This appeal is from a decision of the Patent and Trademark Office Board of Appeals affirming the examiner's rejection of all claims remaining in an application to reissue a patent.
The first ground was, speaking generally and in the words of the board, a rejection "(1) Under 35 U.S.C. 251," the statute authorizing reissue of defective patents. That statute reads, in pertinent part:
In his first action on the reissue application the examiner rejected all claims under § 251 for two reasons. First, the examiner said that in view of the decision of the Court of Appeals in Beckman Instruments, Inc. v. Chemtronics, Inc., 428 F.2d 555 (5th Cir.), cert. denied, 400 U.S. 956, 91 S.Ct. 353, 27 L.Ed.2d 264 (1970), "applicant is not deemed to have satisfied the statutory requirement of a lack of `deceptive intention'." Second, the examiner said that in view of the
"reissue would not be proper."
After considering extensive arguments by appellant, the examiner, in his final rejection, repeated and adhered to both of his reasons for rejecting all claims under § 251. As to the first reason he said,
As to the second reason, he reiterated that making more explicit structural features already implicit in claims "is not a proper basis for seeking reissue."
In his Examiner's Answer, responding to appellant's appeal brief, the examiner pointed out, inter alia, that this application is to reissue a patent involved in a litigation in which the Fifth Circuit Court of Appeals had held the patent invalid because of plaintiffs' (the plaintiffs being appellant and his exclusive licensee, by whom the application for the patent sought to be reissued had been prosecuted) "failure to fulfill the `uncompromising duty' of full and good faith disclosure to the Patent Office." That failure resided in not disclosing to the Patent Office the Stow et al. publication, well known to plaintiffs at the time and clearly known to them to be of pivotal importance in determining the patentability of Clark's claims.
As the examiner had done previously, he equated the deliberate failure to disclose the Stow et al. reference to the Patent Office with failure to comply with § 251, which requires that whatever the defect in the patent may be it shall have occurred "through error without any deceptive intention." He then concluded:
And, summarizing his previously-stated second reason for noncompliance with § 251, he said:
The board, in affirming the rejection under § 251, said (emphasis added):
The opinion of the Fifth Circuit Court of Appeals, in the suit above referred to, summarized the court's decision on validity of the patent sought to be reissued by saying, in part:
The court followed up that statement with a full discussion of the second ground in section II B of its opinion wherein it said, inter alia, after reciting the facts with respect to the knowledge and relevance of the Stow et al. reference:
It was appropriate that the examiner should have given initial consideration to the question of whether a proper ground for reissue existed under § 251. That is the first order of business in examining an application for reissue. Stringham, Patent Soliciting and Examining, Sec. 297, pp. 577-78 (1934); McCrady, Patent Office Practice, Sec. 222 (4th ed. 1959); Manual of Patent Examining Procedure 1401.08. This entails a consideration of the grounds stated in the reissue oath or declaration on the basis of which reissue is sought. Only after that hurdle has been cleared is it necessary to consider the issues of patentability of the reissue claims over prior art, as developed on further examination of new or amended claims or reexamination of retained patent claims. See 37 CFR 1.175 and 1.176.
The instant application does not clear the first hurdle and its rejection must be affirmed on that ground. It is therefore unnecessary to consider other questions discussed in the briefs and arguments.
This opinion is sharply focused on the single question of whether appellant has presented a good case for reissue of his patent under § 251.
Claims 1, 2, 6, 7 and 8 are the only claims on which he appealed to the board and on which he appeals here. As the board found, claims 2 and 8 are the same as claims of the patent. Appellant admitted before the board that the remaining claims are "in substance" the same as claims in the patent. This is in accord with the allegation in the reissue declaration with reference to all of the claims initially contained in the reissue application (many of which were cancelled) "that the purpose of this reissue application is to amend certain claims in order to make more explicit structural features already implicit in those claims * *." (Emphasis added.) Appellant's Reply Brief before the board similarly admits: "It is true that the claims on appeal are in substance claims which were in the original patent." We see no change in the subject matter delineated by these "changed" claims.
