Silence in a reference can sometimes be anticipation

Takeaway: Can a reference that is silent about a limitation can nonetheless anticipate the limitation? It is possible. It depends on how the reference would be understood by a POSITA, and specifically, what inferences a POSITA would draw from the silence. This usually comes up in the context of a negative claim limitation, e.g., a reaction occurring "without application of heat." The mere fact that the reference is silent about the application of heat, or even silent about temperature, is not enough. However, if a POSITA reading in between the lines understands the reference as a whole to describe a reaction at room temperature, then the reference does indeed anticipate "without application of heat."

Details: In the general topic of anticipation by silence in a reference, there are two lines of cases. One deals with inherency, and the other with implicit teachings. For purposes of this post, I'm not interested in inherency. Once you realize that the Examiner's position on the silent reference is based on inherency, you can deal with that by applying inherency case law.

I'm interested instead in cases where the reference is silent as far as an explicit teaching goes, but where the real issue is the implicit teachings. Several Federal Circuit cases that discuss "silence" in a reference boil down to the same general principle: whether a reference that is silent on a point nonetheless anticipates depends on how the reference would be understood by a POSITA, and specifically, what inferences a POSITA would draw from the silence.

One case that is often cited in discussions about silence in a reference is Upsher-Smith Labs., Inc. v. Pamlab, 412 F.3d 1319, 1322 (Fed.Cir.2005). Upsher-Smith holds that a teaching that a step is optional anticipates a claim that specifically excludes the step. The way I see it, the reference in Upsher-Smith is best understood as teaching two embodiments: one that includes the step; and one that excludes the step. Far from being completely silent on the claimed limitation, the reference in Upsher-Smith comes close to an explicit teaching of the claimed element.

The Federal Circuit case that I think best explains how silence in a reference can nonetheless anticipate is In re Baxter Travenol Labs, 952 F.2d 388 (Fed. Cir.1991). In Baxter Travenol, there was no express teaching of the claimed limitation, but the court found that a POSITA would have nonetheless understood the reference as implicitly teaching the limitation. The claim in Baxter Travenol recited two bags for collecting and storing blood, each bag made of a different specific material. Instead of specifically stating the material for the donor bag, the reference instead described the bags as compared to existing technology. A POSITA could draw an inference about the material of the donor bag from this comparison:

In describing its blood bag system, the Becker document makes two references to then-available commercial blood bag systems. The most significant reference is on page 49, where Becker describes his double blood pack system design as "very similar to [Baxter] Travenol's commercial, two bag blood container. The exception is that the secondary transfer pack was a 350 ml Teflon container...." ...

Testimony ... established that Baxter's commercial systems during this time period all contained a primary bag plasticized with DEHP. Therefore, since Becker referred to Baxter's commercial system and Baxter's commercial systems utilized a DEHP-plasticized primary bag, it is clear that one skilled in the art would have known that Becker was referring to a DEHP-plasticized primary bag. That fact, coupled with Becker's disclosure that the second bag was made of Teflon®, leads to the unmistakable conclusion that the claims at issue were anticipated.

In a district court case on this topic, the court cited Upsher-Smith and In re Baxter Travenol and then found that the reference, though silent, implicitly disclosed the claimed limitation.

Innovatit also argues that it limits its process by requiring that it be conducted "without application of heat," a claim limitation absent from JP '156. ... Here, there is no indication that JP '156 contemplates the addition of heat, and indeed, when the inventor of the Innovatit process himself tried to recreate the results of the process taught in the Japanese reference, he performed his trial at ambient temperature. The Board thus concluded that one skilled in the art would have understood the process in JP '156 to have been carried out at ambient-temperature, and there is substantial evidence to support that factual finding. The negative, ambient-temperature limitation of the Innovatit application thus cannot create patentable novelty.
Innovatit Seafood Systems, LLC v. Commissioner For Patents, 573 F.Supp.2d 96
(D.D.C. Aug 29, 2008) (NO. CIV.A.06-0822 JR, CIV.A.06-0825 JR)

These implicit disclosure cases shows that, in some fact situations, a POSITA would draw an inference that a claimed limitation is disclosed, despite that the fact that the reference is silent about the limitation. However, these cases also show that the explicit teachings must be such that the POSITA can draw inferences to fill in the gap and thus get to the missing limitation.

Related Posts: In a future post, I'll discuss some BPAI cases dealing with silence in a reference. I commented that Applicants need to deal with implicit teachings of a reference in an earlier post here. And today's post was inspired by comments from an Examiner in response to my earlier post about the BPAI decision Ex parte McGrath. That particular Examiner thought the Board's finding in McGrath – the claim limitation of an instruction executable "without interruption" was taught by a reference that failed to mention interruption – was unexceptionable and was based on commonly known case law. [Despite the lack of a case law cite by the Board.] So I researched the issue to be sure I hadn't missing something important. I'm still convinced that the Board considered the right issue in McGrath (what inference would a POSITA would draw from the lack of a discussion in the reference about interruptibility), but reached the wrong result.