chap, xvii.) THE COLON. 311 



reduction carefully watched. The diameter of the large 

 intestine (excluding the rectum) gradually diminishes 

 from the caecum to the sigmoid flexure, the diameter 

 of the former being about two and a half inches, of the 

 latter one and a half inches. The narrowest part of this 

 segment of the bowel is at the point of junction of the 

 sigmoid flexure with the rectum, and it is significant 

 that it is at this point that stricture is the most 

 common. 



The ccecum is said to be rudimentary in man and 

 in the carnivora. In herbivorous animals it is of 

 great size, and appears to serve as a reservoir for 

 the elaboration and absorption of food, since its 

 removal causes great emaciation. In man, therefore, 

 the caecum has been said to exist as an anatomical 

 protest against vegetarianism. The caecum is covered 

 in front, below, and at the sides with peritoneum, 

 the lower rounded end being completely invested, 

 while its posterior surface is connected by a great- 

 deal of loose areolar tissue with the iliac fascia. 

 It is in this loose tissue that inflammation spreads 

 in cases of perityphlitis, an inflammation that 

 usually originates in the caecum, and is often 

 due to a perforation on the posterior surface of that 

 part of the colon. The caecum when first developed 

 has an extensive mesentery. This condition may 

 sometimes be found in the fcetus at birth, and may 

 persist during life. The meso-caecum may be long 

 enough to allow the caecum to be herniated at the 

 umbilicus or even on the left side. 



Foreign bodies that have been swallowed are very 

 apt to lodge in the caecum, and to cause ulceration 

 and perforation of that bowel by their impaction. It 

 is significant that the otter has no caecum. This 

 animal lives largely on fish, and must swallow a 

 number of fish-bones. Had it a caecum it would pro- 

 bably soon fall a victim to perityphlitis and its effects. 



