52 THE POPULAR SCIENCE MONTHLY 



are affected and hence the germ cells themselves. Certainly such inter- 

 pretations, while the merest speculations, are hard to deny from the 

 known facts. 



In such theoretical discussions of the nature of germ plasm and the 

 potency of factors biologists are very apt to lose sight of the true his- 

 torical purpose of the hypothesis of the inheritance of acquired char- 

 acters. The real question to be answered first is whether or not ac- 

 quired characters actually appear in following generations to such an 

 extent as to make real contributions to the course of evolution. Even 

 if the so-called inheritance is really a change in potency due to the 

 direct action of stimuli on the germ plasm, nevertheless, the Lamarckian 

 factor may be a real factor. "We have not explained away any process by 

 showing the method of its operation. The real question to be decided 

 should be stated broadly. Do new habits and new environment produce 

 changes in form which are of importance in organic evolution ? "While 

 a final answer can not at present be given to the question, it may safely 

 be stated that a renewal of interest in Lamarck's factor is justified by 

 the results of recent research. 



