2I 6 NORMAL HISTOLOGY. 



eight hours, or longer, within the fluids of the seminal tract. Cells 

 capable of such tenacious vitality even under the less favorable con- 

 ditions outside the body, exhibit still greater endurance when aided by 

 the favorable conditions for prolonged life afforded by the normal 

 female generative tract ; in these organs the spermatozoa no doubt 

 often retain their powers of fecundation for weeks. 



These elements successfully resist the destructive action of ordi- 

 nary reagents, as well as putrefactive changes ; this capability is 

 owing, probably, to the union of the albuminous with the calcareous 

 matters, which latter the spermatozoa contain in large quantity. 



The seminal fluid as ejaculated contains several constituents recog- 

 nizable by microscopical examination. In addition to the sperma- 

 tozoa there are usually seen spherical or cylindrical masses consisting 

 of a clear, hyaline, glassy substance derived from the seminal vesicles ; 

 numerous small, pale, delicate granules of an albuminous nature ; a 

 few round or oval nucleated cells, whose finely granular protoplasm 

 often contains fat-granules ; cylindrical epithelial cells, and the char- 

 acteristic prostatic concretions or amyloid bodies, which are yel- 

 lowish in color, spherical or triangular in form, and concentrically 

 striated. These concretions appear to be composed of an albuminous 

 substance in combination with a second which corresponds to lecithin 

 (Fiirbringer, Posner). 



On standing for twenty-four hours the semen separates into an 

 upper clear fluid and a thicker, opaque lower stratum ; the former 

 contains few morphological elements, while in the lower layer these 

 are very abundant. Subsequently, after prolonged standing, two 

 varieties of crystals are frequently encountered, those composed 

 of ammonio-magnesium phosphate and the so-called spermatic 

 crystals. According to Fiirbringer, the latter are formed probably 

 by the action of the semen on the prostatic secretion : since these 

 crystals are found almost constantly, after death, in the fluid of the 

 prostate, and not within the contents of the seminal vesicles, they 

 are more appropriately termed prostatic crystals. They occur 

 usually as prisms or pyramids, colorless, or of a slight amber tint, 

 and break readily on slight pressure. 



THE PENIS. 



The penis consists of three somewhat flattened cylindrical masses 

 of erectile tissue, the corpora cavernosa and the corpus spongi- 

 osum, capped by the conical glans, all of which are held together 

 by connective tissue and enveloped by the skin and subcutaneous 

 tissue. 



The two cavernous bodies are enclosed within a stout fibrous 

 envelope, the tunica albuginea, which reaches a thickness of about 



