The Vascularization of the Human Testis. 469 



branch is given off from the spermatic artery which anastomoses 

 with the artery supplying the vas deferens (C, Fig. 1). 



The blood supply of the tunica vaginalis parietalis (Fig. 2) is 

 uninteresting. The arteries pass to this tunic near the epididymis, 

 are slightly tortuous, give out small branches, which ending in capil- 

 laries, form a plexus. The blood from this plexus is collected 

 into veins which in turn empty near the epididymis. 



The blood supply of the tunica albuginea and the branches given 

 off from the capsular arteries is shown. in Fig. 3. A thick section, 

 including the albuginea and a portion of the glandular substance, 

 taken from an inject'ed gland and cleared, shows three general group- 

 ings of vessels: — 



First (A), those dipping perpendicularly into the glandular sub- 

 stance and following the trabeculae to supply the lobules. 



Second (B), capsular arteries and their branches on the inner side 

 of the tunica albuginea, and 



Third (C), the small branches given oft" from the capsular ar- 

 teries which pass outward and penetrate the albuginea supplying it 

 and the tunica vaginalis visceralis. 



Corrosion specimens of the human testis show very clearly the 

 arrangement of the vessels, and these, when placed in glycerine, 

 may be isolated in order to study their characteristics. (Fig. 4.) 



In this connection it may be of interest from the standpoint of 

 comparative anatomy to note the marked differences • between the 

 blood supply of the testis of the pig and that of man. This is 

 especially well shown by isolating arteries from corrosion specimens 

 of each. In man the distribution of these vessels and their course 



Fig. 2— Blood supply of tunica parietalis of the liuuian testis. Injected 

 with India ink under 20 mm. Hg. pressure. Drawn with camera lucida. 

 X 26%. A., artery; V., vein. 



Fig. 3. — Celloidin arterial injection of capsule and outermost glandular 

 tissue of human adult testis. Specimen cleared in 1 per cent KOH and 

 glycerin. Three arrangements of vessels are shown. 1st. Surface vessels 

 on outer side of tunica albuginea. (c) These arise from branches of capsular 

 arteries (b) which lie on inner side of albuginea. From these latter vessels 

 branches (a) penetrate the glandular tissue and anastomose with the as- 

 cending arteries coming from the mediastinum. X 10. 



