346 HEREDITY AND ENVIRONMENT 



of acquired characters is this: Can the differ- 

 ential cause of a character be shifted from the 

 environment to the germ plasm? Can peculi- 

 arities of the environment which influence the 

 development of somatic characters so affect the 

 germ cells that they will produce these so- 

 matic characters in the absence of the peculiar 

 environment? Can the characteristics of a de- 

 veloped organism enter into its germ cells and 

 be born again in the next generation? Con- 

 sidering the fact that germ cells are cells and 

 contain no adult characteristics, it seems very 

 improbable that any peculiarity of environ- 

 ment whether of nutrition, use, disuse or in- 

 jury, which brings about certain peculiarities 

 of developed characters in the adult, could so 

 change the structure of the germ cells as to 

 cause them to produce this same character in 

 subsequent generations in the absence of its 

 extrinsic cause. How, for example, could de- 

 fective nutrition, which leads to the produc- 

 tion of rickets, affect the germ cells, which 

 contain no bones, so as to produce rickets in 

 subsequent generations, although well nour- 

 ished? Or, how could overexertion, leading to 



