XL] EVOLUTION IN BIOLOGY. 281 



and is thus the equivalent of Bonnet's germ, 1 as 

 defined in the passage cited above. But Buffon 

 further imagined that innumerable " molecules organ - 

 iques " are dispersed throughout the world, and that 

 alimentation consists in the appropriation by the 

 parts of an organism of those molecules which are 

 analogous to them. Growth, therefore, was, on this 

 hypothesis, a process partly of simple evolution, and 

 partly of what has been termed " syngenesis." Buffon's 

 opinion is, in fact, a sort of combination of views, 

 essentially similar to those of Bonnet, with others, 

 somewhat similar to those of the "Medici" whom 

 Harvey condemns. The " molecules organiques " are 

 physical equivalents of Leibnitz's " monads." 



It is a striking example of the difficulty of get- 

 ting people to use their own powers of investigation 

 accurately, that this form of the doctrine of evolution 

 should have held its ground so long; for it was 

 thoroughly and completely exploded, not long after 

 its enunciation, by Caspar Friederich Wolff, who in 

 his "Theoria Generations, " published in 1759, placed 

 the opposite theory of epigenesis upon the secure 

 foundation of fact, from which it has never been 

 displaced. But Wolff had no immediate successors. 

 The school of Cuvier was lamentably deficient in 

 embryologists ; and it was only in the course of the 

 first thirty years of the present century, that Prevost 

 and Dumas in France, and, later on, Dollinger, 

 Pander, Von Bar, Kathke, and Remak in Germany, 

 founded modern embryology ; while, at the same time, 



1 See particularly Buffon, l.o. p. 41. 



