448 THE TESTICLE. 



not free, but are embedded in a sort of protoplasmic trabecular net- 

 work within which they are formed. Tliis was first stated by Sertoli, 

 in 1864, and more recently a detailed description of such a delicate 

 trabecular structure has been given by Merkel, whose views are sup- 

 ported by several other observers. (Merkel, in Da Bois-Reyraond's 

 Archiv, 1869 and 1871, andLaValette St. George, in Schultze's Archiv, 

 vol. i.) On the other hand it is asserted as the result of renewed ob- 

 servations that the alleged framework is the product of artificial pro- 

 cesses. (Mihalkovics, in Lud wig's Arbeiten, 1874.) It seems most 

 probable, therefore, that the seminal or spermatic cells are produced as 

 in other tubular glands by development from the layer of cells lying 

 originally on the inside of the basement membrane of the tubes. (Kul- 

 liker's Handbuch, 18G7, p. 526.) 



The intervals between the glandular tubes are occupied by blood- 

 vessels, lymphatics and nerves, embedded iu a peculiar tissue of a 

 rather undefined character, but presenting a large quantity of the 

 nuclear and molecular elements, so that Henle compares it to the 

 cortical substance of the brain, or the contents of ganglionic cells. In 

 this substance there are large interstitial spaces lined with flat nuclear 

 epithelium, in whicli Ludwig and Torasa have shown that the lym- 

 phatics of the testicle commence. ("Wien. Sitzungsbericht, vol. xliv. 

 p. 221, 1862.) 



The vasa recta pursue a comparatively straight course ; they are 

 upwards oi twenty in number, and are from -g^^th to -Jo^li of an inch iu 

 diameter. They pass upwards and backwards tlirough the fibrous tissue, 

 as already stated, and end in a close network of tubes, named by Haller 

 the rde rasculosum testis, which lies in the substance of the corpus 

 Highmori, along the back part of the testicle, but in front of the pri- 

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

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

 Kcilliker, indeed, they have none proper to them, but are mere channels in 



Fig. 320. Fig. 320. — Ducis of the Testicle injected with Mercury 



(from Haller). 



a, body of tlie testicle ; h, tubiili in tlie interior of the gland ; 

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

 vasculosi ; c, f, g, convoluted canal of the epididymis ; h, vas 

 deferens ascending from the globus minor of the e^Hdidymis. 



the fibrous stroma, lined with squamous epithelium. 

 According to Henle the epithelium of the tubes 

 in the rete testis already begins to assume the 

 columnar character which it possesses in the after 

 parts of the ducts. They conduct the secretion to 

 the upper end of the testis, where they open into 

 the vasa efferentia. 



Tlie vasa eS'erentia are from twelve to fifteen, 



or sometimes twenty in number ; they perforate the 



ftf^*|/ tunica albuginea "beneath the globus major of 



'^' the epididymis, 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 eflerentia are straight, but, 



becoming more and more conYoluted s-3 thej proceed towards tha 



