abdominal viscera in man. 199 



Ascending or Descending Meso- Colon. 



There were 6 cases, or 15 per cent., presenting an ascending 

 meso-colon, and 9 cases, or 22 per cent., with a descending meso- 

 colon. Two cases were common to the two groups — viz., cases 

 8 and 19. 



The other examples of an ascending meso-colon were in 

 cases 18, 31, 34, and 38; and of a descending meso-colon, in 

 cases 1, 14, 15, 23, 26, 32, and 37. In Treves's (15) series of 

 100 cases the percentage showing the existence of these folds 

 is placed higher — namely, of an ascending meso-colon 28 per 

 cent., and of a descending meso-colon 36 per cent. 



There were other cases of this series in which, with a very 

 little dragging on the colon, one could have produced a meso- 

 colon more or less complete, and for surgical purposes it would 

 have been, perhaps, as good as existent. I have, however, only 

 described as meso-colons those in which the layers of peritoneum 

 passing to the bowel were in contact without manipulation. 



Ascending Meso-Colon. — In case 19 the ascending meso-colon 

 only extended upwards for 2*5 cm. above the iliac crest. In case 

 31 it was short and evidently had been produced by enormous 

 distension of the ascending colon. In case 34 it only reached 

 up to the iliac crest, where the inner layer passed inwards into 

 a low transverse meso-colon. Cases 8, 18, and 38 were excel- 

 lent examples of an ascending meso-colon. In all of them it is 

 important to note that a long free appendix passed upwards 

 behind the colon, external to the meso-colon. The distance of 

 the attachment of the meso-colon from the middle line was that 

 of the average position of the peritoneal reflection on to the 

 inner side of the ascending colon — viz., 7 to 7" 5 cm. 



The Descending Meso-Colon. — In cases 1, 18, and 19 the line of 

 the normal reflection of the peritoneum on to the inner side of 

 the descending colon was pursued by an uninterrupted mesentery 

 down to the iliac crest, where there was an interruption of 5 

 cm. or more before the meso-sigmoid commenced. The same 

 applies to cases 14 and 15, except that in them the meso-colon 

 did not reach quite down to the iliac crest. In case 37 the 

 meso-colon was short, evidently produced secondarily by great 

 bowel distension, and reached down to CD., after which there 



