THE SIRE. 99 



takes place at other times in them (with the single 

 exception of the genus Dimana). 



"10. The semen retains its fructifying power for some 

 days if it is contained within the walls of the uterus or 

 vagina, but soon ceases to be fruitful if kept in any 

 other vessel. Hence, although the latter part of the 

 time of heat is the best for the union of the sexes, be- 

 cause then the ovum is ready for the contact with the 

 semen, yet, if the semen reaches the uterus first, it will 

 still cause a fruitful impregnation, because it remains 

 there (or in the Fallopian tubes) uninjured until the 

 descent of the ovum. 



"11. The influence of the male upon the embryo is 

 partly dependent upon the fact that he furnishes a por- 

 tion of its substance in the shape of the sperm-cell, but 

 also, in great measure, upon the effect exerted upon the 

 nervous system of the mother by him. Hence the pre- 

 ponderance of one or other of the parents will, in great 

 measure, depend upon the greater or less strength of 

 nervous system in each. No general law is known by 

 which this can be measured ; nor is any thing known of 

 the laws which regulate the temperament, bodily or 

 mental power, color or conformation, of the resulting 

 offspring. 



"12. Acquired qualities are transmitted, whether 

 they belong to the sire or dam ; and also both bodily 

 and mental. As bad qualities are quite as easily trans- 

 mitted as good ones, if not more so, it is necessary to 

 take care, that, in selecting a male to improve the stock, 