Simple logic forces the conclusion that appellant never thought he was claiming "more or less than he had a right to
It being apparent that in filing his application for reissue appellant asserted no defects in the specification, drawing, or claims, it may well be asked what his purpose was. Considering the substance of the reissue declaration, it clearly constitutes an argument as to the differences between what he claimed in his patent and the prior art, particularly Stow et al., and a justification of his failure to call the Stow et al. reference to the attention of the Patent Office. The declaration amounts to nothing more than an argument that the Fifth Circuit Court of Appeals erred in holding his patent claims invalid over prior art and a request that the Patent Office issue him a new patent (with specification and claims unchanged "in substance") over the art on which the court relied, of which art the Office, by virtue of the litigation, is now, of course, fully informed.
Appellant has failed to comply with § 251 because he has not cleared the condition that the patent be inoperative or invalid through some "error." Appellant has pointed to no error on his part but only to alleged error by the Fifth Circuit Court of Appeals.
In the Fifth Circuit litigation, the patent was held invalid on two grounds: (A) unpatentability over Stow et al. and (B) Clark's failure to disclose the Stow invention to the Patent Office. The latter point is controlling here, because if it does not fall within the concept of "error" in § 251, it negatives the right to reissue apart from all other considerations. Ground (B), furthermore, goes to the patent right as a whole, independently of particular claims.
The holding of invalidity of the Clark patent on ground (B) was not because of any defect in the patent or the unpatentability of any claim but because of inequitable or at least impermissible conduct on the part of the applicant, or on the part of those he entrusted with the prosecution of his application, by whose acts he is bound under elementary legal principles.
The failure to disclose Stow et al. to the examiner resulted in the Fifth Circuit deeming appellant's patent to be invalid, and it is this act, whether the Fifth Circuit was correct or not, which impelled appellant to seek a reissue. We cannot accept appellant's argument that the failure to disclose was an error in the sense that it arose by inadvertence, accident, or mistake. See In re Wadlinger, 496 F.2d 1200 (CCPA 1974). The record, which includes the evidence before the Fifth Circuit as well as the papers in the instant reissue application, shows that Beckman, appellant's agent,
While appellant may have believed that Stow et al. was not a relevant reference, the Patent and Trademark Office now has ample evidence from which to conclude that Stow et al. was known by Beckman to be highly relevant prior art. The duty to disclose relevant, material prior art under these circumstances, known to the applicant or his agents and not found by the examiner, is well established. The Strickler memorandum shows how relevant and material Beckman considered Stow et al. to be. If appellant considered his claims sufficiently narrow to be clear of the close Stow et al. reference, the examiner, and not he or "others skilled in this art," was the person to decide whether appellant's original claims had been amended sufficiently to be patentable over Stow et al. We do not agree that appellant could, under the state of the law in 1956 or now, amend claims expressly to avoid a § 102 reference unknown to the examiner and justifiably consider there was no duty to bring that reference to the examiner's attention. We see no error, accident, inadvertence, or mistake in these facts.
Reissue is not available to rescue a patentee who had presented claims limited to avoid particular prior art and then had failed to disclose that prior art (the examiner not having cited it) after that failure to disclose has resulted in the invalidating of the claims. The sole goal of appellant in soliciting a reissue is to have the examiner re-examine his claims in light of the reference he originally failed to disclose in order, apparently, to relieve him of the consequences of his failure.
While this court has often said that § 251 is to be liberally construed as a remedial statute, In re Oda, 443 F.2d 1200, 58 CCPA 1353 (1971), we do not feel that such liberalism extends to eradication of a dereliction of a duty by what is, in effect, a re-prosecution in which the examiner is now given an opportunity to pass on patentability in light of a very pertinent reference which the applicant knowingly withheld from him. We cannot equate this with "error," or with "inadvertence, accident, or mistake."
Walker Process dealt with an allegation of fraudulent procurement of a patent and with the traditional elements of fraud. The district judge's opinion on remand in Beckman found them missing. Like the two opinions in Walker Process, he distinguished honest mistake and other bona fide actions with respect to matters which may result in patent invalidity—sometimes classified as "technical fraud," which is not fraud at all. Appellant would have us put his conduct in the latter category and on that basis accord to him the right to overcome his failure to perform his uncompromising duty through reissue, holding it was just an "error" under § 251. That we will not do. The attempt comes to late. Even though it is not fraud, an applicant or his agent cannot knowingly withhold relevant prior art from the examiner until he finds out whether such action invalidates his patent and then apply for reissue only if he loses the gamble on the ground he made an "error." When, as here, a holding of invalidity has been decreed by a court of appeals for a flagrant dereliction of duty to disclose, reissue is not available for expiation.
The decision of the board is affirmed.
