36 
IOWA ACADEMY OP SCIENCES. 
First . — The small, active cell imparts its kinetic energy to 
the large, passive cell, and that energy expresses itself in cell 
division. 
Second . — The large, passive, anabolic cell imparts to the 
daughter cells its anabolic propensities, which express them- 
selves in growth. 
By the growth and division of cells every organism, from 
the hy droid to man himself, attains its perfection. 
It will be seen from what has been said that there is no 
fundamental difference between the reproductive processes in 
the Protozoa and Metazoa. All of the complicated machinery 
associated with sex in the higher forms are merely accessory to 
the fundamental fact of the meeting of two cells, an inter- 
mingling of protoplasm and a subsequent cell division, all of 
which phenomena are essentially present in the conjugation 
and fusion of the Paramecium for instance. 
As to the significance of sex, it is not sufficient to say that it 
serves to perpetuate the species. It does much more. It 
serves to improve species in that the commingling of the char- 
acteristics of two parents furnishes the main potentiality for 
individual variation among the offspring. Indeed, Weismann 
stoutly maintains that we have here the only cause for indi- 
vidual variation upon which natural selection can act, and he 
believes that evolution would be impossible among sexless 
animals. However this may be, it is clearly true that progress 
is much more rapid and certain by virtue of the fact that most 
individuals animals have 2^ father and a mother. 
It would be impossible in the limits of this paper to discuss 
the tremendous ethical, social and moral significance of sex. It 
must suffice to suggest that altruism had its birth in the world 
when brutes first cared for and protected their helpless young, 
and that through the social relations of parent and child, hus- 
band and wife, all that is purest and best in human affairs found 
its inception and its impetus. 
