THE GERM-CELL. 519 



observe the disappearance of the mulberry mass, and its replacement by 

 a fasciculus of spermatic filaments, although the exact metamorphosis by 

 which the granular cellular mass formed the bodies of the spermatozoids 

 could not be detected. The spermatic filaments, Dr. Burnett thinks, are 

 not formed, as stated by Kolliker, by a deposit from the contents of the 

 sperm-cell or nucleus, but by an elongation of the nucleus itself. The 

 body of the spermatozoid is developed from the cell, while the tail is 

 probably subsequently formed by an accumulation of minute particles." 

 (Kolliker, Am. ed., p. 625.) 



In man, the production of spermatozoa commences between the four- 

 teenth and sixteenth year, the time of puberty, and continues until the 

 sixty-fifth or seventieth, or even much longer. This period of commence- 

 ment is marked by a great change in the physical and moral constitution. 



The spermatic fluid of mule animals contains no spermatozoa. This 

 fact has been established in an interesting manner by Wagner in the case 

 of birds, of which many of those which are domesticated readily cross. 

 There can be no doubt that these bodies are the essential portion of the 

 fluid, and that it is their action upon the ovum which establishes its fer- 

 tilization. 



There has been much controversy whether the spermatozoa present 

 traces of organization, properly speaking. Though it is convenient to 

 designate their dilated portion as the head, and the filament as the tail, 

 it has never yet been established that any thing answering to a true 

 structural arrangement exists, and, upon the whole, it may be concluded 

 that the appearances which have been by some supposed to indicate or- 

 ganization are, in reality, only an optical illusion. 



2d. Of the Germ-cell. In mammals the female reproductive appara- 

 tus consists essentially of the ovaries, oviduct, and uterus. Female 



The ovaries are two ovoid bodies situated on either side ductive appa- 

 of the uterus. They consist of a stroma in which vesicles r 

 are imbedded : these vesicles give origin to the ova. In the manner to 

 be presently described, the ova, being received at the fimbriated extrem- 

 ities of the Fallopian tubes, those tubes being therefore appropriately 

 termed oviducts, are carried into the cavity of the uterus. 



At the time of puberty in the human female, which occurs between 

 the 14th and 16th year, a physical and moral change takes 



i . ^ C-Vt. t: i j n j i . The catamenia. 



place, answering to that which has been already alluded to 

 as occurring in the male. From this period a sanguinolent discharge 

 makes its appearance monthly : it is the catamenia. The interval from 

 time to time is commonly estimated at four weeks ; it varies, however, 

 with individuals, and it is said also with climates, the discharge occurring 

 in the hotter more frequently, and in greater quantity. It is essentially 

 blood, which has been deprived of its quality of coagulating by inter- 



