58 PROFESSOR A. BIRMINGHAM. 



difficulty. At the sides and below, the connection is much 

 looser. As a result, the peritoneum can, without much difficulty, 

 be stripped off the rectum in its lower third or half, whilst in 

 its upper portion this is not the case. This arrangement allows 

 of the free expansion of the lower part of the rectum (rectal 

 ampulla), without its being in any way hampered by its partial 

 peritoneal coat. 



The seminal vesicles, unless when of small size, slope 

 outwards and backwards around the front and sides of the 

 rectum, which they thus embrace, as it were, within their 

 grasp. 



Structure of the rectum. — The longitudinal muscular fibres, 

 although present all round, are chiefly accumulated on the front 

 and back of the tube, where they form two broad bands ; at the 

 sides they form a thinner layer, and the deepest of them are folded 

 in, and take part in the formation of the rectal valves in the 

 interior of the bowel. Where the rectum pierces the floor of the 

 pelvis, this layer appears to be united to the deeper portion of 

 the levator ani, partly by tendinous fibres and partly by an 

 interchange of muscular fibres between the levator ani and the 

 muscular coat of the rectum. (This interchange of fibres, how- 

 ever, is denied by Peter Thompson and Browning.) 



The mucous membrane of the rectum presents to the naked 

 eye a characteristic punctated appearance, which is due to the 

 presence of a considerable number of large round pits, such as 

 might be made by pressing a finely pointed pencil firmly against 

 the mucous membrane. I am not acquainted with any previous 

 description of these pits, which are, I believe, constant features 

 of the mucous membrane of the rectum. Each pit is lined by a 

 continuation of the mucous membrane provided with obliquely- 

 placed Lieberkilhn's glands, and in the mucosa at the 

 bottom of the pit is a mass of lymphoid tissue, the whole 

 appearance being such as might be produced were a solitary 

 gland pulled down from the svn^face into the substance of the 

 intestinal wall. 



Anal Canal. 



The anal canal, so well described by Symington, results from 

 the nipping in of the lower end of the bowel between the 



