172 THE SCIENCE OF BIOLOGY 



Granting the existence of such adaptative resemblance, its 

 mode of origin is something to be explained by any com- 

 prehensive theory of the causes of evolution. The Lamarck- 

 ian theory does not seem to give a satisfactory explanation. 

 One cannot easily imagine how an animal by its actions can 

 cause the color or the shape of its body to look like its sur- 

 roundings. It might remain quiet and arrange the parts of 

 its body in certain positions. But to suppose that it can, 

 by use or disuse, make its body look like its background 

 seems absurd. Neither can one imagine how the environ- 

 ment can cause an animal to resemble the background, save 

 in simple cases like that of the caterpillar which is green 

 because the green of the leaves devoured as food shows 

 through its semi-transparent body. The Darwinian theory 

 of natural selection, on the other hand, offers a satisfactory 

 theoretical explanation of how such fitness may have arisen. 

 Against the substantiation of the Lamarckian hypothesis as 

 a whole, there exists, moreover, a body of embryological 

 evidence, obtained during recent years, and supporting the 

 belief that the mechanism of inheritance is through the 

 germ-cells and not through the body. 16 



The most notable supporter of Lamarck, during the early 

 decades of the nineteenth century, was Etienne Geoffroy 

 Saint-Hilaire (1772-1844). St. Hilaire emphasized the ef- 

 fects of the environment, while Lamarck had emphasized use 

 and disuse. The Lamarckian theory, as we speak of it here, 

 includes all of these factors. In 1830, the year following the 

 death of Lamarck, 17 a notable scientific debate took place 

 between Cuvier, who was then regarded as the foremost 

 living zoologist, and St. Hilaire concerning the doctrine of 

 transmutation. The superior acumen and the greater 



18 The volume "Heredity and Environment," by E. G. Conklin, contains an 

 excellent statement of this modern interpretation of the part played by the 

 germ-cells in heredity. 



17 In the later years of his life, Lamarck became blind and lived as a pathetic 

 figure, his theories ridiculed by most of his contemporaries and himself in 

 straightened circumstances. 



