WHAT IS PHYSICAL LIFE 



matin rods in the nucleus, he falls foul of 

 an equally eminent biologist, Oscar Hert- 

 wig, who complains that Weismann leads 

 us into an invisible world, in which there 

 is no foothold for research, and with no 

 foundation of fact. 



This is only a sample of the interchange 

 of personal compliments which has been 

 going on between different authorities in 

 biology for the last twenty years. The only 

 agreement is that every one believes in evo- 

 lution, but as to the process of evolution 

 there is an all-round disagreement, with no 

 prospect of a satisfactory substitute for 

 the Darwinian theory in sight. 



The only alternative theories which have 

 attracted much notice are the once cele- 

 brated Lamarckian theory, and the more 

 modern theory of Orthogenesis. La- 

 marckianism, in distinction from the nat- 

 ural selection of Darwinism, has Use and 

 Disuse for its principle. By constant use 



