THE GENERATIVE ORGANS. 193 



The movements of the living spermatozoa may be 

 studied by mixing some of the milky fluid from the epi- 

 didymis of a freshly killed animal, on a warm slide, with 

 |-per-cent. salt solution, and protecting from pressure 

 by a hair. 



The temperature of the slide should be kept at about 

 the same elevation as that of the animal from which they 

 are taken. The movement may be stopped by the ad- 

 dition of water. 



Sections of the Testicle. A human testicle, obtained as 

 soon as possible after death, or, if this cannot be ob- 

 tained, a testicle of the cat, rabbit, or dog is hardened in 

 alcohol. The organ is then imbedded in celloidin and 

 transverse sections made through the entire organ at the 

 upper part of its middle third. These are to be stained 

 double and mounted in balsam. Sections made, as 

 above, show the seminiferous tubules cut in various di- 

 rections ; the rete testis ; the tubules of the epididymis 

 also cut in various directions, held together by loose con- 

 nective tissue, and lined with cylindrical ciliated epi- 

 thelial cells, the lumen of the tubules being filled with 

 spermatozoa and granular material. The vas deferens is 

 shown in transverse section ; its periphery being sur- 

 rounded with loose connective tissue, which binds it to 

 adjacent parts. Internally it is lined with mucous mem- 

 brane, generally thrown up into irregular longitudinal 

 folds, the free surface of which is covered with cylindri- 

 cal epithelium. Externally to the mucous membrane is 

 the muscular coat, consisting of two layers of smooth 

 muscle tissue, an outer longitudinal and an inner circular 

 layer. 

 13 



