Distribution by Sex 361 



cells and founding new associations, the former can only 

 continue the growth for which they are specialized. Such a 

 dififerentiation also proceeds in other ways. Suppose an- 

 other case. Before any subordinate cell arises, there occur 

 several divisions of the prime cell, producing equally quali- 

 fied cells, eight, or sixteen or thirty-two in number, all of 

 which remain associated; and then and not till then the 

 somatic subdivision begins and some of these cells produce 

 attendant cells of the only partly qualified type. This process 

 is observed in nature ; that is to say actual living germ cells 

 can be seen to divide in this manner. Several species form 

 thus the bunch of cells called a "morula," any one of which 

 is capable for a time of being promoted to the functions of 

 separate life and if favored by environment can become a 

 separate complete individual. But in normal development 

 one of the early cells, the ninth or the seventeenth, or what- 

 ever the habit may demand, shows a lesser endowment and 

 instead of taking equal and symmetrical place with the 

 others, begins the formation of a new substance of lesser 

 degree. 



Meantime all the cells continue to divide, and in due 

 course nearly all are appointed, in the same way, to special 

 duties and lesser dignity. There is, however, one line in 

 which, by direct succession and division, the original, fully 

 endowed, germ-plasm is continued. This line of cells divides 

 always in the germ fashion, that is by full Karyokinesis, 

 until maturity, and then at last it divides as we remarked 

 in the evolution of sex and a sex cell appears. The germ- 

 plasm is a mass of protoplasm growing in line direct, sur- 

 rounding itself with descendants specially limited to sub- 



