352 BIOLOGY 



assumed that diversities produced in individuals as the result 

 of the action of the environment, or of their own habits, i. e., 

 acquired variations, are transmitted to subsequent generations, 

 and serve as the basis of the changes which produce race varia- 

 tions and evolution. Our study of heredity has shown that such 

 variations, according to our present knowledge, are almost 

 certainly not transmitted to subsequent generations. It is 

 evident that the very foundation of the Lamarckian theory can- 

 not stand, if the modern conception of heredity is accepted. 



Lamarck's views were not accepted in his day. This was 

 partly because the great French naturalist, Cuvier, one of the 

 greatest naturalists that ever lived, opposed them strongly; 

 and partly because the scientific world was not at that time 

 ready to accept any such natural explanation of the origin of 

 organisms as that suggested by Lamarck. They were, therefore, 

 practically forgotten for a period of fifty years, during which 

 time the idea that organisms had appeared by the process of 

 descent had practically no followers, special creation of each 

 species to fit its environment being the generally accepted 

 view. A new era of thought was inaugurated in the middle of 

 the nineteenth century by Chalmers, Spencer, and especially 

 in 1859, by Charles Darwin. 



Charles Darwin. Charles Darwin was the grandson of 

 Erasmus Darwin, already mentioned. In 1859 he published a 

 book, the result of twenty years' work, entitled "The Origin 

 of Species," which produced a revolution in thought, not only 

 in science but also in philosophy. Darwin accepted the idea of 

 the origin of modern organisms from earlier ones by a process 

 of direct descent, recognizing that divergence of type from com- 

 mon centers has been the law of historical development of ani- 

 mals and plants. To this extent, therefore, Darwin followed 

 Lamarck and the early speculators concerning the origin of 

 animals. Darwin's method of explaining this descent was 

 totally different from that of Lamarck, and much more in ac- 

 cordance with facts that could be demonstrated. According to 



