THE REPRODUCTIVE GLANDS. 419 



cent, of lactose. It thus contains a smaller amount of water than 

 the milk. The secretion ceases several weeks after birth. 



Uterine milk is a fluid which can be obtained from the uterine 

 glands of ruminants after careful separation of the chorion villi. It 

 has the appearance of cream, and is morphologically and chemically 

 quite similar to colostrum. 



THE REPRODUCTIVE GLANDS. 



The Testicles. Of the chemical composition of the testicles as 

 such, little is known. Aside from the albuminoids which enter into the 

 construction of the supporting tissues of the glands, and the extrac- 

 tives which are common to all organs of the body, we notably meet 

 with albumins, among which the nucleins are especially abundant. 

 In addition, serum-albumin, a globulin, and a substance which 

 apparently belongs t'o the hyalins, have been encountered. Of mineral 

 salts, we notably meet with the chlorides of sodium and potassium. 

 The reaction of the glands is alkaline. 



The Semen. The specific product of the functional activity of 

 the testicles is represented by the semen, and notably its morpho- 

 logical elements, the spermatozoa, which result from the spermato- 

 genetic cells through a complicated process of metamorphosis, in 

 which the cell-nuclei are especially concerned. On its passage to 

 the outside the testicular fluid is mixed with the secretions of the 

 seminal vesicles, the glands of Cowper, and notably with the secre- 

 tion of the prostate gland. 



Recently ejaculated semen is a markedly viscid, white or yellow- 

 ish-white, opaque fluid of the appearance of milk, in which micro- 

 scopical examination reveals the presence of innumerable sperma- 

 tozoa, and a few hyalin globules, which are derived from the seminal 

 vesicles ; further, isolated testicular and urethral cells, prostatic 

 corpuscles, and cellular bodies enclosing lecithin granules, besides a 

 large number of free granules, which are apparently of an albumin- 

 ous nature. In a fresh specimen the normal spermatozoa are ac- 

 tively motile, and continue so for a variable length of time if evapo- 

 ration is prevented. 'The movements are in all likelihood analogous 

 to those of the cilia of certain epithelial elements of the body, and are 

 arrested by the addition of water, dilute acids, alcohol, ether, strongly 

 alkaline solutions, etc. In dilute alkaline solutions, on the other 

 hand, and those of the neutral salts they continue for a long time. 



Semen is heavier than water, and foils to the bottom as a jelly- 

 like mass : at the same time a light flocculent precipitate develops, 

 which consists of the so-called fibrin of Henle. On exposure to the 

 air it is apparently coagulated, but later becomes liquid, as before. 

 Its reaction is neutral or slightly alkaline. 



Testicular semen, in contradistinction to that which has been 

 ejaculated, is said to be odorless. After emission, however, an odor 

 develops which is suggestive of glutin, and is supposedly referable 



