n6 PRACTICAL HISTOLOGY. 



THE MALE GENERATIVE ORGANS. 



THE TESTIS. 



PREPARATION, (a) Chromic acid and Spirit Mixture. Use the testis of a dog, rabbit, or 

 guinea-pig. Make several cuts across the testis with a sharp razor, taking care to squeeze the 

 organ as little as possible, and place it in the above fluid. Change the fluid frequently, and 

 at the end of ten days transfer it to weak, and then to strong, spirit. Make transverse 

 sections by freezing through the whole organ ; stain them with logwood, and mount 

 them in dammar. They are apt to fall to pieces, but by floating the section in water all 

 difficulty is overcome. 



(i>) Miiller's fluid. Harden the testis for three weeks in Miiller's fluid, and then in spirit. 

 The testis is rendered very tough by this method, and it is less apt to fall to pieces. 



(c) Interstitial Injection of Osmic Acid. Inject into the testis, with a subcutaneous syringe, 

 a one per cent, solution of osmic acid, and harden the organ in alcohol. This method shows 

 the intertubular connective tissue very well after being stained with logwood. 



Transverse Section of the Testis. EXAMINATION (L). Observe the capsule, consisting of 

 an outer layer the tunica adnata, or the visceral layer of the tunica vaginalis and an inner, 

 dense, fibrous coat the tunica albuginea. Between these two layers oval openings are seen : 

 they are sections of lymphatic vessels. From the capsule septa radiate inwards towards the 

 corpus Highmori, so as to subdivide the organ into a series of compartments, each one of 

 which is filled with small convoluted tubes the tubuli seminiferi which, of course, are cut 

 in every possible direction. These compartments, when filled with the tubules, constitute the 

 lobuks of the testis. These septa have a decidedly lamellar structure, and they carry the 

 large blood- and lymph-vessels. Note these tubes of nearly uniform diameter, and observe the 

 small amount of intertubular connective tissue, which takes the form of lamellae of connective 

 tissue covered with endothelial cells. The interlamellar spaces communicate freely with each 

 other, and form the origin of the lymphatics of the testis (p. 1 1 8). 



In some animals (dog, cat, and boar), columns of peculiar granular, nucleated cells are 

 found between the tubules. In some animals (guinea-pig) they are pigmented, but their exact 

 nature is unknown. 



The tubuli seminiferi are relatively large, wavy, and convoluted tubes of uniform diameter, 

 and are cut in every direction. Each tube is seen to consist of a thick membrana propria, of 

 a clear hyaline character, with flattened nuclei in it, so that it is probably endothelial in its 

 nature. It is more or less completely filled with seminal cells. It may be possible to trace the 

 tubules in their course towards the corpus Highmori, where they empty themselves into the vasa 



