Natural history, law, and the politics of redefinition in the Age of Reform

William Sharp Macleay (1792–1865) is best known for his invention of the strange and elaborate “quinarian” system of biological classification, which gained enormous popularity in Britain almost immediately after its initial explication in 1819. While the curious story of “quinarianism” is already a somewhat obscure episode in nineteenth-century natural history, even less is known about Macleay’s decade-long participation, beginning in 1825, in the de facto abolition of the Atlantic slave trade around Cuba. While an 1817 treaty had formally outlawed the purchase and sale of enslaved peoples in the region, the trade continued in practice well beyond that point. From his colonial post in Havana, Macleay occupied leading positions in the mixed admiralty court tasked with adjudicating the cases of ships captured on suspicion of engaging in it. This article first recovers Macleay’s views on human difference, what we might call a “quinarian anthropology.” It then details his work on the mixed commission at Havana between 1825 and 1836, where he continually struggled to stamp out the smuggling of enslaved peoples against a Spanish conspiracy to surreptitiously support it. Finally, it reads Macleay’s work in law and natural history collectively, lashed together by the unifying concept of redefinition. Macleay, it argues, pursued his efforts to reform the order of nature in tandem with his efforts to reform the language and interpretation of the laws that bound his rulings. In both cases, that work of reform relied on altering definitions, creating new terms, and recruiting allies to adopt and advance them.