ABSTRACT
No history of the biological sciences in the eighteenth century can be adequate which fails to keep in view the fact that, for most men of science throughout that period. The theorems implicit in the conception of the Chain of Being continued to constitute essential presuppositions in the framing of scientific hypotheses. The theory of the Chain of Being, purely speculative and traditional though it was, had upon natural history in this period an effect somewhat similar to that which the table of the elements and their atomic weights has had upon chemical research in the past half-century. In spite of the violent reaction of the astronomy, physics, and metaphysics of the Renaissance against the Aristotelian influence, in biology the doctrine of natural species continued to be potent. The more one increases the number of one's divisions, in the case of the products of nature, the nearer one comes to the truth; since in reality individuals alone exist in nature.