MILLER, Judge (concurring).
I agree that the decision of the board affirming the examiner's rejection should be affirmed. However, I would affirm on the ground of collateral estoppel based on the Fifth Circuit's holding of unpatentability in Beckman. I disagree with the majority's affirmance of the board's decision on the ground of failure to meet the requirements of § 251.
§ 251 ISSUE
The only "hurdle" presented by § 251 is that the patent, "through error without any deceptive intention, [be] deemed wholly or partly inoperative or invalid by reason of a defective specification or drawing, or by reason of the patentee claiming more or less than he had a right to claim in the patent . . . ." If this "hurdle" is cleared, "the Commissioner shall . . . reissue the patent . . . ." (Emphasis supplied.)
Appellant's patent was deemed invalid by the Fifth Circuit by reason of his claiming more than he had a right to claim. Thus, the Fifth Circuit has established appellant's error. The § 251 issue, therefore, is whether the error was "without any deceptive intention."
The majority would ignore this error by creating two "hurdles" not required by the statute: (1) It implies that an applicant for a reissue patent must have thought he was claiming more or less than he had a right to claim in the patent, saying:
(2) Giving a narrow, technical construction to appellant's reissue declaration, without examining the claims in detail, it declares that claiming "more or less than he had a right to claim in the patent" could not have been the statutory reason for applying for reissue, because appellant "admitted before the board" that claims 1, 6, and 7 were the same "in substance" as claims in the patent.
However, an examination of claims 1 and 6 shows that they have been changed in scope. Claim 1, which originally claimed a device merely with "means for confining an electrolyte forming substance," now requires such a substance. Claim 6, which originally claimed merely a means "adapted to contain an electrolyte," now requires an
It is clear that appellant relies on the "error" established by the Fifth Circuit as a basis for filing for reissue. His declaration states:
During prosecution, appellant explained this portion of his declaration as follows:
Contrary to the majority's implication that no changes in the claims were made until after rejection of the reissue application, some of the claims originally set forth in the reissue application (and cancelled by an amendment under Rule 116, 37 CFR 1.116, that also amended other claims which are on appeal) were changed from those in the patent. Thus, viewing appellant's statements and actions in full context, it is clear that he intended to limit the scope of the claims to avoid the prior art. The narrow construction given by the majority to the statement in the reissue oath that the purpose of the application was to make more explicit structural features already implicit in the patent is not in keeping with the liberal approach that should be followed in applying a remedial statute. In re Oda, 443 F.2d 1200, 58 CCPA 1353 (1971). This is particularly true considering the Fifth Circuit's conclusion that his patent claimed the broad concept of the dual electrode within a permeable membrane for use covering the broad field of polarography rather than particular forms of a polarographic device.
Another error relied upon by appellant and recognized by the majority is his failure to call the Stow invention to the attention of the Patent Office (PTO). This "error" or "mistake in judgment" was a ground relied on in Beckman for the holding of invalidity. The fact that it was deliberate does not preclude reissue. In re Wadlinger, 496 F.2d 1200 (CCPA 1974).
After explaining some of the circumstances surrounding this error, the majority asserts, without citation of authority, that reissue is not available to rescue a patentee who had presented claims limited to avoid particular prior art and had failed to disclose that prior art—after such failure to disclose has resulted in invalidating the claims. But, in the absence of any contrary provision in the statute, reissue should be available to remedy any error or mistake made by applicants and their attorneys without deceptive intent. See Fontijn v. Okamoto, 518 F.2d 610, 622 (CCPA 1975).
The majority does not directly state that the above errors are unavailable to appellant because of "deceptive intention," but this appears to be the real basis for its decision.
The majority says that an applicant cannot wait until he finds out that his actions have invalidated his patent before applying for reissue. However, before the patent was declared invalid, appellant was unaware that it was defective and, therefore, could not have cleared a hurdle that is in § 251. The majority gratuitously labels appellant's conduct a "flagrant dereliction of duty," but the Fifth Circuit in Beckman did not so characterize it; and the finding of the district court that appellant acted in good faith stands in sharp rebuttal.
