SPERMATOZOA. 



181 



c 



odorous secretion of which enters into the formation of the 

 smegma. The raucous covering of the glans is reflected over 

 the inner surface of the prepuce and at its margin merges 

 into the skin. 



The semen, as finally ejaculated, consists of an immense 

 number of special cellular elements (spermatozoa) suspended 

 in fluid (liquor seminis), together with granular, crystalline, 

 and adventitious matter. The liquor seminis is derived from 

 various parts of the seminal tract, 

 especially the seminal vesicles, pros- FIG. 70. 



tate, and Cowper's glands. It is a 

 muco-al numinous fluid containing 

 various chemical ingredients. It 

 exhibits fine granular matter (cel- 

 lular and protoplasmic debris), and, 

 in small number, cast-off epithelium- 

 cells, stray leukocytes, clear " hyaline 

 bodies" from the seminal vesicles, 

 fat and lecithin particles, and the 

 small prostatic concretions or " amy- 

 loid bodies." After standing, crys- 

 tals are deposited in the semen, es- 

 pecially characteristic slender octa- 

 hedral crystals of spermin phosphate. 



The spermatozoa of different species 

 of animals exhibit characteristic dif- 

 ferences though the general structure 

 remains similar ; the same is the case 

 with the homologous pollen of plants. 



The spermatozoon of man (Fig. 70) 

 is made up of a head 3 to 5 fj. long, 

 a middle piece 5 or 6 // long, and a 

 tail 40 to 50 // long. The head is 

 of a flattened oval or pyriform shape, 

 to the large end of which the middle 

 piece or tail is attached. The middle piece is a cylindrical 

 segment more or less distinctly marked off from the tail. The 

 tail is a long fine filament or flagellum, tapering to a point ; it 

 possesses an "axial fibre" surrounded (except for a short dis- 



d 



e 



Human spermatozoa (Bohm and 

 Davidpff ). The left figure is a 

 side view ; the middle figure 

 a top view, a, head ; 6, cen- 

 trosome (?) ; c, middle piece ; 

 d, sheath about axial fibre (e). 



