282 REPORTS ON THE STATE OF SCIENCE, ETC. 



that they consist of twelve to twenty thin walled ducts which pass from the head ot 

 the testis to the caput epididymis. Observation in the dead animal showed that the 

 epididymis is connected to the testis by a membrane about J in. broad, which is 

 somewhat thickened where it terminates between the free extremity of the caput and 

 the head or anterior end of the testis. It seemed that this was the site of the vasa 

 efferentia indicated by Miss de Wagenen, and experiments were made to test the 

 effect of ligation of this thickened membrane, while at the same time microscopic 

 investigation was made to trace the vasa efferentia completely and certainly. 



In the first experiment the rat was killed three weeks after the operation and 

 sections of the testis showed complete disorganisation of the seminal epithelium in 

 the tubules. It seemed therefore that this was the actual position of the vasa 

 efferentia, but this is not the case. 



The vasa efferentia in the Rat. 



Shortly afterwards the number and course of the vasa in the rat were ascertained 

 by two methods, namely, by making cleared preparations of the whole membrane 

 containing them, from their origin from the testis to their junction with the caput 

 epididymis, and by making serial sections from the anterior end of the caput to the 

 portion of the testis containing the rete and the origin of the vasa. The number 

 of the vasa at their origin was found to be six, not twelve to twenty, as stated by 

 Miss de Wagenen, and at their origin from the rete they are straight. Farther on 

 they become more and more convoluted and form a bundle which increases in thick- 

 ness, passes dorsal to the epididymis, and joins the caput on its anterior border. The 

 inner end of the caput is, in fact, formed by a continuation of the bundle of the vasa 

 efferentia which bends back on itself and is continued into the body of the epididymis. 

 Where the vasa efferentia join the caput epididymis they are united into a single tube, 

 which is continued in a much convoluted but unbranched condition to form the whole 

 epididymis. 



It was afterwards found that these observations are in agreement with those of 

 Dr. Jacques Benoit, 1 of the Faculty of Medicine of Strasburg. Mr. Cunningham 

 also examined the corresponding parts in the mouse where the relations are very 

 similar. In the specimen examined, the number of vasa efferentia was only three ; 

 Benoit found four or five in the majority of cases, three in two specimens, and six 

 in one. 



The vasa efferentia in the rat leave the testis somewhat behind the anterior 

 extremity, near the point where the spermatic artery and vein enter it, and they pass 

 obliquely forward in the connecting membrane between the epididymis and testis. 

 The operation of ligaturing the vasa offered no great difficulty as they were not 

 closely connected with the vascular cord formed by the spermatic artery and vein. 



A number of experiments on ligation of the marginal membrane were made in 

 order to ascertain whether disorganisation of the seminal epithelium, as in the first 

 experiment mentioned above, was a constant result. The following is a list of these 

 experiments : — 



Experiments on ligation of marginal membrane. 



Marginal membrane in Rat ligatured on right side only. 



Post-operative 



period. Result. 



1. 21 days. Seminal epithelium disorganised. Weight of normal, left, testis 



2.5 gins., operated right, 1.3 gms. 



2. 14 days. Ligatured testis functional, but larger than the other. In sections 



a few tubules slightly abnormal, but the great majority showed 

 normal spermatogenesis. 



3. 7 days. Active spermatozoa in vas deferens of operated side. In sections 



of operated testis normal spermatogenesis, except in a few 

 tubules. 



1 Benoit, Dr. Jacques. ' Voies excretrices du testicule chez les Mammiferes. 

 Strasburg, Imp. Alsacienne, 1925. 



