Hitman Physiology. 255 



and the excitement of the passions hasten puberty, and exag- 

 gerate and disorder the corresponding masculine function. 



The microscope does not reveal to us what takes place in 

 the act of impregnation or conception, or what change is pro- 

 duced by the contact of the spermatozoon with the ovum. The 

 egg of the maiden hen contains the rudiments of the chick, but 

 it can never be hatched. The warmth that brings life and 

 development to the impregnated egg, only hastens the putri- 

 faction of the unimpregnated. The unimpregnated eggs of the 

 frog quickly putrify; but if the male element be soon brought 

 to them they expand into living creatures. In this case the 

 spermatozoa can be seen to become buried in the gelatinous 

 covering of the eggs, they pass through the membranes which 

 cover them, and are probably absorbed into the ovum. 



The blood goes to the testes in long, slender, tortuous 

 arteries, presenting an extensive surface for the action of ner- 

 vous energy, and there is no doubt that the best blood of the 

 body is selected to form the semen, and that it is changed and 

 perfected, first in these arteries and then in the wonderfully 

 fine and convoluted tubes of the testes. The same arteries 

 that supply blood to the testes in the male, furnish the circula- 

 tion of the ovaries in the female ; and the same nervous centres 

 furnish the nerve energy and directing intelligence ; but what 

 makes the difference in action forming germ cells in one sex, 

 and sperm cells in the other or what makes sex, must probably 

 remain among life's inscrutable mysteries. " Arrest of develop- 

 ment" will not account for it, and if it did, what causes arrest 

 of development? "Male and female created He them." 



At the age of puberty remarkable changes take place in both 

 sexes. Boys and girls differ indeed from their tenderest years. 



c. Showing a circular spot on the surface, which some suppose to be o 

 sucker, d. Shows an elongation from the head, like a proboscis, e. Granules, 

 or cells, in which other zoosperms are preparing. 



