THE WOMAN OF EVOLUTION AND PESSIMISM. 



313 



acters of their descendants. To have two parents in- 

 stead of one is to widen the range of possible variation. 

 With time this identity of the two elements in pa- 

 rentage disappears. It gives way to specialization, re- 

 sulting in a division of function between 

 Specialization tfae twQ sexeg and tfae distinction of 

 of germ cells. 



germ cells from other cells. The germ 



cell in the higher creatures gains characters and quali- 

 ties of its own not possessed by the other cells of the 

 body. As the character of double parentage is retained 

 in the development of the higher animals and plants, it 

 too is specialized and perfected. " Nature," says Weis- 

 mann, " has no better way of encouraging variation than 

 by preventing individual units from developing alone." 



In the germ cell of the female, known as the egg or 

 ovum, food yolk is deposited for the use of the young 

 organism. This burden reduces the activity of the fe- 

 male cell. It becomes sessile and motionless. Its cog- 

 nate, the male germ, on the other hand, is specialized 

 to seek the egg cell. It is made up of an almost bare 

 nucleus to which is attached a vibratile structure which 

 gives it the power to move. 



This differentiation of sex in the germ cell produces 

 changes and reactions in the organism from which it 

 proceeds. The egg-bearing sex becomes in comparison 

 with the other sessile, expectant, conservative. The 

 feeding of the young and its protection from external 

 enemies falls to the lot of the female. The male be- 

 comes in varying degree the food winner, the fighter, 

 the one which struggles against outside foes. Greater 

 physical strength is co-ordinated with the need for 

 greater activity. Increased force demands increase of 

 size of body. Increased muscular development necessi- 

 tates increase in size of the sensorium or brain which 

 controls it. 



