CH&<PTE<R XVII. 



SEXU&L GENE<ft&TION. 



Ovulation. 



The function of generation is dependent upon the combined action of 

 two sets of organs, in each of which a peculiar product originates, quali- 

 fied for union with the other so as to produce a new individual. 



Throughout nature this primary principle exists; the essential charac- 

 ters of the organs of generation in the different classes of organized 

 beings are universal. A study of botany discloses the fundamental law, 

 modified in the different varieties. In the lily, violet, etc., the male and 

 female organs both exist upon one stalk. In some cases, separate male 

 and female flowers are found on the same plant; in others, as in the wil- 

 low, poplar and hemp, they are situated on different growths, which 

 otherwise resemble each other. 



In animals the essential parts of the female generative system are 

 called the ovaries. In them is produced the germ or egg, which is capa- 

 ble of being developed into a young animal, when fecundated or made 

 fruitful by a substance which is produced in the testes of the male. 



In some of the lower animals both sets of generative organs exist in the 

 same individual. In them the ovaries are first matured and perform their 

 functions, after which the male organs become active. Thus they are 

 literally first female and afterwards male, exercising their appropriate 

 actions at different ages. 



In all the higher classes of animals the two sets of generative organs 

 are situated in separate individuals, dividing the species into two sexes, 

 the male and female, each having accessory organs which give rise to a 

 greater dissimilarity in their anatomy. 



The product of the ovaries, or egg, is a globular body, which in quadru- 



