Funk Brothers Seed v. Kalo: When a Mixture of Natural Bacteria Is Not Patentable

Funk Brothers Seed Co. v. Kalo Inoculant Co., 333 U.S. 127 (1948), is a foundational statement of the rule that a product of nature — and the discovery of a natural phenomenon — cannot be patented merely by packaging it. Writing for the Court, Justice Douglas held that a mixed culture of several naturally occurring strains of nitrogen-fixing Rhizobium bacteria, selected because they do not inhibit one another, was not patentable subject matter. The bacteria’s qualities were “the work of nature,” free to all and reserved to none, and combining strains that nature had already equipped to coexist was “hardly more than an advance in the packaging of the inoculants.” Decided decades before the biotechnology era, Funk Brothers framed the analysis the Supreme Court would later use in Chakrabarty, Mayo, and Myriad, and it supplied the intellectual seed of today’s “inventive concept” requirement under 35 U.S.C. § 101.

At a glance

• Case: Funk Brothers Seed Co. v. Kalo Inoculant Co., 333 U.S. 127 (1948)
• Court: Supreme Court of the United States, on certiorari to the U.S. Court of Appeals for the Seventh Circuit
• Decided: February 16, 1948; 7–2
• Opinion: Justice Douglas, for the Court; Justice Frankfurter concurring; Justice Burton dissenting (joined by Justice Jackson)
• Subject matter: Product claims to an inoculant comprising a mixture of mutually non-inhibitive strains of leguminous Rhizobium bacteria
• Holding: Claims to a mixture of naturally occurring bacterial strains, each performing as it does in nature, are not patentable because they claim a product and phenomenon of nature rather than an invention

The invention and the claims

Leguminous plants — clover, alfalfa, soybeans, and the like — fix atmospheric nitrogen through Rhizobium bacteria that colonize their roots. Farmers had long inoculated seed with these bacteria to boost yields. The practical problem was specificity: each species of Rhizobium infects only a particular cross-inoculation group of plants, and, as understood before the patent, different species tended to inhibit one another when mixed in a single culture. Manufacturers therefore packaged and sold a separate inoculant for each group of legumes.

The patentee, Bond, discovered that certain strains of the several Rhizobium species do not exert this mutually inhibitory effect and can be combined in one culture without either strain losing its efficacy. That discovery permitted a single, mixed inoculant capable of serving several groups of legumes at once. The patent claimed both a method of producing the multi-purpose inoculant and the inoculant product itself. Only the product claims were before the Supreme Court. The District Court had upheld the claims, but the Seventh Circuit held the product claims invalid, and the Supreme Court affirmed that judgment of invalidity.

The qualities of the bacteria are the work of nature

Justice Douglas’s opinion turns on a single distinction: between discovering a fact about nature and inventing something new. The Court accepted that Bond’s discovery — that particular strains are mutually non-inhibitive — was genuine and useful. But it located that discovery entirely within the natural world. “The qualities of these bacteria, like the heat of the sun, electricity, or the qualities of metals, are part of the storehouse of knowledge of all men,” Douglas wrote. “They are manifestations of laws of nature, free to all men and reserved exclusively to none.” Because “patents cannot issue for the discovery of the phenomena of nature,” the non-inhibitive quality that made the mixture possible could not itself support a patent.

That left the question whether the application of the discovery — assembling the strains into one product — supplied the required invention. The Court held it did not. Each species, once combined, “has the same effect it always had”; the strains “serve the ends nature originally provided and act quite independently of any effort of the patentee.” No strain acquired a new property, a new use, or an enlarged range of utility from being mixed with the others. As Douglas put it, the aggregation “is an application of th[e] newly discovered natural principle,” but “however ingenious the discovery of that natural principle may have been, the application of it is hardly more than an advance in the packaging of the inoculants.” The combination was “no more than the discovery of some of the handiwork of nature and hence is not patentable.”

