Origin of Sex. 309 



cell will be driven with more impetuosity than the other and will there- 

 fore appear the more active of the two. In the mild currents and ten- 

 sions which rule in vital activities, the difference between the two is 

 small, but no doubt is real and persistent, and therefore efficient and 

 certain. Thus we first trace all the secondary characteristic differentia- 

 tions of sex back to the difference in activity of the primary elements, 

 the first sexual cells. And next, with reasonable certainty, we discover 

 this difference in activity to be based on a fundamental difference in the 

 motions of ether the most elementary form of matter. 



Reproduction is a species of growth. There are different directions 

 in which an individual may grow, depending upon the part of him to- 

 ward which the stream of nutritive fluid is directed, a matter which de- 

 pends upon the habit of his activities. If his brain, his muscles and 

 his viscera each receive their due share, they will in time reach an ap- 

 proximate limit of growth and receive a check, in which case a portion 

 of the nourishment is diverted toward reproduction, or the setting up of 

 a new individual. A circumstance which diverts nourishment from the 

 general body of the organism will tend to concentrate it upon the repro- 

 ductive organs. What is remarkable is that when the total amount of 

 the nourishment is great it is monopolized by the general body or the 

 most active part of it, but if the total amount is suddenly reduced, an 

 adequate portion, or at least a greater proportion, is diverted to the re- 

 productive function ; as if nature were satisfied to allow the present 

 generation to live as long as there is plenty of food, but the moment 

 the supply is short it must go towards the perpetuation of the race. In 

 the spring of 1.887, a certain crab-apple tree blossomed out to a degree 

 I never saw equalled by any other tree, but in a few months all the 

 tree, except the roots, was dead. The ground on which it stood had 

 got too dry to support it, and its dying effort went toward reproduction. 

 Pruning the roots of apple trees has a tendency to increase their fertility 

 and the yield of fruit. So far as vitality and organization are trans- 

 ferred from a parent to a child, it is death to the former. The protozoa 

 are indeed in one sense immortal. Apparently there can be no dissolu- 

 tion of a one-celled organism. Where there is a body which is com- 

 posed of single cells, the dissolution of the bonds uniting these cells 

 constitutes the death of that body even if the cells themselves should 

 live on separately. The protozoon Magosphcera is formed by cell divi- 

 sion into a many-celled body, which is no sooner complete than it breaks 

 up, the cells composing it each setting up for itself to repeat the opera- 

 tion. But there are many such simple organisms, both animal and veg- 

 etable, which, in maturing and liberating the elements which form the 

 next generation, end their own existence. Not merely the incipient 

 multicellular organisms, like the Magosphaera, lose their own identity in 



