194 PROFESSOR CHRISTOPHER ADDISON. 



his cases, and the fossa absent in 34 per cent. I have only 

 recorded the cases in which the fold was of any considerable 

 magnitude. There were only 5 of these cases, the best marked 

 being Nos. 19 and 27. Berry states that it is better marked in 

 the young. 



The fold passes as a rule from the anterior aspect of the peri- 

 toneum as it passes across the back abdominal wall towards the 

 ascending colon. It passes with its free concave border down- 

 wards and to the left, with the pouch directed upwards to the 

 right. (The direction of the pouch, however, in case 27 was 

 directly upwards.) 



The fold is caused by an anterior branch of the ileo-colic 

 artery passing on to the great bowel. Its attached margin on 

 the bowel is on the lower part of the ascending colon near the 

 ileo-colic junction, extending downwards on to the ctecum, or 

 it may be, as in case 19, on to the end of the ileum. The fossa 

 in cases 19 and 27 was 2 cm. deep and nearly 3 cm. wide at its 

 mouth. 



(2.) Ileo-Gcecal Fold (fig. 11, outline A). — This name of 

 Luschka's adopted by Lockwood and Eolleston aud Berry is better 

 than that of Treves — the bloodless fold. In most fat subjects 

 the fold contains a considerable quantity of fat — often loaded with 

 fat. Further, a small artery is occasionally found in the fold 

 which in some cases was a recurrent branch of the appendicular 

 artery. In 24 cases, or 60 per cent., the fold was very well 

 marked, producing more or less well-marked fossae in 23 of 

 them. I did not record the number of cases in which the fold 

 was completely absent, but they were certainly few. Berry 

 found it absent in 10 per cent, of cases, and the fossa in 26 per 

 cent. Treves considers this fold the representative of the true 

 meso-appendix. Jonnesco considers that the ileo-colic and ileo- 

 csecal folds, as they are here called, represent the mesenteries 

 of the caecum ; he does not regard the normal meso-appendix as 

 a substituted structure, as Treves suggests. The occasional 

 absence of the ileo-ctecal fold, whilst, he says, the meso-appendix 

 can be found represented even in the cases in which the appen- 

 dix is adherent to the back of the ca?cum, seems directed against 

 Treves' view. 



The cases mentioned in this paper, in which the appendix 