Frankfurter’s narrower path and the “product of nature” line

Justice Frankfurter concurred in the result but resisted the majority’s sweeping “laws of nature” reasoning. He worried that phrases like “the work of nature” and “the laws of nature” were “too vague and malleable” to serve as a test, and that they risked confusing the distinct requirements of the patent law. He would have invalidated the claims on a narrower, more concrete ground: the patent failed to define the invention with the particularity the law demands. The specification described the useful strains only by the functional property of non-inhibition, without identifying them with enough specificity that a competitor could know what was claimed and what remained free. For Frankfurter, the vice was indefiniteness in claiming a result rather than a described thing — a concern that echoes the enablement and definiteness doctrines and that anticipates later debates about functional claiming.

The two opinions together mark the enduring difficulty of the “product of nature” doctrine: everything a chemist or biologist works with is, at some level, drawn from nature, so the line cannot be that natural ingredients are involved. The majority’s answer was that patentability requires giving the natural material some new, non-natural utility or characteristic — a requirement the mixed inoculant did not satisfy because the bacteria did exactly what they do in the wild.

Open questions

Funk Brothers announced a principle without a bright-line rule, and later cases had to police its boundary. In Diamond v. Chakrabarty, 447 U.S. 303 (1980), the Court upheld a patent on a live, genetically engineered bacterium precisely because the organism was “a nonnaturally occurring manufacture” with “markedly different characteristics from any found in nature” — the very quality the Funk Brothers mixture lacked. In Association for Molecular Pathology v. Myriad Genetics, 569 U.S. 576 (2013), the Court invoked the same distinction to hold that isolated genomic DNA was an unpatentable product of nature while a synthetic cDNA molecule was eligible. And in Mayo Collaborative Services v. Prometheus Laboratories, 566 U.S. 66 (2012), the Court leaned on Funk Brothers to insist that a patent applying a natural correlation must add an “inventive concept” beyond the natural principle itself. The open question Funk Brothers bequeathed — how much human intervention transforms a product of nature into an invention — remains contested in every generation of biotechnology and diagnostics litigation.

Implications

• Discovering a natural fact is not inventing. Identifying a previously unknown property of a natural material, however valuable, does not by itself yield patentable subject matter; the claim must capture something new that nature did not already provide.
• “Packaging” natural components rarely suffices. Combining or aggregating naturally occurring things that each keep their natural function is vulnerable under Funk Brothers; look for a new utility, structure, or characteristic that the combination creates.
• Draft to a changed thing, not a natural quality. Frankfurter’s concurrence is a warning against claiming a result or a natural property in functional terms; describe the specific, altered composition and what makes it non-natural.
• The doctrinal through-line runs to § 101 today. Funk Brothers is the ancestor of the Mayo/Alice “inventive concept,” and it still governs how courts and the USPTO evaluate claims to isolated biological materials, mixtures, and natural-product applications.

Frequently asked questions

What did Funk Brothers hold? That product claims to a mixed culture of several naturally occurring, mutually non-inhibitive strains of Rhizobium bacteria were not patentable, because the strains’ non-inhibitive qualities were the work of nature and combining them added no invention beyond that discovery.

Why was the bacterial mixture treated as a “product of nature”? The Court found that each strain in the package performed exactly as it does in nature; the patentee did not alter the bacteria or give them new properties. The discovery that certain strains do not inhibit one another was a discovery of a natural quality, and the packaging of them together was, in the Court’s words, “hardly more than an advance in the packaging of the inoculants.”

How does Funk Brothers connect to modern eligibility law? It is a direct ancestor of the “inventive concept” requirement. The Supreme Court relied on Funk Brothers in Mayo v. Prometheus (2012) and distinguished it in Diamond v. Chakrabarty (1980) and Association for Molecular Pathology v. Myriad Genetics (2013) when drawing the line between unpatentable natural phenomena and patentable human-made applications.

Authorities and sources

• Funk Brothers Seed Co. v. Kalo Inoculant Co., 333 U.S. 127 (1948) (decided February 16, 1948). Justia; Cornell Legal Information Institute.
• Case summary and vote via Oyez.
• Douglas authorship, 7–2 vote, Frankfurter concurrence, and Burton dissent (joined by Jackson) corroborated by Wikipedia: Funk Bros. Seed Co. v. Kalo Inoculant Co..
• Later treatment of the product-of-nature line: Diamond v. Chakrabarty, 447 U.S. 303 (1980); Association for Molecular Pathology v. Myriad Genetics, 569 U.S. 576 (2013).