MALE ORGANS AND ELEMENTS OF GENERATION. 879 



an inch in depth by three-quarters of an inch in length, that it then begins to retract 

 and becomes a small cicatrix at the end of seven or eight weeks. 1 



Dimensions of the Corpus Luteum at different Stages. 



Male Organs and Elements of Generation. 



There is not the same physiological interest attached to the anatomical study of the 

 male genital ia, particularly the external organs, as there is to the corresponding parts 

 in the female, for the reason that the function of the spermatozoids is accomplished 

 within the female organs, where they unite with the ovum and where the processes of 

 development take place. The anatomy of the penis and urethra has a more exclusively 

 surgical interest. As physiologists, we have to study the testicles (organs which cor- 

 respond to the ovaries, and in which the male generative element is developed), the 

 various glandular structures which secrete fluids forming a part of the ejaculated semen, 

 the mechanism of erection, by which penetration of the male organ into the vagina is 

 rendered possible, the composition of the seminal fluid and the mechanism of its ejac- 

 ulation, and the course of the semen in the generative passages of the female until it is 

 brought in contact with and fecundates the ovum. As regards the penis, it will be suffi- 

 cient to describe, as we shall under the head of coitus, the mechanism of erection and 

 of the ejaculation of semen. It will be necessary, however, to study the structure of 

 the testicles and of the various glandular organs connected with the urethra, in order 

 to understand the development of the spermatozoids aud the composition of the seminal 

 fluid. 



The Testicles. The testicles are two symmetrical organs, situated, during a rvrtain 

 portion of intra-uterine life, in the abdominal cavity, but finally descending into the 

 scrotum. Within the scrotum, which is a pouch-like process of integument, are the 



1 In 1851, Dr. J. C. Dalton published an essay on the " Corpus Luteum of Menstruation and Pregnancy." ir. which 

 he pointed out very accurately the different points of distinction between what had boon known as the false and t he- 

 true corpora lutea. These observations it is unnecessary to quote in detail, as the results wore almost idontical with 

 those obtained by Coste ; but they are peculiarly interesting, not only from the accuracy of the descriptions, but a* 

 they were made independently, and without any knowledge of the publication by Coste two years before. 