The majority quotes the examiner's reference to the Fifth Circuit's determination of invalidity of the Clark patent for failure to fulfill the uncompromising duty of full and good faith disclosure to the PTO and states that such failure "resided in not disclosing to the Patent Office the Stow et al. publication, well known to plaintiffs at the time and clearly known to them to be of pivotal importance in determining the patentability of Clark's claims." It refuses to
The cited case was an action for an infringement and breach of contract brought by Automotive against Precision and one Kenneth Larson. In 1939, what was then the Patent Office declared an interference between certain claims in Larson's pending patent application and those in one filed by one Herman Zimmerman. Automotive was the owner of Zimmerman's application. In Larson's preliminary statement before the Patent Office he gave false dates regarding conception, disclosure, drawing, description, and reduction to practice of his claimed invention—all designed to antedate those in Zimmerman's application. Larson and eight witnesses also testified in the interference proceedings in support of his claims, corroborating his statement regarding dates. With knowledge of the falsity of the statement and testimony, the parties worked out a settlement in which Larson conceded priority to Zimmerman and Larson's application (owned by a third party) was to be assigned to Automotive. The assignment took place, and automotive received patents on both the Larson and Zimmerman applications. The defense against Automotive's subsequent infringement suit was that Automotive possessed such "unclean hands" as to foreclose its right to enforce the patents and the contracts. In reversing the Seventh Circuit and holding that the district court's dismissal of the complaints "for want of equity" was correct, the Supreme Court applied the equitable maxim that "he who comes into equity must come with clean hands." It said:
It was in this context that the Supreme Court laid down the "uncompromising duty" standard as follows:
It is readily apparent that the facts in the Precision Instrument case and the full statement of the "uncompromising duty" standard are not applicable to the case before us. As the district court
The majority makes the broad statement: "The duty to disclose relevant, material prior art under these circumstances, known to the applicant or his agents and not found by the examiner, is well established." I respectfully point out that the duty to disclose as it existed during the period 1956-1959 (from the time of application to issue of the original patent) is what should be established. As one recognized authority has put it, "would the average patent solicitor prosecuting the Clark reference have felt that he had in Stow a section 102 reference which must be cited to the examiner or a section 103 reference which need not be set up as a straw man?"
COLLATERAL ESTOPPEL ISSUE
The examiner's second ground of rejection was the holding of the Fifth Circuit Court of Appeals that the claims were unpatentable over Stow et al., the claims in the reissue application being "not in substance different from the claims held invalid by the Court of Appeals." Although the examiner cited Blonder-Tongue Laboratories, Inc. v. University of Illinois Foundation, 402 U.S. 313, 91 S.Ct. 1434, 28 L.Ed.2d 788 (1971), the board did not do so, saying merely that the Fifth Circuit's holding of unpatentability in Beckman Instruments, supra, "is necessarily controlling as to the patentability of the claims here on appeal." Because of lack of identity of parties and difference in actions before the PTO and those before the Fifth Circuit,
The court emphasized that the ex parte proceeding bore "such a close relationship" to the prior inter partes (interference) proceeding that estoppel was properly applied with respect to questions that were, or should have been, answered in the priority contest. There is a similar close relationship between a reissue proceeding under 35 U.S.C. § 251 and a prior infringement proceeding where the issue of patentability decided in the infringement proceeding prompted the filing of the reissue application.
An essential element of the rule of collateral estoppel is substantial identity of the issue or issues in each action. Partmar Corp. v. Paramount Pictures Theatres Corp., 347 U.S. 89, 74 S.Ct. 414, 98 L.Ed. 532 (1954); see Carter-Wallace, Inc. v. United States, 496 F.2d 535 (Ct. Cl.1974). Thus, the public interest in granting valid patents (including reissued patents) outweighs the public interest underlying collateral estoppel and res judicata where "the issue" presented is not substantially identical. In re Russell, 439 F.2d 1228, 58 CCPA 1081 (1971); In re Craig, 411 F.2d 1333, 56 CCPA 1438 (1969). It is therefore necessary to review the Fifth Circuit's opinion in Beckman in light of the record before it to determine whether the issue of patentability there was substantially the same as that involved in appellant's reissue application proceeding. Needless to say, appellant vigorously maintains that the issue is not substantially the same; that, indeed, the Fifth Circuit's decision on unpatentability over the prior art related only to claims 9 and 10.
