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VI EVOLUTION IN BIOLOGY 195 
_ 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 
- getting people to use their own powers of investiga- 
tion 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 Casper Friederich 
Wolff, who in his “'Theoria Generationis,” pub- 
lished 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 embryo- 
- logists ; and it was only in the course of the first 
thirty years of the present century, that Prévost 
and Dumas in France, and, later on, Dollinger, 
Pander, Von Bir, Rathke, and Remak in Germany, 
founded modern embryology; while, at the same 
time, they proved the utter. incompatibility of the 
hypothesis of evolution, as formulated by Bonnet 
and Haller, with easily demonstrable facts. 
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