S6 THE DOCTRINE OF DESCENT. 



skill that he undoubtedly approached the object at which 

 he aimed — the Natural System. He supplied the first 

 reliable information respecting extinct species. With 

 regard to those v. hich had replaced them in subsequent 

 periods, he was not, as is generally supposed, an un- 

 qualified partizan of new creations, but he refrained 

 from any fixed opinion. " I will not," he says,"* 

 " positively affirm that for the production of tlie present 

 animals a new creation was required. I merely say 

 they did not live in the same locality, and must have 

 come from elsewhere." Geoffroy Saint Hilaire, on the 

 contrary, does not doubt that the animals now living are 

 descended, by an unbroken succession of generations, 

 from the extinct races of the antediluvian age. 



Cuvier's method involved the danger of introducing 

 dogmatism into natural science, and it is therefore 

 justifiable to refer in this place to one of Cuvier's imme- 

 diate disciples only recently deceased — Louis Agassiz, 

 who in the most rigidly ciidactic manner adheres to the 

 systematic categories, and invests them with fine-sound- 

 ing definitions as "embodied creative ideas." '^ Accord- 

 ing to him, species belong to a particular period in the 

 world's history, and bear definite relations to the physical 

 conditions predominant at the time, as well as to the 

 contemporaneous plants and animals. Species are 

 founded on well-defined relations of individuals to one 

 another and the world in which they live, as well as on 

 the proportions and mutual relations of their parts, and 

 on their ornamentation. 



Individuals, as representatives of species, bear the 

 closest relations to one another ; they exhibit definite 

 relations also to the surrounding element, and their 



