198 NORMAL HISTOLOGY. 



The corpus spongiosum is enclosed in a dense con- 

 nective-tissue sheath which contains elastic fibres 

 and a few smooth muscle-cells. From this a multi- 

 tude of narrow trabeculae or septa, composed largely 

 of smooth muscle-tissue, pass inward in various 

 directions, and dividing and subdividing, form an 

 intricate series of spaces, which are the above-men- 

 tioned blood-cavities. This system of trabeculae and 

 septa is continuous, within, with the submucosa of 

 the urethra. 



The erectile tissue is most abundant below the 

 urethra ; above, the blood is collected into venous 

 trunks, which, joining similar trunks from the cor- 

 pora cavernosa above, convey the blood away from 

 the part. The corpora cavernosa are similar in 

 structure to the corpus spongiosum. 



TECHNIQUE. 



Transverse Sections. The corpus spongiosum and the 

 posterior portions of the urethra are dissected from the 

 remainder of the penis and hardened in potassium bichro- 

 mate and alcohol. Transverse sections from the different 

 regions are stained double and mounted in balsam. 



FEMALE GENERATIVE ORGANS. 

 THE OVARY. 



The ovary is a gland whose vesicular alveoli have 

 no excretory ducts, but discharge their contents by 

 periodic rupture at the surface of the organ. These 

 alveoli are called Graafian follicles, and the ovum 