The original complaint of Beckman and Clark alleged infringement of the patent generally, without specifying any claims. Defendants' "Answer and Counterclaim" alleged, among other things, invalidity of the patent generally, on the
During the trial, plaintiffs' counsel made the following statement:
Thus, plaintiffs did not dismiss their suit with respect to claims 3-5. Even had they sought to do so, the solicitor argues persuasively that this would not "immunize those claims from defendants' noted counterclaim for patent invalidity." Kalo Inoculant Co. v. Funk Bros. Seed Co., 161 F.2d 981 (7th Cir. 1947), rev'd on other grounds, 333 U.S. 127, 68 S.Ct. 440, 92 L.Ed. 588 (1948); Schering Corp. v. Gilbert, 153 F.2d 428 (2d Cir. 1946); Lackner Co. v. Quehl Sign Co., 145 F.2d 932 (6th Cir. 1944). The trial court held that "the invention of the patent in suit" was neither anticipated for purposes of 35 U.S.C. § 102 nor obvious to one skilled in the art for purposes of 35 U.S.C. § 103. It also held that there had been no infringement. 160 USPQ 619 (W.D. Tex.1968).
Before taking up the issues on appeal, the Fifth Circuit noted the Supreme Court's emphasis on the desirability of determining patent validity in an infringement suit even though the simplest way to dispose of the case would be a finding of non-infringement. It cited Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 S.Ct. 1143, 89 L.Ed. 1644 (1945), where the Court said:
The court proceeded to "find the patent sued upon . . . to be invalid for two independent reasons," namely: "anticipation" by Stow (without citing 35 U.S.C. § 102 or § 103),
The court premised its holding of "anticipation" on its determination that Stow was the inventor of the "broad concept of the dual electrode within a permeable membrane" not only for use in potentiometric cells, but for use with electrochemical cells generally (which would include polarographic cells).
The court concluded, "after having examined the claims at suit," that appellants had attempted to claim a patent "monopoly" on use of Stow's "broad concept" in the entirety of an established, generalized field of analytical chemistry, and it stated in note 17 that "[t]he claims sued upon in this case are numbers 9 and 10 of appellants' patent." However, the opinion as a whole indicates that the court was aware that validity of all claims of Beckman's patent had been put in issue by Chemtronics and that its holding on "anticipation" by Stow was not restricted to claims 9 and 10. In note 10, for example, the court said: "Several of the claims do not contain the word polarography or any other language that would limit them to that field." (Emphasis supplied.) This could only refer to claims other than claims 9 and 10, which contained such language.
In view of the foregoing, I am satisfied that the Fifth Circuit held all patent claims unpatentable over Stow. It should be pointed out, however, that, for purposes of collateral estoppel, absolute identity of the claims, as opposed to "the issue," is not required. See Westwood Chemical, Inc. v. Molded Fiber Glass Body Co., 498 F.2d 1115 (6th Cir. 1974).
Next it must be determined whether appellant's specification and/or claims in his reissue application have been changed sufficiently to avoid substantial identity of the issue relating to unpatentability over Stow. In other words, the question is whether the changes present an issue that was not adjudicated by the Fifth Circuit.
The specification has been amended to limit the description to polarographic cells. However, in Beckman the Fifth Circuit said "we assume, as appellants have urged that we should, that the patent covers only devices for polarographic analysis."
With respect to the claims in the reissue application, claims 2 and 8 are identical to the patent claims.
Claims 6 and 7 have been amended to add the word "direct," which, as just noted, is inherent in a polarographic device. Adding a requirement of an "electrolyte" does, as pointed out above, change the scope of claim 6. However, since this requirement was also present in original claim 2, it does not present an issue not adjudicated by the Fifth Circuit. Other amendments to claims 6 and 7 express insubstantial limitations inherent in the subject matter of the claims.
Accordingly, I conclude that the changes in appellant's specification and claims in his reissue application are insufficient to avoid substantial identity with the issue adjudicated by the Fifth Circuit.
In view of the foregoing, I would hold that the board correctly applied the rule of collateral estoppel in affirming the examiner's rejection of the claims.
Thereafter, Beckman amended the claims in an attempt to avoid the Stow et al. reference and prosecuted the application to issuance without disclosing Stow et al. to the examiner, who did not discover it on his own.
