Neilson v. Harford: Shape and Form in Patent Law

Forthcoming, Research Handbook on Creativity, Entrepreneurship, and Intellectual Property: Comparative Perspectives on Forgotten Legal Lore

UC Hastings Research Paper No. 393

35 Pages Posted: 22 Jan 2020 Last revised: 7 Aug 2020

See all articles by Jeffrey A. Lefstin

Jeffrey A. Lefstin

University of California Hastings College of the Law

Date Written: January 9, 2020

Abstract

Neilson v. Harford has cast a long shadow over patent law. For American courts in the nineteenth century, the 1841 case from the Court of Exchequer was an authority whose “correctness has never been doubted and denied.” More recently, Neilson served as the ostensible authority for some of the Supreme Court’s most significant changes to the doctrine of patent eligibility under § 101. Parker v. Flook took from Neilson the notion that fundamental principles cannot contribute to the patent-eligibility of a claim, and Mayo v. Prometheus relied on Neilson to support its requirement for unconventional application of new discoveries.

Drawing on a complete account of the Neilson trial that has never been examined by legal scholars, this chapter shows that the true story of Neilson v. Harford is very different than the one told by the Supreme Court. The Court of Exchequer never treated fundamental principles as part of the prior art, nor did it require inventive application of new discoveries; Neilson’s patent was sustained largely because discovery required only well-known, routine, and conventional means for application. The central question in Neilson was to what extent Neilson’s invention – and by extension patents in general – were bound by shape and form.

The Exchequer’s conclusion that Neilson’s patent transcended form was key to three of the Supreme Court’s foundational nineteenth century cases: Winans v. Denmead’s extension of infringement beyond the patentee’s embodiment; Tilghman v. Proctor’s separation of a process from its instrumentalities; and O’Reilly v. Morse’s delineation of the outer bounds of enablement. In particular, the Morse Court’s contrast between Neilson’s invention and Morse’s illustrates that Morse was based on conventional enablement reasoning, not on the unpatentability of scientific discoveries.

Keywords: patent law, patent eligibility, Neilson v. Harford, hot blast

JEL Classification: O34

Suggested Citation

Lefstin, Jeffrey A., Neilson v. Harford: Shape and Form in Patent Law (January 9, 2020). Forthcoming, Research Handbook on Creativity, Entrepreneurship, and Intellectual Property: Comparative Perspectives on Forgotten Legal Lore, UC Hastings Research Paper No. 393, Available at SSRN: https://ssrn.com/abstract=3516370 or http://dx.doi.org/10.2139/ssrn.3516370

Jeffrey A. Lefstin (Contact Author)

University of California Hastings College of the Law ( email )

200 McAllister Street
San Francisco, CA 94102
United States

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