306 THE ANATOMY OF THE HORSE. 



be prepared to find it deviating somewhat from the course just 

 described. 



The Double or Large Colon. This bowel is termed double because 

 when taken out of the abdomen it is arranged in the form of two paral- 

 lel portions ; but in order that it may be accommodated within the 

 cavity it has again to be doubled, so that in its natural disposition it 

 presents four portions, w T hich receive numerical designations. In an 

 animal of medium size its length is about ten feet, and its capacity 

 about sixteen gallons. It is puckered like the caecum, and from the 

 same cause. 



The 1st division of the bowel begins at the crook of the caecum, by 

 an orifice of communication which is comparatively small. It extends 

 downwards and forwards through the right hypochondriac region, bulg- 

 ing laterally into the umbilical region ; and on reaching the epigastrium 

 the bowel becomes bent on itself, forming what is termed, from its relation 

 to the ensiform cartilage of the sternum, the suprasternal flexure. The 

 angle of this flexure forms the point of separation between the 1st and 

 2nd portions of the double colon. 



The 2nd division, beginning at the suprasternal flexure, runs back- 

 wards on the left side of the abdomen, occupying the hypochondriac, 

 umbilical, and lumbar regions ; and, on approaching the entrance of the 

 pelvic cavity, the bowel forms in the iliac or hypogastric region a second 

 flexure — the pelvic flexure, the angle of which marks the point of separa- 

 tion between the 2nd and 3rd portions. The 1st and 2nd portions of the 

 double colon have extensive contact with the abdominal wall, and they 

 conceal the other two divisions of the bowel, which lie above them (in 

 the natural standing posture). 



The 3rd division, beginning at the pelvic flexure, extends forwards 

 along the left side of the abdomen, through the same areas as the 2nd 

 portion, being closely bound to it, and lying immediately above it. On 

 reaching the epigastric region a third flexure is formed, in contact with 

 the diaphragm, liver, and stomach, and from these relations named the 

 diaphragmatic or gastro-hepatic flexure. This will be brought into view 

 by grasping and pulling backwards the suprasternal flexure, above which 

 it lies. 



The 4th portion begins at the angle of the diaphragmatic flexure, and 

 passes backwards on the right side of the cavity, lying above the 1st 

 division, and closely bound to it. On reaching the inner side of the 

 crook of the caecum, to which it is adherent, it suddenly becomes much 

 reduced in calibre, and is continued as the small or floating colon. 



The pelvic flexure of the colon should now be seized and carried for- 

 wards, so as to place the bowel in the position shown in Plate 41. It 

 will now be observed that the bow r el is quite unattached except at its 

 beginning and termination, where it adheres to the pancreas and the 



