IMPREGNATION OF THE OVUM. 573 



IMPREGNATION OF THE OVUM. 



Male Sexual Functions. 



The fluid of the male, by which the ovum is impregnated, 

 consists essentially of the semen secreted by the testicles ; and 

 to this are added, as necessary, perhaps, to its perfection, a 

 material secreted by the vesiculae serainales, in which, as in 

 reservoirs, the semen lies before its discharge, as well as the 

 secretion of the prostate gland, and of Cowper's glands. Por- 

 tions of these several fluids are, probably, all discharged, to- 

 gether with the proper secretion of the testicles. 



The secreting structure of the testicle is disposed in two 

 contiguous parts (1), the body of the testicle inclosed within 

 a tough fibrous membrane, the tunica albuginea, on the outer 

 surface of which is the serous covering formed by the tunica 

 vaginalis, and (2) the epididymw. The vas deferens, the main 

 trunk of the secreting tube, when followed back to its origin, 

 is found to pass to the lower part of the epididymis, and as- 

 sumes there a much less diameter with a very tortuous course ; 

 with its various convolutions it forms first the mass named 

 globus minor, then the body, and then the globus major of the 

 epididymis. At the last-named part, the 

 duct divides into ten or twelve small 

 branches, the convolutions of which form 

 coniform masses, named coni vasculosi ; 

 and the vessels con tinned from these, the 

 vasa efferentia, after anastomosing, one 

 with another, in what is called the rete 

 testis, lead finally through the tubuli recti 

 or vasa recta to the tubules which form 

 the proper substance of the testicle, 

 wherein they are arranged in lobules, 

 closely packed, and all attached to the 

 tough fibrous tissue at the back of the 

 testicle. 



The seminal tubes, or tubuli seminiferi, 

 which compose the proper substance of 

 the testicle, are fine thread-like tubules, 

 formed of simple homogeneous membrane, measuring on an 

 average T i T th to ^^h of an inch in diameter, and lined with 

 epithelium or gland-C3lls. Rarely branching, they extend as 

 simple tubes through a great length, with the same uniform 

 structure, and probably terminate either in free closed extremi- 

 ties or in loops. Their walls are covered with fine capillary 

 bloodvessels, through which, reckoning their great extent in 



