THE TESTIS. 



517 



Fig. 246. 



The testis. 



vasculosum ; e, vasa efferentia ; y, 

 coni vasculosi ; <7, epididymis ; A, 

 vas deferens ; i, vas aberrans ; ?ft, 

 branches of the spermatica inter- 

 na of the testis and epididymis ; 

 w, ramification on the testis ; 0, ar- 

 teria deferentialis ; p, anastomosis 

 with a branch of the spermatic. 

 (Arnold.) 



The secretion of the testis must 

 be taken for examination from the 

 vas defe'rens or epididymis, before 

 it has been mixed with the fluid of 

 the prostate and Cowper's glands, 

 or with mucus. It may be min- 

 gled with a little albumen or se- 

 rum for the purpose of dilution, and, 

 when examined with a power of 

 500 diameters, exhibits multitudes 

 of moving bodies. These are the 

 seminal animalcules, or spermato- 

 zoa. Among them are to be seen, here and there, round granular bod- 

 ies, the seminal granules. These, with the spermatozoa, are sustained 

 in a clear and transparent liquid. The examination of these different 

 constituents is conducted with difficulty, since they can not be separated 

 from one another by means of filtration. The spermatozoa arise from 

 the seminal granules. 



The spermatozoa are found in the spermatic fluid of all animals after 

 puberty, their form being different in different classes and spermatozoa, 

 species. Generally they may be described' as consisting of description of. 

 a little oval-shaped head, from which a delicate filament or tail projects. 

 The motion of the spermatozoa is accomplished by means of their fil- 

 ament. It takes place in different ways, sometimes the filament vibrat- 

 ing like a whip, sometimes rotating like a screw, and sometimes a spin- 

 ning round, as it were, upon a pivot, occurs, the filament having been 

 coiled like a watch-spring. The rate of motion seems under the micro- 

 scope to be rapid ; it is, however, estimated at an inch in thirteen min- 

 utes. In man, their entire length may be estimated at about the -g-L of 

 an inch, the length of the head being about the 3^^, and its Human sper- 

 breadth the Io jj 00 . They continue to exhibit motion in matozoa - 

 birds for fifteen or twenty minutes after death ; in cold-blooded animals 

 even after days. They withstand, for a time, the action of solutions of 

 sugar and salt, but are destroyed at once by alcohol and dilute acids, 



