298 Dynamic Theory. 



individual, it is said to be rare that self impregnation occurs. One suf- 

 ficient reason of this is that usually the production of ova and of sper- 

 matozoa does not take place simultaneously. There has been such a 

 differentiation of the sex elements that the same sort of ' ' protoplasmic 

 rythm," which developes one kind will not develop the other ; arid a& 

 Geddes & Thomson say, ' ' Antago n istic protoplasmic ry thms may rap- 

 idly alternate, but cannot coexist. " So that by reason of this alterna- 

 tion in the production of the sexual elements, they are not to be found 

 ready for each other in the same individual ; but in a community, or 

 tribe, it will always happen that the male elements produced in one in- 

 dividual, will be simultaneous with the female elements produced by 

 another. The habitat of most hermaphrodite animals is the water, and 

 the ova and spermatozoa thrown off into it are drifted about and find 

 each other by accident, or the spermatozoa are thrown off by one and 

 find their way to ova in or from the female glands of another. In the 

 case of hermaphrodite plants the male pollen is carried about in the air, 

 or by flying insects, and thus reaches the ovules in distant plants which 

 may be read}^ for it. In cases where the male elements happen to be 

 furnished by an exceptionally vigorous individual, and fall upon female 

 elements of inferior vigor, or vice versa, the result must be organisms 

 in which the equality of sex function is disturbed, some individuals be- 

 ing more male than female, and vice versa. This sort of differentiation 

 carried to an extreme results in the complete establishment of unisex- 

 uality in which one individual is the exclusive possessor of the male or- 

 gans and another the female. Embryology proves that this is the pro- 

 cess that has taken place. 



It may be asked why it is that when a cell has reached such a size 

 that its cover or surface is in just the right proportion to allow the sub- 

 stance within to get its proper nourishment and respiration, and get 

 rid of its waste matters and no more, such cell does not simply stop 

 growing, and remain an adult indefinitely, instead of breaking up and 

 starting over again? We can answer this question provided we can an- 

 swer another, which should have the precedence; viz. , why did the cell 

 in the first place take up nourishment and grow at all? A speck of pro- 

 toplasm, consisting of a chemical [union of four elements, viz. , oxygen, 

 hydrogen, nitrogen and carbon, and held together by the polar forces of 

 chemical affinity, is necessarily in contact with its environment air, 

 water, earth, light and heat. This direct contact subjecting the out- 

 side of the body to stimulations different from those assailing the in- 

 side, develop the coat or cover, and they develop in the body a shifting 

 and movement of the particles composing it, that entails loss of some of 

 the molecules. When such loss occurs the cell is said to be hungry, 

 and if it is in contact. with nutritive matter it absorbs some of it to re- 



