SOCIETY OF THE UNIVERSITY OF ABERDEEN. H7 



looking downwards and to the right towards the ciccum, from which 

 it was distant about 2 inches. The free margin of this ring was 

 thickened and fibrous and stood out very distinctly as it arched 

 over the entering bowel. At the left margin the inferior mesenteric 

 artery came off the aorta and the left colic branch ran forward and 

 upward in the left cornu of the opening. The right cornu, with the 

 continuation of the left colic artery, arched over the bowel and then 

 ran upward for a distance of of inches to end at the duodeno-jejunal 

 flexure opposite the second lumbar vertebra. 



It so appeared that the opening of the peritoneal sac was displaced 

 by the weight of the contents from the second to the fourth lumbar 

 vertebra. The inferior mesenteric vein lay immediately to the left of 

 the opening. The whole of the small gut with the exception of the 

 lower 6 inches lay in a large hernial sac formed originally by 

 the fossa duodeno-jejunalis described by Treves and situated at the 

 commencement of the jejunum. This fossa, the orifice of which 

 looked upwards and to the left and formed by a delicate fold of 

 peritoneum passing from the beginning of the jejunum to the under 

 surface of the transverse meso-colon, was found in five out of ten 

 subjects. 



The size of the fossa is such that, as a rule, it scarcely admits the 

 tip of the little finger. In four of the cases in which it was present 

 the margin of the orifice was thin and delicate, but in one old female 

 subject the opening was bounded by a distinct ring, as in the case 

 described, which ended over the duodeno-jejunal flexure, the left cornu 

 formed by the left colic artery which ran in the margin and the right 

 by the commencement of the mesentery. 



In this case a fold of peritoneum passed from the duodeno-jejunal 

 junction to the under surface of the transverse meso-colon, bounding 

 a fossa which looked to the right but evidently quite apart from the 

 fossa into which the commencement of the jejunum would slip at 

 the first stage of the formation of the hernia, when the top of the 

 jejunum slips into the fossa and is followed from above downwards 

 by the rest of the small intestine. As the folds of peritoneum in this 



