THE EPIDIDYMIS. 233 



long motile flagellum, the tail. The actual rate of their unobstructed progress 

 has been estimated at from 1.5-3.5 mm - P er minute. Although less vigorous 

 than in the semen, the spermatozoa often display motion in the secretion of 

 the testicle, as taken from the epididymis. Spermatozoa may continue to 

 exhibit motion for a long time in the body for several days after death; 

 in properly guarded microscopical preparations of fresh semen movements 

 have been observed after the lapse of over eight days. They may remain 

 active probably for even a longer period within the female generative tract. 

 Although resisting a wide range of temperature, spermatozoa immediately 

 succumb to aqueous solutions containing acids or metallic salts; alkaline 

 solutions, on the other hand, stimulate their motion. Ejaculated semen is 

 a composite fluid, consisting of the secretions of the testicle diluted with those 

 from the seminal vesicles, the prostate and the bulbo-urethral glands. It has 

 been estimated that each cubic millimeter of semen contains approximately 

 60,000 spermatozoa. 



THE EPIDIDYMIS. 



The epididymis, the greatly convoluted beginning of the spermatic duct, 

 is a crescentic body that covers the posterior border and part of the outer 

 surface of the testis. Its enlarged upper end or head, the globus major, is 

 succeeded by the tapering body, at the lower end of which is a second but 

 smaller enlargement, the globus 'minor. The bulk of the globus major 

 depends upon the aggregation of from twelve to fifteen conical masses, the 

 lobuli epididymidis, formed by the efferent ducts and their tortuosities, the 

 coni vasculosi, that pass from the upper end of the testis and connect the rete 

 testis with the canal of the epididymis. The latter, also called the ductus 

 epididymidis, begins in the globus major, receives the efferent ducts and be- 

 comes greatly convoluted, the remarkably wound single tube measuring, 

 when unravelled, from 5-5.5 meters or from 18-20 feet. 



The efferent ducts form the conical lobules of the globus major, which 

 masses, together with the convolutions of the canal of the epididymis, are 

 enclosed by a fibrous envelope resembling but less robust than the capsule of 

 the testis. The individual tubules and convolutions are held together by deli- 

 cate vascular connective tissue. The transition of the irregular channels of the 

 rete testis into the efferent ducts (.2-. 5 mm. in diameter) is marked by an 

 abrupt change in the character of the lining epithelium, the low cuboidal cells of 

 the former giving place to irregularly ciliated columnar ones within the ef- 

 ferent ducts. This epithelium, moreover, is composed of cells of unequal 

 height, some forming groups of tall cylindrical elements, with or without cilia 

 and variably pigmented, while others occur as groups of low cuboidal cells. 

 In consequence of this inequality, the lumen of the efferent ducts is irreg- 

 ular and the surface of the mucous membrane modelled with minute depres- 

 sions corresponding to the areas covered by the lower cells. In some 'cells 

 the border of cilia is replaced by clear caps, which have been interpreted as 

 secretion. Outside a well defined basement membrane the tubules are sur- 

 rounded with a layer of circularly disposed unstriped muscle, intermingled 

 with numerous elastic fibres. 



The canal of the epididymis, from .4-. 5 mm. in diameter, is lined 

 throughout with stratified columnar epithelium, consisting of a deep layer 

 of small rounded cells, next the well defined basement membrane, and a 

 superficial layer of tall columnar elements, that contain pigment particles and 

 secretion granules. The free surfaces of the columnar cells bear exceptionally 

 long cilia, which, however, are not motile and adhere into conical tufts sur- 



