VESICULJ3 SEMINALES. 



533 



rectum, through which it may be distinctly felt. It surrounds the 

 commencement of the urethra for a little more than an inch of its 

 extent, and resembles a Spanish chestnut both in size and form ; the 

 base being directed backwards towards the neck of the bladder, the 

 apex forwards, and the convex side towards the rectum. It is re- 

 tained firmly in its position by the two superior, and the two inferior 

 tendons of the bladder, by the attachments of the pelvic fascia, and 

 by$a process of the internal layer of the deep perineal fascia, which 

 forms a sheath around the membranous urethra, and is inserted into 

 the apex of the gland. It consists of three lobes, two lateral and a 

 middle lobe or isthmus ; the lateral lobes are distinguished by an in- 

 dentation upon the base of the gland, and by a slight furrow upon 

 its upper and lower surface. The third lobe or isthmus is a small 

 transverse band which passes between the two lateral lobes at the 

 base of the organ. In structure the prostate gland is composed of 

 ramified ducts, terminating in lobules of follicular. pouches which 

 are so closely compressed as to give to a thin section of the gland a 

 cellular appearance beneath the microscope. It is pale in colour 

 and hard in texture, splits easily, in the course of its ducts, and is 

 surrounded by a plexus of veins which are enclosed by the strong 

 fibrous membrane with which it is invested. Its secretion is poured 

 into the prostatic portion of the urethra by fifteen or twenty excre- 

 tory ducts. The urethra in passing through the prostate lies one 

 third nearer to its upper than to its lower surface. 



Fig. 159 * 



VESICUL.S SEMINALES. 



Upon the under surface of the base of the bladder, and converging 

 towards the base of the prostate gland, 

 are two lobulated and somewhat pyriform 

 bodies, about two inches in length, the vesi- 

 cuke seminales. Their upper surface is in 

 contact with the base of the bladder ; the 

 under side rests upon the rectum, separated 

 only by the recto- vesical fascia ; the larger 

 extremities are directed backwards and 

 outwards, and the smaller ends almost meet 

 at the base of the prostate. They enclose 

 between them a triangular space, which is 

 bounded posteriorly by the recto-vesical fold 

 of peritoneum; and which corresponds with 

 the trigonum vesicge on the interior of the 

 bladder. Each vesicula is formed by the 

 convolutions of a single tube, which gives 

 off several irregular caocal branches. It is 



* The posterior aspect of the male bladder ; the serous covering is removed in order 

 to show tho muscular coat. 1. The body of the bladder. 2. Its fundus. 3. Its inferior 

 fundus or base. 4. The urachus. 5, 5, The ureters. 6, 6. The vasa deferentia. 7, 

 7. The vesiculae seminales. The triangular area, corresponding with the trigonum 

 vesicac through which the bladder would be pierced, in puncturing the bladder through 

 the rectum. The dotted line forming the base of this triangular area, marks the ex- 

 tent of the recto- vesical fold of the peritoneum. 



