 This analysis implied for Buffon a significant redefinition of the concept of an organic species, a redefinition that has affected the tradition of natural history and biology since the 1750s. Buffon explicitly rejected the long-accepted meaning of ‘species’ as a universal— or, in modern parlance, a class concept, constituted by a set of individuals on the basis of possession of explicit defining properties . This was the meaning implicit in the Linnaean classification of his time. This concept Buffon criticized as an “abstract” meaning of species. By contrast, Buffon defined a species in natural history exclusively as the historical succession of ancestor and descendant linked by material connection through generation. Such a species is 