472 Eben Clayton Hill. 



mammals including man. On one point he has not laid especial 

 emphasis, and that is the great strength of the reticulum of the testes 

 of man and its resistant powers. 



Testes treated with weak KOH do not macerate readily, and even 

 after the capsule has become disintegrated the tubules are firm and 

 resistant. They are elastic and can be teased out of their full 

 length without breaking. This is due to the great amount of reti- 

 culum surrounding them (Fig. 6). A similar reticular structure is 

 found in the tubules of the kidney (Mall), only the reticulum of the 

 testis is denser. It is the presence of this large amount of reticulum 

 that prevents the preparation of specimens of the gross structure of 

 the lobular arrangement of the spleen which Professor Mall found 

 of such value in studying that organ. 



Turning again to the description of vessels we find that the com- 

 paratively large branches given off at the mediastinum divide into 

 many small branches which radiate toward the albuginea like spokes 

 in a wheel. These ascending arteries (A A, Fig. 1) pass between 

 the lobules and give off capillary branches to the tubules. An 

 anastomosis may be noted between the ascending arteries and the 

 descending arteries (D. A., Fig. 7) given off from the capsular 

 arteries and their branches. The veins follow the general course 

 of the arteries. There are several large capsular veins which en- 

 circle the gland, lying on the inner side of the capsule and empty- 

 ing into the pampiniform plexus. These capsular veins "receive 

 blood from the capillaries and veins on the inner surface of the 

 tunica albuginea, from the tunica vaginalis visceralis and from 

 anastomoses with the ascending veins which enclose the lobule 

 (A. v.. Fig. 7). The blood is also returned to the pampiniform 

 plexus by descending veins which follow the course of the arteries 

 and empty into the venous plexus at the mediastinum (D. V., 

 Fig- T). .' 



Fig. 7. — Sagittal section of human testis ; to show blood supply. Injected 

 with red and blue celloidin, cleared in 1 per cent KOH and 20 per cent 

 glycerine, x 4. 



A. A., ascending artery ; A. V., ascending vein ; D. A., descending artery ; 

 D. v., descending vein ; M., mediastinum ; Y. D.. vas deferens ; T. A., tunica 

 albuginea ; T. P., tunica parietalis. 



