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 
the two sexes and the distinction of 
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. 
Specialization 
of germ cells. 
