618 SPECIAL HISTOLOGY. 



In the investigation of the suprarenal glands, the larger Mammalia 

 ought, in the first place, to be chosen, and not till afterwards should 

 they be studied in Man. The cortical portion is readily examined when 

 its elements contain but little fat, and, above all, perpendicular sections 

 of fresh specimens, or of such as have been hardened in alcohol and in 

 chromic acid, which are afterwards to be rendered transparent by soda, 

 are to be recommended. The medullary substance, even in animals, is 

 very easily disintegrated, so that its elements are either not to be seen 

 at all in the normal state, or only partially, although they are occa- 

 sionally very beautifully displayed without any addition, as well as in 

 chromic-acid preparations. In animals, the nerves are very easily dis- 

 cerned in fine sections, after the addition of soda; and when their ex- 

 ternal visible points of entrance are exactly hit upon in the making of 

 the section, their course through the cortical substance is readily brought 

 into view. For the vessels, injections should be employed, which are 

 best effected in the Sheep or sucking Pig, and which readily succeed 

 when made, as well from the arteries as from the non-valvular veins. 



Literature. Nagel. "Diss. sistens ren. succent. mammal, descript.," 

 Berol., 1838," and Mull. "Arch.," 1836; C. Bergmarm, " Diss. de 

 glandulis suprarenal," c. tab. Gott., 1839 ; A. Ecker, " Der feinere 

 Bau der Nebennieren beim Menschen," u. den 4 " Wirbelthierclassen," 

 Braunschweig, 1846, und Art. "Blutgefassdriisen," in Wagner's 

 " Handw. d. Physiologic," Bd. IV. 1849 ; H. Frey, Art. " Suprarenal 

 Capsules," in Todd's " Cyclop, of Anat.," Oct., 1849. 



[H. Gray, " On the development of the ductless Glands in the Chick," 

 " Phil. Trans." 1852. TRS.] 



OF THE SEXUAL ORGANS. 

 A. MALE SEXUAL ORGANS. 



196. The male sexual organs consist, 1, of two glands for the se- 

 cretion of the semen, the testes, which, together with special tunics, the 

 tunicce vaginales, are contained in the scrotum ; 2, of their efferent 

 canals, the vasa deferentia and ejaculatory ducts with their appendages, 

 the vesiculce seminales ; 3, of the copulatory organs, the penis and its 

 muscles ; 4, and lastly, of special accessory glands, the prostate and 

 Cowpers glands. 



197. The testicles, testes, are a couple of true glands, containing 

 within a special tunic, the tunica albuginea s. fibrosa, the secreting ele- 

 ments, in the form of complexly convoluted tubules, the spermatic tubes 

 or tubuli seminiferL The tunic is a white, dense and thick membrane, 



