The Vascularization of the Unman Testis. 467 



Hnschke as to the comparative size of the renal artery and sper- 

 matic vessels. Huschke states that the calibre of the renal artery 

 is 15 times that of the internal spermatic artery, although the 

 weight of the testis is only one-eighth as great as that of the 

 kidney. This is a most interesting observation and explains the 

 difficulty met with in attempting injections of the testis. ISTot only 

 is the spermatic artery very small, but it is long and near the 

 human sex gland becomes tortuous, although this is hardly appre- 

 ciable as compared to the great tortuosity met with in the spermatic 

 artery of the pig. Arnold in describing the veins states that these 

 veins "entsprechen in ihrer Anordnung im Allgemeinen den Ar- 

 terien." He traces the blood from the testis through the pampino- 

 form plexus and its subsequent branches back into the renal vein 

 or aorta. Thus it is seen that he does not trace the blood farther 

 than to the gland itself, and makes no attempt at interpreting its 

 course after reaching the mediastinum or albuginea. 



That he should have been in doubt about the distribution of the 

 arterial supply near the mediastinum is easily understood because 

 only the most perfect double injection made by methods but re- 

 cently developed, could aid in unravelling the profusion of veins 

 and arteries at this portion of the gland. Astley Cooper has in- 

 vestigated a capillary plexus covering the inner surface of the 

 tunica albuginea, which he has termed the tunica vasculosa. 



Aside from these valuable contributions, practically no work 

 has been done on the blood supply of the testis ; hence the following 

 results seem worthy of record. 



The spermatic artery arises from the abnormal aorta as a long 

 slender branch passing into the abdominal rings, and from here 

 follows in the spermatic cord to the testis. The vessel which 

 directly supplies the testis proper and which is a direct continua- 

 tion of the spermatic artery has been named by Arnold the in- 

 ternal spermatic artery. The spermatic artery, before giving off 

 its terminal branch or branches to the testis, gives off ordinarily a 

 branch, the external spermatic artery, high in the cord, just below 

 the external abdominal ring which in time divides in two or more 

 branches to supply the membranes of the testis. Until the sper- 



