1'38 



HEALTH AND DISEASE 



The colon is divisible into two parts — the large or double colon, and 

 the small or floating colon. The length of the large colon is about 12 feet, 

 and its capacity about 18 gallons. The length of the small colon is about 



10 feet. The caecum and 



\ \ / " both the large and small 



\ V? i colon have the same general 



y---~' | ' arrangement of the coats 



as the other parts of the 



intestine. 



The rectum is a 

 short, straight tube ex- 

 tending from the last and 

 shortest division of the 

 colon. It takes a straight 

 course backward, and ter- 

 minates in the anus or 

 external orifice. The mus- 

 cular layer of this segment 

 of the intestine is very 

 strongly developed. The 

 orifice is surrounded by 

 circular fibres, which form 

 a tolerably well - defined 

 ring to which the name 

 of sphincter ani has been 

 given. This ring keeps the 

 aperture closed. There is 

 also another muscle con- 

 nected with it, which pulls 

 the posterior part of the 

 bowel forward after de- 

 fecation, and is known as 

 the retractor ani. 



The liver.— This or- 

 gan is the largest gland in 

 the body, weighing from 

 10 to 12 lbs. avoirdupois. It occupies the fore part and right side of the 

 abdominal cavity, being situated immediately behind the diaphragm. It 

 is kept in position by strong folds of the peritoneum, which extend from 

 it to the diaphragm and adjoining organs. Its colour is reddish-brown. 

 It is divisible into three principal lobes, of which the left is the largest 



Fig. 87.— Large Intestine, showing its Position i 

 For description see Fig. SO. 