4. As held by the Court of Appeals, some of the claims in the Clark patent are improperly drawn in that they cover the Stow arrangement simply put to a "different use" (428 F.2d at pp. 561, 564, 165 USPQ at 360, 562-563 [sic 362-63]). This does not mean, however, that the invention of Dr. Clark is the same as the Stow device. That they are different was readily admitted by defendants' expert Dr. Bard (R. 579, 606), and also by defendant Neville (R. 667). The basic differences in function and structure, as contrasted with the apparent similarities, were described in detail by Dr. Hume (R. 505-512). The Court of Appeals held that plaintiffs nevertheless should have called the Stow device to the attention of the patent examiner, as relevant to the broad claims of Clark. However, on the remand issue, i. e., whether plaintiffs committed an "intentional fraud", the acknowledged and significant differences between the Clark and Stow devices support plaintiffs' position that they acted in good faith and simply made an "honest mistake in judgment". [Footnote omitted.]
. . . . .
6. In holding the Clark patent invalid because of plaintiffs' failure to call to the attention of the Patent Examiner the prior carbon dioxide detection device of Dr. Stow, the Court of Appeals emphasized a memorandum from Beckman's patent liaison employee Strickler, dated December 6, 1956 (Defendants' Exh. N-48). In this memorandum Strickler stated that claims then pending in the Clark application read upon the Stow device, that he did not know which of the two developments was earlier, and that he was concerned over the situation. As the Court of Appeals held, the Strickler memorandum showed his knowledge of the Stow development, and his realization that there might be a problem if Dr. Clark obtained patent claims broad enough to cover Stow's glass electrode device. It was true, moreover, that not all of the claims pending in the Clark application at the time of the Strickler memorandum contained a polarographic limitation and, if read without resort to the patent specification, one or more of these claims covered the Stow device. With respect to the issue of plaintiffs' good faith a significant fact, however, is that all of these original claims were cancelled during the prosecution of the Clark patent application (Defendants' Exh. A) and, as held by the Court of Appeals, "under the rules of patent construction" the patent finally obtained "covers only devices for polarographic analysis" (428 F.2d at p. 562, 165 USPQ at 361). The Strickler memorandum, particularly when considered in light of the patent prosecution as a whole (Defendants' Exh. A) and the patent ultimately issued to Dr. Clark, does not suggest any intent or plan to obtain a patent which would cover the Stow device.
7. The Strickler memorandum also states that the Stow device was a "glass electrode adaptation that he was developing for pCO
8. There was testimony at the trial that Beckman never demanded a royalty under the Clark patent on any device for measuring carbon dioxide, and that Beckman has never paid Dr. Clark any royalty on Beckman's carbon dioxide measurement devices (R. 370, 398). This further shows that Beckman's interpretation of the scope of the Clark patent, as excluding the Stow and other carbon dioxide detection devices, was consistent with the holdings of the Court of Appeals and this Court that the Clark patent was limited to devices for polarographic analysis.
9. The evidence as a whole shows a good faith belief on the part of plaintiffs that instruments for polarographic analysis, such as the Clark oxygen cell, were basically different and patentably distinct from potentiometric carbon dioxide detection devices such as Stow's glass electrode. The testimony of Dr. Hume (R. 505-512) and the deposition testimony of Dr. Severinghaus (R. 341-344) shows that acknowledged experts in polarographic and potentiometric analysis considered the Stow potentiometric carbon dioxide device and the Clark polarographic oxygen cell to be independent and distinct developments. Dr. Severinghaus, after attending the meeting at which Stow first disclosed his membrane covered glass electrode for carbon dioxide detection, and discussing it with Dr. Stow, continued working in an effort to solve the independent problem of polarographic oxygen measurement until Dr. Clark disclosed his solution (R. 325-328). The opinions and actions of scientists directly involved in these fields corroborate plaintiffs' position that they were acting in good faith in relying upon the differences between polarographic and potentiometric analysis.
10. The court finds that defendants have not made a prima facie showing of Walker Process intentional fraud because the evidence shows that plaintiffs had a good faith belief that the polarographic analysis to which the Clark patent is limited sufficiently distinguished the Stow potentiometric development and made it immaterial.
. . . . .
19. The record as a whole shows that plaintiffs acted in good faith in obtaining and seeking to enforce the Clark patent in suit. The "significant differences between the Clark and Stow devices" are apparent. The Clark device measures current and therefore is polarographic; whereas the Stow device measures voltage and therefore is potentiometric. The Clark device utilizes a fixed voltage with electrodes of relatively low resistance to permit current flow; whereas the Stow device utilizes a glass electrode of extremely high resistance to approach an ideal current of zero. These and other significant differences led Dr. Hume, one of the expert witnesses before the District Court to compare the superficial similarities to those between a cow and a cat.