202 PROFESSOR CHRISTOPHER ADDISON. 



or, by its absence, allowing the meso-sigmoid to become 

 straightened out. 



The commonest variation of the meso-sigmoid is the oblitera- 

 tion, either by adhesions or by bowel growth, of its upper or 

 outer limb (see case 18, fig. 12), leaving the inner portion 

 V-shaped, with the apex of the V upwards. 



The presence of both limbs of the meso-sigmoid or the 

 absence of the outer limb in this series of cases occurred with 

 the following frequency : — 



Absence of the outer limb in 11 cases, or 27"5 per cent. 



Presence of both limbs, more or less well marked, in 27 cases, 

 or 67 '5 per cent. Absence of a meso-sigmoid of either of these 

 types in the presence of a complete descending meso-colon 

 occurred in 2 cases, or 5 per cent. 



Including those cases in which there was absence of the outer 

 limb of the meso-sigmoid, there ivere peritoneal bands or 

 adhesions rendering the 'portion of the sigmoid colon up to the 

 brim of the pelvis more or less immovable in 24 cases, or 60 ^^er 

 cent, of the series. 



Inter-Sigmoid Pouch. — There were several cases in which a 

 well-marked pit existed under cover of the meso-sigmoid at 

 its summit ; but there were only 5 cases — Nos. 12, 14, 27, 

 32, and 34 — in which a distinct pouch extended upwards 

 beneath the layers of the meso-sigmoid. Case 27 presented 

 the largest example. 



In the averages on Table VI. (p. 188) of the point of the 

 commencement of the meso-sigmoid, those cases are included 

 in which the outer limb was absent. If these be excluded, 

 the plane CD. as the level of the commencement of the meso- 

 sigmoid is remarkably regular, the average for the cases pre- 

 senting both limbs of the meso-sigmoid being "4 cm. above. 



In two cases — Nos. 23 and 27 — peritoneal poelxcts sufficient to 

 admit the finger existed in the left iliac fossa, passing behind 

 the bowel from the outside. 



On fig. 12, No. 18, a well-marked Idnk of the descending colon 

 is shown in a pocket behind the outer border of the psoas 

 muscle at the upper part of the iliac fossa. The bowel was 

 tightly bound in this pocket by the peritoneum. A similar 

 condition existed in cases 9 and 13, The outer border of the 



