AGASSIZ AND EVOLUTION. 23 



they must shed on one another. The two guiding and animating 

 principles of his scientific work were — 1. That the embryonic develop- 

 ment of one of the higher representatives of any group repeated in a 

 general way the terms of the taxonomic series in the same group, and 

 therefore that embryology furnished the key to a true classification ; 

 and, 2. That the succession of forms and structure in geological times 

 in any group is similar to the succession of forms and structure in the 

 development of the individual in the same group, and thus that em- 

 bryology furnishes also the key to geological succession. In other 

 words, during his whole life, Agassiz insisted that the laws of embry- 

 onic development (ontogeny) are also the laws of geological succession 

 (phylogeny). Surely this is the foundation, the only solid foundation, 

 of a true theory of evolution. It is true that Agassiz, holding as he 

 did the doctrine of permanency of specific types, and therefore reject- 

 ing the doctrine of the derivative origin of species, did not admit the 

 causal or natural relation of phylogenic succession to embryonic suc- 

 cession and taxonomic order as we now believe it — it is true that for him 

 the relation between the three series was an intellectual not a physical 

 one — consisted in the preordained plans of the Creator, and not in anj' 

 genetic connection or inherited property ; but evidently the first and 

 greatest step was the discovery of the relation itself, however ac- 

 counted for. The rest was sure to follow. 



But more. Not only did Agassiz establish the essential identity 

 of the geologic and embryonic succe'ssion, the general similarity of 

 the two series, phylogenic and ontogenic, but he also announced and 

 enforced all the formal laws of geologic succession (i. e., of evolution) 

 as we now know them. These, as already stated and illustrated, are 

 the law of diiferentiation, the law of progress of the whole, and the law 

 of cyclical movement, although he did not formulate them in these 

 words. No true inductive evidence of evolution was possible without 

 the knowledge of these laws, and for this knowledge we are mainly 

 indebted to Agassiz. He well knew also that they were the laws of 

 embryonic development and therefore of evolution ; but he avoided 

 the word evolution, as implying the derivative origin of species, and 

 used instead the word development, though it is hard to see in what 

 the words differ. Thus, it is evident that Agassiz laid the whole foun- 

 dation of evolution, solid and broad, but refused to build any scien- 

 tific structure on it ; he refused to recognize the legitimate, the scien- 

 tifically necessary outcome of his own work. Nevertheless, without 

 his work a scientific theory of evolution would have been impossible. 

 Without Agassiz (or his equivalent), there would have been no Darwin. 



There is something to us supremely grand in this refusal of Agas- 

 siz to accept the theory of evolution. The opportunity to become the 

 leader of modern thought, the foremost man of the century, was in his 

 hands, and he refused, because his religious, or, perhaps better, his 

 philosophic intuitions, forbade. To Agassiz, and, indeed, to all men 



