REPRODUCTIVE FUNCTIONS. 913 



ovarian tube and are carried toward the uterus by means of the cilia 

 lining the Fallopian tube. Frequently such a close contact does not 

 occur, since numerous cases of failure of the ova to enter the Fallopian 

 tube are recorded, and, as a consequence, abdominal pregnancy may 

 take place. Still, there is no doubt that the congestion of the Fallo- 

 pian tubes must result in their erection, as may be accomplished arti- 

 iicially by injection of their blood-vessels. It is probable that the cur- 

 rents set up by the continued motion of the cilia in the Fallopian tubes 

 are the main cause in leading to the entrance of the ova into the Fallo- 

 pian tubes. 



After the ovum has entered the Fallopian tube from one to three 

 days is required for its passage to the uterus. Here, if not already 

 impregnated, it may meet with spermatozoa, or ma}^ undergo fatty degener- 

 ation, although certain changes, as already detailed, may occur in the ovum 

 even when unimpregnated. 



As the Graafian follicle bursts it discharges its contents and col- 

 lapses, while in its interior remains the residue of the granular membrane 

 and a small quantity of blood, which rapidly coagulates. The vascular 

 walls of the follicle swell up, and connective-tissue proliferation gradually 

 leads to the filling up of the follicle, whose contents finally undergo fatty 

 degeneration, and from the yellow appearance thus produced the name 

 corpus luteum has been applied to this spot. If pregnancy has not 

 occurred the fatty matter is rapidly absorbed, the blood breaks up into 

 hsematin and other derivatives, while the entire mass gradually shrivels, 

 and by the end of four weeks has almost disappeared. Such a corpus 

 luteum is spoken of as a false corpus luteum. If impregnation has taken 

 place this corpus luteum instead of disappearing increases in size, so that 

 at the end of three or four months its walls are thicker and its color 

 deeper, and at the termination of gestation it may be as large as six or 

 ten millimeters in diameter, and may remain for a long time afterward. 

 Such a form is spoken of as a true corpus luteum. It is, however, prob- 

 able that too much importance has been laid upon the distinction between 

 these two forms. 



2. THE REPRODUCTIVE TISSUES OF THE MALE. The secretion of the male 

 genital organs is known as the seminal fluid, or sperm, and it is formed 

 by the secreting tubules of the testicles. It consists of a whitish-yellow, 

 sticky fluid of high specific gravity and of neutral or alkaline reaction. 

 In the seminal fluid of the horse are found 18 per cent, of solids, in that 

 of the bull 17.6 per cent., while in that of man there is only 10 per cent, 

 of solids, of which 4 per cent, consists of inorganic salts, especially of 

 calcium and magnesium phosphate. When exposed to the air it becomes 

 more fluid, and when water is added to it, it becomes gelatinous. The 

 seminal fluid as discharged from the urethra is mixed with the secretions 



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