See, e.g., In re Montgomery, 677 F.3d 1375, 1383 (Fed. Cir. 2012) (Lourie, J., dissenting) ("Inherency is a very tricky concept in patent law."). As an initial matter, the parties' dispute raises the question of how courts determine whether a limitation is directed to a new use of a known process, or is instead merely a newly discovered, yet inherent result of a known process.

The structure of the '903 patent claim 1 is therefore not comparable to the structure of patent claims in which statements of general purpose in the preambles of method claims have been held to carry no patentable weight. E.g. , Bristol-Myers Squibb Co. v. Ben Venue Labs., Inc. , 246 F.3d 1368, 1375 (Fed. Cir. 2001) (preamble phrase "for reducing hematologic toxicity" was "non-limiting, and merely expressing a purpose"); see also In re Montgomery , 677 F.3d 1375, 1380 (Fed. Cir. 2012) (expressing "skeptic[ism]" that the phrase "for the treatment or prevention of stroke" in a claim preamble was more than an expression of purpose for the claimed method).Other intrinsic evidence shows that the "arresting or regressing" limitation does not merely duplicate the wherein clause that follows.

E.g., In re Montgomery, 677 F.3d 1375, 1379-80 (Fed. Cir. 2012). It construed claim 1 to recite a process of treating raw water with (1) "at least some amount, however small, of any manner of one of the specified aluminum polymers, including any manner of aluminum chlorohydrate" and (2) "at least some amount, however small, of any cationic ammonium polymer compound having a molecular weight falling within the molecular weight range 'of at least about 500,000 to 1,000,000.'" Haase, at *3-4.

“A reference may anticipate inherently if a claim limitation that is not expressly disclosed is necessarily present, or inherent, in the single anticipating reference.” In re Montgomery, 677 F.3d 1375, 1379-80 (Fed. Cir. 2012) (internal quotation marks omitted). “[I]nherent anticipation does not require a person of ordinary skill in the art to recognize the inherent disclosure in the prior art at the time the prior art is created.”

(Id. at 6-7) Neither party identified much pertinent caselaw, so the Report turned to In re Montgomery, 677 F.3d 1375 (Fed. Cir. 2012), and found by analogy that here a factual dispute exists as to whether the disclosure in Kelly is "too theoretical" to be enabling (Report at 43). Dicta in Montgomery differentiated between a mere "invitation to investigate" or "abstract theory," both of which may not be sufficiently enabling for anticipation, and the reference at issue in Montgomery, which disclosed "an advanced stage of testing designed to secure regulatory approval."

"A reference may anticipate inherently if a claim limitation that is not expressly disclosed is necessarily present, or inherent, in the single anticipating reference." In re Montgomery , 677 F.3d 1375, 1379–80 (Fed.Cir.2012) (internal quotations omitted). The Federal Circuit has explained that an inherent limitation is one that is necessarily present and not one that may be established by probabilities or possibilities.

Hugh E. MONTGOMERY, et al., petitioners, v. David J. KAPPOS, Under Secretary of Commerce for Intellectual Property and Director, Patent and Trademark Office.Case below, In re Montgomery, 677 F.3d 1375. Petition for writ of certiorari to the United States Court of Appeals for the Federal Circuit denied.

We have previously held that "[n]ewly discovered results of known processes directed to the same purpose are not patentable because such results are inherent." In re Montgomery, 677 F.3d 1375, 1381 (Fed. Cir. 2012) (citation omitted); see also In re Huai-Hung Kao, 639 F.3d 1057, 1070-71 (Fed. Cir. 2011) (holding that a "food effect" was obvious because the effect was an inherent property of the composition). While mechanisms of action may not always meet the most rigid standards for inherency, they are still simply results that naturally flow from the administration of a given compound or mixture of compounds.

. . ." In re Montgomery, 677 F.3d 1375, 1379 (Fed. Cir. 2012) (quotation omitted); see also Cuozzo Speed Techs., LLC v. Lee, 136 S. Ct. 2131, 2146 (2016). We review the Board's ultimate claim construction de novo.

Rather, "[t]he inherent result must inevitably result from the disclosed steps...." In re Montgomery , 677 F.3d 1375, 1380 (Fed. Cir. 2012).B. The District Court's Finding