e) if they were present in some case whether they were indicated as allowable; (f) whether the proposed counts are now patented to either party; (g) demand during first interference for additional interference; (h) whether there is evidence in the first interference that there would be a different result on the proposed new

counts.

Access. If the first interference was terminated under rule 107, so that neither party had access to the others application, the judgment never bars an interference on different issues, so far as the reported cases indicate. Felsing v. Nelson, 20 Gourick 6:12 (1907), affirmed, 32 App. D. C. 420; 142 O. G. 289; 1909 C. D. 358. Reed v. Cropp, 239 Fed. 869; 240 O. G. 1449; 1917 C. D. 321 (C. C. A.-7).

Narrower claims. With possible exceptions when the claims have been in the adversary's case and not in the successful party's case, the successful party would always be allowed narrower claims. Van Yorx, 170 O. G. 243; 1911 C. D. 97. It would seem unwise to declare a second interference on the application because there is so little liklihood of a different result, altho one decision indicates that an interference might be declared. Clements v. Kirby, 274 Fed. 575, 584; 292 O. G. 879; 1921 C. D. 319 (C. C. A.-6). After the grant of the patent, if the losing party should make a prima facie showing that he could win on the narrower count, he might be given an interference with the patent.

Correspondingly the losing party should be refused narrower claims unless the claims were in his application and not in his adversary's during the first interference, or unless there is a special showing of a probable different result on the narrower counts. Carroll v. Hallwood, 31 App. D. C. 165; 135 O. G. 896; 1908 C. D. 444. Cutler, 232 O. G. 939; 1916 C. D. 1 (Examiners in chief). Curtiss, 46 App. D. C. 183; 238 O. G. 650; 1917 C. D. 142. In the last named decision the claims seem to have been

actually broader, but the court treated them as more restricted. In the Cutler case they were broader, but if broader claims may be allowed, narrower ones certainly could be.

Broader claims. With some doubt it is submitted that broader claims should rarely be allowed to either party. Sutton, Steele, & Steele, 121 O. G. 1012; 1906 C. D. 111. Consider also the statement in Horine v. Wende, 129 App. D. C. 415, 428; 129 O. G. 2858; 1907 C. D. 615, 624. A decision on this subject by the examiners in chief is believed to be inconsistent with the spirit of the other cases. Klahn, 241 O. G. 623; 1917 C. D. 7. (Decided 1905). The opinion of the board, that there is no direct statutory basis for rejection, is correct. But the express statutory grounds for rejection are not exhaustive. The situations discussed in this paper are closely analogous to rejections on delayed reissues, or for delay in copying claims of a patent. In neither of these is there a statutory ground for rejection. The fact that two species were disclosed in the application seems to have confused the board, in the Klahn case. Actually it was quite irrelevant. Probably it is usual, rather than exceptional, for inventors to embody their inventions in a variety of forms. Often, however, they disclose only a single embodiment in their application. But this should have no bearing on their right to priority. Klahn might have been earlier on the species not involved in interference than on the one that was involved. His adversary might have been still earlier on some third species. But Klahn's laches in failing to present broad claim during the interference should have barred him in the absence of other circumstances than those mentioned in the opinion. The decision, however, was made nearly twenty years ago, prior to all except three or four of the other patent cases cited in this paper. It would probably not be followed by any tribunal at the present time.

Claims in application during interference. If the claims were in the case during interference the only laches has been the failure to move under rule 109 to have them