IOQ 



LESSON XXIV. 



MALE AND FEMALE ORGANS OF REPRO- 

 DUCTION. 



(a) Testis. 



The testis of a dog was divided transversely into thin pieces, 

 hardened in mercuric chloride, stained in Delafield's hrematoxylin, 

 embedded in paraffin, and sectioned. Fix to slide, and mount in 

 balsam. 



Use the low power. The section is given to show the 

 general structure of the gland. Observe the fibrous tissue 

 capsule, the tunica albuginea, surrounding the gland. 

 From this septa pass into the parenchyma, and form a 

 framework for the seminiferous tubules. These are seen 

 cut in cross and oblique section. They are lined by several 

 layers of epithelial cells. Some are filled with spermatozoa. 

 Off to one side of the testis is seen the epididymis. The 

 round or oval twisted tube as seen in cross section is lined 

 by a layer of stratified ciliated columnar epithelium. The 

 wall is composed of a fibrous mucosa ; outside of this is a 

 layer of non-striped muscle tissue. Near the epididymis is 

 the vas deferens. It shows a relatively broad outer wall 

 of non-striped muscle tissue, the majority of the cells of 

 which are arranged transversely. The narrow fibrous 

 mucosa is lined by stratified ciliated columnar epithelium. 



Sketch a portion of the testis under low power, and a 

 tubule of the epididymis and the vas deferens as seen under 

 high power. 



(b) Section of the Testis Showing Spermato- 



genesis. 



Very small pieces of a guinea pig's testis were hardened for 24 

 hours in a solution composed of two parts of 2 \% osmic acid, 

 three parts of 2 % platinum chloride, and five parts of a 

 saturated aqueous solution of mercuric chloride. They were then 



