178 Heredity and Environment 



II. CORRELATIONS BETWEEN GERMINAL AND SOMATIC 

 ORGANIZATION 



All the world knows that the organization of the germ is not 

 the same as that of the developed animal which comes from it, and 

 yet the specificity of the germ indicates that there must be some 

 correlation between the germinal and the developed organization ; 

 in short, there is not identity of organization but correlation of 

 organization between the germ and the adult. What correlations 

 are known to exist between the oosperm and the developed ani- 

 mal? 



Inheritance Factors and Developed Characters. We have con- 

 sidered in the preceding chapter (pp. 100-105) the evidence that 

 there are specific inheritance factors or genes which are correlated 

 with the development of specific adult characters. These factors 

 are not the characters in miniature nor are they the "representa- 

 tives" or "carriers" of characters, but they are the differential 

 causes of characters. Every inherited character must have a 

 differential cause in the germ cells, but this cause may not be a 

 peculiar vital corpuscle nor even a peculiar atom or molecule but 

 it must at least be some particular combination of atoms or mole- 

 cules. It is practically certain that this differential cause of each 

 inherited character is associated with some material substance 

 which occupies some place in the germ cells. 



Location of Inheritance Factors. If it is asked whether there 

 are particular structures in germ cells which correspond to par- 

 ticular inheritance factors it must be admitted that we have no 

 certain knowledge on this subject and that opinions differ greatly 

 with respect to it. On the one hand it is maintained that the 

 entire germ is concerned in the development of every character, 

 and on the other hand that the differential cause of any character 

 may be located in some differentiated structure or function of the 

 germ. These views are not mutually exclusive and it may well 

 be that both are true. We know that germ cells are composed of 



