THE GROWTH AND SCOPE OF BIOLOGY 



17 



eighteenth century, betrayed a sUght loaning to t,he possibihty of evohi- 

 tion in his later writings when he conceived that the species belonging to 

 the same genus might have had a common origin. His contemporary, 

 I3utfon, speculated more openly upon the origin of the various life forms 

 and was unwilling to accept the notion of independent creations. It was 

 not until the time of Lamarck (Fig. 12), however, that any general theory 

 of evolution was proposed. Lamarck observed the great variation exhil/- 

 ited by animals and conceived that it was due to the effects of use or disuse 

 of the various organs by the animals. He supposed that the changes thus 

 induced were inherited, thus becoming permanent — a view that has been 



Fig. 13. — Charles Darwin, 1809-1882. (From University Magazine. 



Leonard Darwin.) 



Photograph by 



abandoned by most biologists since then. These views of Lamarck were 

 expressed most fully about 1809, at the beginning of what may be 

 regarded as the modern period in biology. As has been pointed out in an 

 earlier section, Cuvier opposed the evolution doctrine, notably in the 

 series of discussions in the French Academy of Science in 1830, and his 

 great personal influence determined the attitude of French biologists 

 toward the new doctrine. 



It was in another land, therefore, that the chief modern development 

 of the evolution idea had its origin. To Charles Darwin (1809-1882) 

 (Fig. 13), of England, is due the credit of convincing the thinking world 

 that change of species has taken place throughout the whole history of 

 living things. This he did partly by marshalling such a mass of evidence 

 in favor of evolution that there was no rejecting it, partly by devising a 



