 The encounter with a wide body of new data from the colonies and exploratory voyages returned to Paris during the course of the writing of the Natural History impressed Buffon with the degree to which species seemed to be affected by external circumstances such that from a single source numerous “degenerations” could arise in some groups. This formed the conceptual basis for his concept of a race as distinguished from a Linnaean Variety. A “race” in the Buffonian sense was a historical degeneration from a common ancestor that maintained material and historical connection to this common source form. But this lineage could undergo substantial and quasi-permanent hereditary differentiation into different lineages, with the cause of these degenerations explained by slight changes in the organic molecules produced by varying environmental circumstances as a given physical species migrates to new environments. These slight changes in turn affected the internal mold. Developed in greatest detail in his long article, “On the Degeneration of Animals” in volume XIV (1766) of the Natural History, Buffon’s theory of the degeneration of species extended so far as to allow the lumping of the quadrupeds of both the Old and New worlds into a limited number of primary “families” (familles) and “genera” (genres) that from points of origin in the Northern European hemisphere, degenerated in time in response to migration to new locales. By including human beings in this naturalistic scenario in his later writings, and assuming that human lineages underwent similar degenerative changes as they migrated from their postulated point of origin of human beings in the Caucasus, Buffon’s theory played a major role in the development of Enlightenment racial theory (Sloan 1973, 2014).