MENDELISM AND OTHER METHODS OF DESCENT 227 



descent of the species. In neither series was there any primary 

 or essential difference between the cells as body-cells or as 

 germ-cells, but vegetative specialization has repeatedly, and in 

 many independent groups, rendered a part of the cells sterile 

 neuters whose function it is to nourish and protect the repro- 

 ductive cells and the helpless offspring, instead of leaving any 

 direct progen}- of their own. Organisms are, after all, merely 

 social organizations of cells, and there are different kinds of 

 cell-organizations, just as there are different kinds of organiza- 

 tions among men and other social animals. 



Generally speaking, the cells which compose the bodies of the 

 higher organisms do not leave any descendants to perpetuate 

 their characters. Except for the fact that the body-cells and 

 the sex-cells are both descendants of the original gametes, there 

 is no relation between them, just as the highly specialized castes 

 of ants and termites are sterile, and are propagated anew in each 

 generation from normal sexual insects, and not from any ances- 

 tors which possessed these specialized caste characters. Thus 

 if the character-unit theory were to be logically elaborated the 

 germ-cells would need to be thought of as containing, not merely 

 * units to represent the formal characters in which species and 

 varieties differ, but units governing the characters and adjust- 

 ments of every separate cell of the vegetative body. All the 

 different kinds of cells which compose the body of a higher 

 plant or animal represent as many cell castes, and there would 

 need to be character-unit determinants to govern the formation 

 and arrangement of these, quite as much as for the different 

 kinds of organisms which the species may contain. 



The germ-cells continue to transmit characters which can be 

 brought into expression only through the medium of vegetative 

 cells which do not take any part in the reproductive process, 

 any more than soldiers, workers and nurses of a colony of ants 

 or termites. The complexities of this problem of transmission 

 transcend the powers of the human imagination, but there do 

 appear to be any corresponding limitations in practice, for even 

 characters which are not expressed may still be carried along, 

 generation after generation. The greater the number of details 

 the more effective and reliable is this hereditary memory, if 



