Where a disclosure describes the exclusion of a broad genus, claims to embodiments which exclude particular species are only supported if the disclosure offers some guidance or “blaze marks” to guide the skilled artisan towards excluding that particular species. Moreover, if the disclosure requires the exclusion of a particular species, it cannot be said to support the sole exclusion of other species.

Background / Facts: The application on appeal here from rejection at the PTO is for preventing the onset of bovine mastitis, i.e., the inflammation of udder tissue in cows. In this regard, the application provides a composition that employs a physical barrier within the teat canal to block the introduction of mastitis-causing organisms without requiring the use of antiinfectives such as antibiotics. During reexamination, the applicant sought to introduce the limitation that the teat seal canal had “an acriflavine-free” formulation. Acriflavine was a well-known antiseptic antiinfective agent which had long been used to treat mastitis, but was not mentioned anywhere in the original disclosure.

Issue(s): Whether the disclosure demonstrates possession under § 112, ¶ 1 of a specifically acriflavine-free composition.

Holding(s): No. The full scope of the claimed teat seal canal having “an acriflavine-free” formulation encompasses formulations that exclude acriflavine but could include antibiotics. Yet, the application is directed to a “non-antibiotic approach” to preventing mastitis, and explains how this approach achieves the benefit of “meeting consumer preferences for reducing the levels of antibiotics used in food production.” Several other examples are cited where, although the formulation “does not expressly exclude any particular class of antiinfective, one nevertheless comes away with the clear understanding that it cannot include antibiotics compositions.” The court concluded that “[t]he specification thus leaves no room for argument that the inventor possessed a formulation that excludes only acriflavine while permitting the use of antibiotics.” The disclosure is “therefore inconsistent with a claim which excludes acriflavine, but not the presence of other anti-infectives or antibiotics,” and hence, properly rejected for lack of written description under § 112, ¶ 1.

Full Opinion