THE ALUMNI JOURNAL. 



diameter and consists of an outer clear 

 membrane called the vitelline mem- 

 brane, this is surrounded by the cells of 

 the discus proligerus. Within the cells 

 of the discus proligerus is a layer of 

 •epithelial cells called the corona radiata, 

 and these are in immediate contact with 

 the vitelline membrane or zona radiata. 

 within the vitelline membrane is a clear 

 space to the fact that the vitellus or yolk 

 is smaller than the space it is contained 

 in, this space is called the periveteline 

 space. Continuing our description from 

 without inward, the next substance that 

 presents itself is the vitellus itself, it is 

 limited externally by a translucent area 

 called the outer clear space. Next this 

 and internall5^ is an accumulation of 

 small granules, the protoplasmic zone, 

 and within this larger granules the 

 ■dentoplasmic zone. 



The germinal vesicle is imbedded in 

 the vitellus and contains the germinal 

 spot. 



Mechanism of the Discharge of the 

 Ovum. — A ripe Graafian follicle meas- 

 sures f to |- inch, and presents itself as 

 a rounded elevation surrounded by blood- 

 vessels, on the surface of the ovum. 



At its most prominent portion is a 

 small ovoid space that is devoid of blood- 

 vessels, and it is this spot that finally 

 gives way and the ovum is propelled 

 into the fimbriated extremity of the fal- 

 lopian tube. 



The changes that take place in the 

 Graafian follicle subsequent to the dis- 

 charge of the ovum, result in the forma- 

 tion ot the corpus luteum. The changes 

 described above usually take place near 

 the menstrual period, and it is probable 

 that the discharge of an ovum is precip- 

 itated by the sexual act. Still, ovula- 

 tion may take place entirely indepen- 

 dently of these two phenomenae. 



Menstruation occurs in human females 

 about every 28 days. The changes that 



take place in the viterus are simple 

 enough. The mucous membrane lining 

 becomes thickened, thrown into folds 

 and largely distended with capillary 

 blood vessels. These blood vessels rup- 

 ture and the fluid is discharged by the 

 vagina. Menstruation occupies between 

 3 and 8 days, and when it has ceased the 

 mucous membrane returns to its normal 

 state. 



Male Organs of Generation. — The 

 chief physiological interest attached to 

 the anatomy of these organs relates to 

 the testicles. As regards the penis, it 

 will be necessary to do little more than 

 describe it in a general way. 



The Testicles are two ovoid organs 

 contained in the scrotum. The tunica 

 vaginatis is a short sac that lines the 

 scrotum and is reflected over the body of 

 the testicle and the spermatic cord. The 

 spermatic cord is composed of the vas de- 

 ferens and the blood vessels that nourish 

 the testicle and is the avenue through 

 which the male element of generation 

 passes on its way toward the penis. 



Beneath the tunica vaginalis are the 

 testicles with their proper fibrous coat. 



These organs are ovoid, flattened and 

 measure r}^ inches in length, about i^ 

 inches from before backward, and nearly 

 an inch from side to side. They weigh 

 about three-quarters of an ounc each. 



The proper fibrous coat of the testicle 

 is called the tunica albuquila. It is 

 thick and strong, and is simply for pro- 

 tection of the contained structures. Sec- 

 tions of the testicle show that a process 

 of the covering subdivides the testicle 

 into two compartments ; the upper is 

 called the Corpus Highmorianum, the 

 lower is subdivided again into a number 

 of lobules, which contain the tubes that 



create the semen. 



These tubes exist to the number of 



about 840 in each testicle. Each tube 



represents a tangled mass. When un- 



