n8 PRACTICAL HISTOLOGY. 



THE LYMPHATICS OF THE TESTIS. 



PREPARATION. Thrust the nozzle of a syringe into a perfectly fresh testicle, and inject 

 into its substance a two per cent, watery solution of Berlin-blue. The lymphatics in the tunica 

 albuginea and spermatic cord are rapidly filled. Harden the testis in alcohol, and make sec- 

 tions, which are to be stained with picrocarmine and mounted in dammar, or in Farrant's solu- 

 tion. The blue colouring matter passes into the origin of the lymphatics between the tubes, 

 but none of it passes into them. 



EXAMINATION (L and H). Observe the seminal tubules, stained of a yellowish-red 

 colour, and between them note the distribution of the blue colouring matter, which has passed 

 into the lymphatics. 



THE SPERMATOZOA. 



(A.) IN THE LIVING CONDITION. 



1. PREPARATION in the Newt. Kill a large male newt (Triton cristatus), which may be 

 readily recognised by the serrated crest along its back. Remove the viscera, when the testes 

 two or three on each side will be found as small round bodies, lying close to the spinal 

 column. Remove one of these, make a cut into it, and press out a little of its milky contents 

 on to a slide, add a drop of salt solution ; cover and examine. 



EXAMINATION (H). Observe the seething mass of spermatozoa. Each one consists of 

 a so-called head, to which is attached a long, curved prolongation, the tail or filament. Study 

 one, and note that the tail moves with a rapid lashing motion, not unlike the action of a 

 cilium, with the result of propelling onwards the spermatozoon. 



It is well to examine these spermatozoa with a higher power, with a lens of at least -inch 

 focal distance. Each spermatozoon is then seen to consist of a head, and next to it is the 

 middle piece of Schweigger-Seidel, and attached to this is the long, pointed filament or tail. 

 A long spiral filament is attached to this by a very transparent membrane (Leydig, H. 

 Gibbes). 



2. In a Mammal,^, a Sheep. Make a cut into the globus major of a perfectly fresh testicle, 

 and press out a little of the milky seminal fluid, and examine it as above. 



(B.) PERMANENT PREPARATIONS. 



1. Spermatozoa of the Newt. Harden the testis of a newt in five per cent, ammonium 

 chromate for twenty-four hours ; wash away all the colouring matter, and divide a testis, and 

 then press out a little of the fluid, which is next mixed with a drop of glycerine, covered and 

 preserved in the ordinary way. The spermatozoa of a newt may be stained with logwood and 

 an aniline dye, but the process is rather difficult, and requires much time and practice. 



2. Mammalian Spermatozoa, (a) Place a little glycerine in a watch-glass, and add to it a 

 few drops of absolute alcohol. Make a cut into the globus major of a perfectly fresh testis. 

 Press out some of the fluid into the watch-glass, and mix it thoroughly with the glycerine 

 fluid. Place a drop of this on a slide, and cover (PL XXVIII., Fig. 5). 



(If) Another way is to place a drop of seminal fluid on a slide and allow it to dry,andthen 

 cover and seal it up dry, without the addition of any fluid. 



