MODERN BIOLOGY 337 



with the corresponding bones of closely related existing animals. Through 

 this method of reconstruction, which he expounded in his famous work 

 Recbercbes sur les ossemens jossiles (i8ii), Cuvier created the science of palae- 

 ontology in the modern sense. And at the same time he largely reformed 

 the system of zoological classification by introducing fossil animals into it; 

 by account's being taken of the extinct animal forms the investigations into 

 the problem of affinity in the modern animal world have been far more firmly 

 substantiated and placed on a sounder basis than had been possible before, 

 and, moreover, they have led to results that to the systematists of earlier 

 times would have been utterly inconceivable. Of Cuvier's own investigations 

 in this field his comparative study of the order of elephant in particular has 

 won high commendation; he has here shown in the most convincing way 

 what results his new method is capable of giving. He begins by examining 

 the difference between the Indian and the African elephant, which were for- 

 merly grouped as a single species, but which, as he proves by comparison of 

 their teeth and bone-structure, are two widely different species; moreover, 

 he has established the fact that the extinct mammoth, of which he secured 

 as many remains as he possibly could, is in reality more closely related to 

 the Indian elephant than the latter is to the African. And, finally, he com- 

 pares with existing elephants a number of other extinct types, which had 

 either been known before and described by Buffon, or else were in the form 

 of newly-discovered remains; among these fossils there are some from Amer- 

 ica that possess knobby molars, which warrants their being formed into a 

 new genus, Mastodon; the members of this genus must, however, be re- 

 garded as true elephants, for their heavy head postulates a short neck, and 

 this again, as well as the long legs, show that the animal must have pos- 

 sessed a trunk, while from the knobby molars it may be concluded that its 

 food was similar to that of the hippopotamus. Generally speaking, the Pach- 

 ydermata especially interested Cuvier; he studied their existing forms: 

 rhinoceros, hippopotamus, and tapir, in comparison with their extinct an- 

 cestors; of these he described a number of new genera, Pal^eotherium, Dino- 

 therium, etc. Even the small Hyrax he removed, for anatomical reasons, 

 from the rodents, with which it had previously been associated, to the prox- 

 imity of the elephants — one of the most daring applications of his com- 

 parative-anatomical method. The first detailed descriptions of the American 

 giant sloth likewise originate from him. He also carried out some rather 

 sporadic studies of extinct birds and reptiles, which are of considerable value. 



Cuvier as a geologist 

 These investigations into the existence and relationship of extinct animal 

 forms, however, brought Cuvier, as they had formerly brought Buffon, face 

 to face with the question: What changes have taken place in the character 

 of the earth's surface that have caused the dissimilarity between the animal 



