THE TESTE8. 1021 



have walls of considerable thickness, on account of the presence in them of mus- 

 cular tissue, which is principally arranged in a circular manner. These tubes are 

 lined by columnar ciliated epithelium. 



The Vas Deferens, the excretory duct of the testis, is the continuation of the 

 epididymis. Commencing at the lower part of the globus minor, it ascends along 

 the posterior border of the testis and inner side of the epididymis, and along the 

 back part of the spermatic cord, through the inguinal canal to the internal or 

 deep abdominal ring. From the ring it curves round the outer side of the epi- 

 gastric artery, crosses the external iliac vessels, and descends into the pelvis at 

 the side of the bladder ; it arches backward and downward to its base, crossing 

 over the obliterated hypogastric artery and to the inner side of the ureter. At the 

 base of the bladder it lies between that viscus and the rectum, running along the 

 inner border of the vesicula seminalis. In this situation it becomes enlarged and 

 sacculated, forming the ampulla, and then, becoming narrowed at the base of the 

 prostate, unites with the duct of the vesicula seminalis to form the ejaculatory 

 duct. The vas deferens presents a hard and cord-like sensation to the fingers ; it 

 is about two feet in length, of cylindrical form, and about a line and a quarter in 

 diameter. Its walls are dense, measuring one- third of a line, and its canal is 

 extremely small, measuring about half a line. 



Structure. The vas deferens consists of three coats : 1. An external or areolar 

 coat. 2. A muscular coat, which in the greater part of the tube consists of two 

 layers of unstriped muscular fibre : an outer, longitudinal in direction, and an 

 inner, circular ; but in addition to these, at the commencement of the vas deferens, 

 there is a third layer, consisting of longitudinal fibres, placed internal to the circular 

 stratum, between it and the mucous membrane. 3. An internal or mucous coat, 

 which is pale, and arranged in longitudinal folds ; its epithelial covering is of the 

 columnar variety. 



A long narrow tube, the vas aberrans of Haller, is occasionally found connected 

 with the lower part of the canal of the epididymis or with the commencement of 

 the vas deferens. It extends up into the cord for about two or three inches, where 

 it terminates by a blind extremity, which is occasionally bifurcated. Its length 

 varies from an inch and a half to fourteen inches, and sometimes it becomes dilated 

 toward its extremity ; more commonly it retains the same diameter throughout. 

 Its structure is similar to that of the vas deferens. Occasionally it is found uncon- 

 nected with the epididymis. 



Organ of Giraldes. This term is applied to a small collection of convoluted 

 tubules, situated in front of the lower part of the cord or above the globus major 

 of the epididymis. These tubes are lined with columnar ciliated epithelium, and 

 probably represent the remains of a part of the Wolffian body. 



Surgical Anatomy. The testicle frequently requires removal for malignant disease ; in 

 tuberculous disease ; in cystic disease ; in cases of large hernia testis, and in some instances of 

 incompletely descended or misplaced testicles. The operation of castration has also been, during 

 the last few years, performed for enlargement of the prostate ; for it has been found that removal 

 of the testicle is followed by very rapid and often considerable diminution in the size of the 

 prostate. The operation is, however, one of severity, and is frequently followed by death in 

 these cases, performed, as it necessarily is, in old men. Reginald Harrison has proposed to sub- 

 stitute for it excision of a portion of the vasa deferentia. The operation of castration is a com- 

 paratively simple one. An incision is made into the tunica vaginalis from the external ring to 

 the bottom of the scrotum. The coverings are shelled off the organ, and the mesorchium, 

 stretching between the back of the testicle and the scrotum, divided. The cord is then isolated, 

 and an aneurism needle, armed with a double ligature, passed under it, as high as is thought 

 necessary, and the cord tied in two places, and divided between the ligatures. Sometimes, in 

 cases of malignant disease, it is desirable to open the inguinal canal and tie the cord as near the 

 internal abdominal ring as possible. 



Spermatozoa. The spermatozoa are minute, thread-like bodies, which constitute 

 the essential elements of the semen. Each consists of a head, a middle piece or 

 body, and an elongated filament or tail. The head, on surface view, appears oval in 

 shape, but if seen in profile it is narrow and pointed at its free end. It represents 



