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the rectum we have an arrangement of its walls similar to that of the 

 colon, viz., that it is sacculated, with this difference only — in the rectum 

 we have two rows of sacculi, one on the left, the other on the right 

 side, while in the rest of the colon there are three rows of sacculi. 



In the colon it is well known that the sacculation of its walls is 

 due to the arrangement of the longitudinal muscular fibres into three 

 long flat bands, which when measured from end to end are shorter than 

 the parts intervening, and consequently cause a folding in of the walls 

 of the intestine between these bands. Tracing these three bands, or 

 ligaments of the colon, downward, the posterior band to which is attached 

 the mesentery can be seen as a distinct band along the posterior border 

 of the rectum, spreading out somewhat, laterally, and increasing in strength 

 in its lower part. The other two bands gradually approach each other 

 in the lower part of the colon, and finally unite at the commencement 

 of the rectum forming one broad band which passes down its anterior 

 border as such; while on the sides of the rectum the longitudinal muscu- 

 lar fibres are quite thin. Thus it will be seen that in the rectum we 

 have the longitudinal muscular fibres arranged in two groups, one on the 

 anterior border the other on the posterior border, which when measured 

 from end to end are shorter than the parts intervening, and cause by their 

 relative shortness a folding in of the lateral borders of the rectum at 

 various places, as is indicated by the constrictions seen on the sides ex- 

 ternally ; opposite these constrictions there is a corresponding projection 

 into the interior of the rectum, making the plicae which separate the 

 sacculi. 



At the places where the constrictions occur, the circular muscular 

 fibres are accumulated into quite thick bundles, forming a ridge somewhat 

 prismatic in shape, appearing as though drawn together by the action of 

 the longitudinal muscular fibres, and at the same time puckering up the 

 mucous membrane into a deep fold directly over it, projecting into the 

 lumen of the gut from 1 — 2,5 cm. It is these folds, which for the most 

 part are meerly a duplication of mucous membrane, that you will see on 

 looking into the rectum of this body which I have placed in the knee- 

 elbow position, care having been taken to have no pressure upon the 

 abdomen. For illuminating the rectum I use, at first, reflected light from 

 a head mirror, which leaves both hands free for manipulation, to open 

 up the rectum so as to allow the air to enter; after the pneumatic dila- 

 tation has taken place I then use this small electric light which I can 

 introduce into the rectum and carry to any point desired, producing as 

 you will see, a most beautiful illumination. 



The number of these plicae that can be seen by this method of 

 inspection are generally three, sometimes four, but in this case there are 

 five. The first, that nearest the anus, is on the left, the second is a 

 little higher on the right, and is the "plica transversal! s" of Kohl- 

 rausch, which marks in a general way the lowest point to which the 

 recto-vesical pouch of peritoneum reaches, the third is still higher on the 

 left, and so on. If we could see the whole length of the rectum, we 

 would see that this arrangement extends through out its entire course, 



