INHERITANCE OF ACQUIRED CHARACTERS 75 



2. The Bearing of this Chapter upon Genetics 



Only those variations which reappear in succeeding 

 generations have to do with heredity. Hence it be- 

 comes important to inquire as to what kind of varia- 

 tions actually reappear. Can variations that are not 

 inborn, but which are acquired during the lifetime of 

 the individual, be inherited ? Does the experience of 

 the parent become a direct part of the child's heritage, 

 or can the environment of the one enter in any way 

 into the heredity of the other ? Can changes wrought 

 in the somatoplasm be so impressed upon the germ- 

 plasm as to change it in such a way that it, in turn, 

 will give rise to similarly modified somatoplasm in the 

 next generation ? Can nurture as well as nature be 

 transmitted ? 



In answering these questions we are of course con- 

 cerned solely with biological inheritance and not at 

 all with those extra-biological accumulations in the 

 way of arts, literature, tradition, invention, and the 

 like which constitute civilization and which make 

 us the "heirs of the ages." Such benefits are entailed 

 upon us much in the same way as property is "in- 

 herited," but they form no part of the personal bio- 

 logical heritage into which we are now inquiring. 



3. The Importance of the Question 



This inquiry concerning the inheritance of acquired 

 characters, which Professor Brooks has called "the 

 interminable question," is not simply an academic 

 matter. Its solution is of vital importance from 



