408 



ception to some extent may occur, need not be doubted but, if so, 

 they must be rare, and such an occurrence cannot be allowed to 

 excuse the serious error of describing the caecum as usually uncovered 

 by peritoneum behind". 



With regard to the rarity of the exceptions to the complete 

 peritoneal investment of the caecum, Tuffier (14) says that in 

 120 bodies, upon nine occasions he found the caecum devoid of peri- 

 toneum posteriorly: in all the other cases it was completely surroun- 

 ded by peritoneum. 



JoNNESco [(lb) one of the most recent authors agrees, in the 

 main, with Bardeleben and Luschka that "we cannot perforate the 

 caecum without first traversing the visceral serous layer which sur- 

 rounds it on all sides: the organ is free within the abdominal cavity. 

 This is the rule, the contrary is a rare exception or a pathological 

 condition". 



On analysing my own series of cases I find, that so far from 

 the peritoneum being deficient upon the posterior surface that the 

 viscus is surrounded by peritoneum on every side in 94^0 of cases. 



One of the cases, where the caecum was not so surrounded, is 

 extremely interesting as the patient died from a non-diagnosed appen- 

 dicitis, the abscess pointing in the abdominal wall. 



Conclusions. 



The superior border of the caecum , or the level of the ileo- 

 caecal valve corresponds externally to the fraenal furrows of 

 Struthers. When these are absent, the upper level of the caecum can 

 only be taken approximately on a line drawn transversely across the 

 large intestine from a point midway between the upper and lower 

 borders of the ileum : — all caecal measurements should be made from 

 the "furrows" (Struthers) or the approximate line (Berry). 



The average dimensions of the caecum are 6,0 cm in length, and 

 7,0 cm in breadth, these diameters are never equal in length and 

 bear no relation to sex. The size of the caecum varies with age, 

 being larger absolutely and relatively in the adult than in the child, 

 whilst lastly the caeca of insane persons would often appear to show 

 some abnormality in size, shape or appearance. 



The third type of caecum occurs in about 90 7o of all adult 

 cases, a fact of great importance to the surgeon as it simplifies the 

 location of the appendix during the performance of an appendicectomy. 



Lastly the caecum is surrounded and invested by peritoneum in 

 94 % of cases ; a meso-caecum is non-existent. 



