e 



/ 



.so/ 





SECT. 197.] THE SEMINAL TUBULES. 429 



then arises the simple canal of the epididymis, which measures 

 0'i6'" to o'l"' in thickness. This canal, wound in a well-known 

 manner, forms the body and tail of the epididymis, and usually 

 gives oft' from its lower end a caccal process (vas aberrans of Nailer). 

 It then passes into the seminal duct, which is at first convoluted, 

 and only £'" to -\" wide, but soon becomes straight and %" to 1'" 

 in diameter. The epididymis also possesses a fibrous coat of 

 greyish-white colour, but this is very thin (+'")• 



§ 197. Structure of the Seminal Tubules, Sper ma. — The seminal 

 tubules have a more solid wall in proportion to their diameter 

 than other glandular canals, and they consist of a, fibrous coat and 

 an epithelium. The former has an average thickness of croc^"' to 

 croo-j."', but ranges between o - oo24"' and 0'005"'. It is composed 

 of connective tissue, indistinctly fibrillated, with longitudinal nuclei, 

 no muscular fibres, and rarely with any indication of elastic 

 fibrillae : it is pretty firm and extensile. A simple layer of round- 

 ish or polygonal cells, o - oo5'" to o'Oo8" Fj g- !< 9 - 

 in diameter, with an occasional indication » 

 of a membrana propria beneath them, 

 lies upon the inner surface of the tube, \ %-'■'• • : £ \ 

 and completes the glandular canal, j ,.. ■'%- i 

 whose wall thus becomes of 0'007'" to 



o*oi in its total thickness. In young V* 



persons, these cells are pale and finely \ " : 1 1 



granular; but in older persons, more and \\% 

 more fat granules collect in them, and < 



these soon occasion a slightly yellowish y'Jp^ — -" (| 



or even brownish colour of the seminal 



. . . . Seminal tubule of man, mag- 



tubules. TlllS Condition of the tubules is nifi ed 350 times, a. fibrous coat 



. . with longitudinal nuclei; b. clear 



very frequent even m men of middle age, border, indicating, probably, a 



,.. ■it/' • it basement membrane; c. epithe- 



and is invariably found in old persons. Hum. 

 The ductuli recti possess the same structures as the tubules 

 of the testicle ; on the other hand, in the rete testis, a special 

 fibrous coat cannot be distinguished, the canals here appearing 

 more like spaces lined with epithelium in the dense fibrous tissue 

 of the corpus Highmori. In the coni vasculosi, the fibrous coat 

 again makes its appearance, and soon there is added a layer of 

 smooth muscular fibres, which run in a transverse and longitudinal 

 direction, and are recognisable in canals of 4"' to +'" in diameter. 

 The thicker parts of the canal of the epididymis are constructed 

 exactly like the vas deferens (q. v.). The epithelium lining the epi- 

 didymis has hitherto been regarded as a simple layer of cylindrical 



