1 6 THE POPULAR SCIENCE MONTHLY 



impression that he supposes the determinants of the chromosomes to 

 pass out into the cell, multiply there, and become the differentiated part. 

 Perhaps this is only due to his attempt to visualize his conception, and 

 he might grant that the differentiation of the determinants may depend 

 on the interaction of many parts of the cell. But if we take his view 

 literally to mean that the determinants are the materials out of which 

 specific structures are directly built up, then his conception of the 

 nature of a determinant is widely different from my own concerning the 

 relation of "factors" and body characters. 



