970 MALE ORGANS OF GENERATION. 



contact at ono part, are intimately connected at another ; so that the 

 division of the mass into lobules varies greatly in its extent, and hence the 

 different estimates of the number of the lobules by different anatomists. 

 The walls of the tubuli seminiferi are composed of connective tissue, lined 

 with a basement membrane, and sometimes presenting an epithelium, com- 

 posed of nucleated granular corpuscles, but, in the period of activity, 

 filled with cells of different sizes, without regular arrangement or any lumen 

 in the interior. lu aged subjects there is much fatty matter accumulated 

 in these cells, so that the tubes acquire a yellower colour than in early life. 

 The walls of the tubes are sufficiently strong to bear the forcible injection of 

 mercury, which has been commonly employed for their investigation. 



The mode in which the tubes commence appears to be twofold viz., by 

 free closed extremities, hid within the lobules, but more frequently by ana- 

 stomotic arches or loops. After an exceedingly tortuous course, they at 

 length, in approaching the corpus Highmorianum, lose in a great measure 

 the convoluted disposition, becoming at first slightly flexuous and then 

 nearly straight. The separate tubuli of each lobe, and then those of adjoin- 

 ing lobes, unite together into larger tubes, which enter the fibrous tissue of 

 the mediastinum and, being placed amongst the branches of the blood-vessels, 

 form the next order of the seminal ducts. 



These, which, from their comparatively straight course, are named tubuli 

 recti or vasa recta, are upwards of twenty in number, and are from -^th to 

 7 J 0th of an inch in diameter. They pass upwards and backwards through 

 the fibrous tissue, as already stated, and end in a close network of tubes, 

 named by Haller the rete vasculosum testis, which lies in the substance of the 

 corpus Highmorianum, along the back part of the testicle, but in front of 

 the primary subdivisions of the spermatic blood-vessels before these enter 

 the gland. The tubes composing the rete have very thin walls. According 

 to Kolliker, indeed, they have none, but are mere 

 Fig. 678. channels in the fibrous membrane, lined with squamous 



, epithelium. They conduct the secretion to the upper 



IJ end of the testis, where they open into the vasa 



efferentia. 



Fig. 678. DUCTS OF THE TESTICLE INJECTED WITH MERCURY 

 (from Haller). 



a, body of the testicle ; 6, tubuli in the interior of the gland ; 

 c, rete vasculosum ; d, vasa efferentia terminating in the coni- 

 vasculosi; e, /, g, convoluted canal of the epididymis ; k, vas 

 deferens ascending from the globus minor of the epididymis. 



The vasa efferentia are from twelve to fifteen, or 

 sometimes twenty in number; they perforate the tunica 

 albuginea at the upper end of the posterior border of 

 the testicle, beneath the globus major of the epididy- 

 mis, of which they may be said to form a part, and 

 in the convoluted canal of which they ultimately 

 terminate. On emerging from the testis, these vasa 

 efierentia are straight, but, becoming more and more convoluted as they 

 proceed towards the epididymis, they form a series of small conical masses, 

 the bases of which are turned in the same direction, and which are named 

 com vasculosi. Their walls contain, besides fibrous tissue, longitudinal and 

 transverse muscular fibres. The largest of the cones is about eight lines 



