Nevertheless, when Darwin first revealed the theory of pangenesis to his friend Thomas Huxley, Huxley told him to re-read Buffon's ideas.  The effect was sobering to Darwin, as he wrote back to Huxley, "I have read Buffon: whole pages are laughably like mine.  It is surprising how candid it makes one to see one's view in another man's words."

Though Buffon's theory was inaccurate, it must be appreciated in light of its 18th century intellectual milieu. The phenomenon of heredity and that of the regrowth of body parts had not been clearly delineated; this can be seen in our term "generation" for one and "regeneration" for the other. In the mid-1700's the term "reproduction" was used exclusively what we now know as regeneration, as in planaria, starfish, and polyps. It appears to have been Buffon who first saw the relationship between regeneration and heredity, and appreciated that they were related phenomena.  A theory of heredity would have to account for both. He therefore began to use "generation" to mean reproduction (as sexual conjugation), regeneration (as regrowth of lost body parts), and fission (as asexual reproduction).  It is of course the cell theory, derived over the course of the next century and a half in Germany, which provides the ultimate synthesis of these phenomena, united by Buffon.

His speculations on the nature of species were part of a broader attempt to bring the natural world under one grand theoretical umbrella.  Buffon postulated the existence of two factors critical to the growing embryo: a fuel for the developing mass, and a blueprint to guide its differentiation.  The fuel, he considered, was a constant store of "organic molecules" which the embryo is able to ingest, and which have the power to recombine (via an "attractive force") into the form of the developing organ.  The blueprint for this development was an "internal mold" into which the embryo was cast. Buffon attempted to model his system on Newtonian mechanics, the attractive force between organic molecules paralleling the force of gravity between masses.

Organic molecules, to Buffon, are present in all living organisms. When consumed, they are transformed and utilized by the consumer.  These processes are guided by the internal mold during the development of the organism.  Once it has reached sexual maturity and has ceased to grow, its organs become saturated with organic molecules, and any additional molecules are simply sloughed off by the respective organs and shunted into the reproductive system.

Even in Buffon's own time the internal mold and its attenuating constructs did not become widely accepted, and today it looks to us absurdly primitive.  Nevertheless, we may get a glimpse into Buffon's foresight if we reach into our modern lexicon and substitute "genome" for "internal mold" and "protein" for "organic molecule."  The function of the genome is to cast the organism in the likeness of the species, and it accomplishes this end by directing the synthesis of species specific proteins from amino acids. Free amino acids, of course, are the anabolic products of the organism's ingested, then digested, protein.

Obviously Buffon knew none of this. But he recognized the existence of an internal agent directing the growth and development of the organism, and keeping it within the confines of the species. He recognized that the transformation of nutrients into highly specific somatic growth was the result of such a directing agent, and he located it (again following Newton's lead) within the realm of the knowable. His theory accounted for the resemblances within species and within (literal, not taxonomic) families; as well as for the possibility of altering the form of a species by placing it in a new environment with different food sources and consequently a different set of "organic molecules."

This last idea, though thoroughly fallacious by modern standards, is significant insofar as it afforded Buffon a mechanism whereby races of organisms could be transformed (or "degenerated").  Buffon, of course, meant transformation within the limits set by the internal mold, which in practice meant within the limits of hybridization -- within the species. Nevertheless he emerged with the first cogent theory of microevolution, which were derived from his theories of heredity and development.

One of the reasons Buffon was willing to accomodate biological change in his theories was that he recognized major geological change in the earth's history, and appreciated the synergism which must exist between geological and biological histories of the earth. In fact, the great bulk of Buffon's biological works in Natural History were sandwiched between two major speculative essays on geology: Theory of the Earth (Vol. I, 1749) and Epochs of Nature (Suppl. Vol. V, 1778).

Buffon's consideration of evolution over a century before Darwin has been the source of much contention, beginning with Samuel Butler's Evolution, Old and New (1879). Butler, an anti-selectionist, which is to say, an anti Darwinian but a confirmed evolutionist nonetheless, sought to devalue Darwin's contribution by suggesting that Buffon had formulated the general principles of evolution a century in advance of Darwin. Butler was faced with what might seem a difficulty: that Buffon can never be found to advocate trans-specific evolutionism; he proposes it occasionally, and invariably goes on to reject it.

Butler used a somewhat tortured logic to argue that Buffon's rejection of macroevolution was only presented tongue-in-cheek.  But Buffon's objections to trans-specific evolution are numerous and profound, at least in the context of 18th century biology.  More importantly, however, Buffon treated the question of evolution as a subset of a greater problem: that of the reality of higher taxonomic categories, to which he is consistently and unequivocally opposed for the great bulk of his career.

Buffon railed particularly against the taxonomy of his great contemporary Linnaeus, who was organizing living species into a set of nested categories of equal rank.  Buffon denied the existence of higher categories, working solely within the framework of the Great Chain of Being.  Indeed, he felt a direct implication of the Linnaean classification to be the inference that all the species in one family were descended from a common ancestor -- a belief he rejected with scorn, along with the Linnaean system. The irony, of course, is that Buffon attributes evolutionary ideas to to the least evolutionary of 18th century workers; insofar as Linnaeus consistently maintained that there had been no new species formed since the creation. Buffon himself thought far more about evolution than did Linnaeus.
 

"The misunderstanding between these two able Naturalists is most injurious to science," wrote Thomas Pennant in 1771, "The French Philosopher scarce mentions the Suede, but to treat him with contempt; Linnaeus in return, never deigns even to quote M. de Buffon, notwithstanding he must know what ample lights he might have drawn from him."

In Buffon's hands, the concept of species also underwent a dramatic metamorphosis. Unlike the typological Linnaean species, what marks a Buffonian species is that they form a historical stream of reproductive compatibility (Farber, 1972).  Thus, in his 1753 article on the donkey (Vol. IV), Buffon writes:
 

     All the similar individuals existing upon the surface of the earth are regarded as composing the species of these individuals. Yet it is neither the number nor the collectivity of similar individuals, but the constant succession and renewal of these individuals which constitute the species. The species is therefore an abstract and general form, which can only be understood by considering nature through the succession of time, and in the constant destruction and renewal of beings.
     The species is thus only a constant succession of individuals able to reproduce  together.