106 



ANATOMY AND PHYSIOLOGY OP 



being remarkably more developed in soli- 

 pedes than in any other of our domestic 

 quadrupeds. It occupies the greater part 

 of the abdomen, and most of it is loose, 

 whilst its shape and other peculiarities vary 

 considerably at diflerent points. 



It is divided into three parts — caecum, 

 colon, and rectum — the precise extent of 

 each being defined by special anatomical 

 characters. 



The position of the large intestine being 

 constant, it is necessary, for sake of pre- 

 cision, to speak of the whole as to the 

 course it takes in forming the three divis- 

 ions, extending thus betw^een the small 

 intestine and anus. 



The cascum, or blind pouch, is the first 

 gut, which protrudes in the middle on cut- 

 ting through the abdominal walls at the 

 linea alba. Its bend or blind extremity is 

 projecting into the left hypochondiiac 

 region ; its body crosses obliquely the floor 

 of the abdomen, to reach the right iliac 

 region, where it suddenly bends at an acute 

 angle, being rather constricted, and forms 

 the colon. At this part the latter receives 

 the ileum, and extends up the right side of 

 the abdomen to the diaphragm, where it 

 traverses the direction of the spine, resting on 

 the ensiform cartilage ; turning round the left 

 side, it attains the left iliac fossa posteriorly, 

 where it forms a twist like a letter S, from 

 which similitude it has been termed the Sig- 

 moid Flexure of the Colon. The gut, 

 having diminished in size, returns up the 

 same side of the abdomen to the diaphragm, 

 where it again crosses the spine. Being 

 now on the right side, it continues back 

 to a point beyond the anterior mesenteric 

 artery, where it turns upward and for- 

 ward, so as to come in front of the artery 

 in question ; then, from right to left, so as 

 to cross the spine for the third time, consti- 

 tuting the transverse colon, which is more 

 capacious than the part preceding it. The 

 two curves which it forms, one on the right 

 and the other on the left, are respectively 

 called the hepatic and gastric flexures of 

 the colon. The gut so proceeds backward 

 along the left side of the mesentery, being 



diminished again in size, and constituting 

 the single colon, till we get to the posterior 

 mesentery artery, where, unaltered in other 

 respects, it takes a straight course through 

 the pelvis, out at the anus, and hence the 

 name of Rectum. 



The csBum, so called from having only 

 one outlet, being closed at its anterior part, 

 or caecum caput coli, from its being the 

 blind head of the colon, is vulgarly termed 

 the water-bag, owing to the almost invari- 

 able fluidity of its contents. 



It is situated, as I have before said, ob- 

 liquely along the floor of the abdomen, ex- 

 tending backwards from left to right. 



It is attached to the spine by a meso- 

 cseum, which is a fold of peritoneum, com- 

 ing off from the spine on to the superior 

 part of the pouch. There is then the fold 

 already alluded to, which stretches from the 

 ileum on to the csecum, and, through the 

 medium of the mesentery, indirectly con- 

 necting the latter with the spine. 



The caecum is cone-shaped, having an 

 apex and a broad base. The former gene- 

 rally protrudes the first, when a medium 

 longitudinal incision is made into the 

 abdominal walls, although it is situated 

 above the left portion of the double colon, 

 whilst the liver is directly in contact wdth 

 the floor of the abdomen. Like the other 

 divisions of the large intestine, the caecum 

 is sacculated. The bands producing this 

 appearance are three in number at the 

 apex ; but between two and three inches 

 from this, one of them bifurcates, so that 

 four bands result, which are continuous on 

 to the colon. 



The colon arising from the caecum, re- 

 ceives at first the contents of the ileum, 

 being situated along and occupying the 

 greater part of the floor of the abdomen. 



The colon is generally distinguished as 

 double and single. By double, is meant 

 the flexures of the gut from its commence- 

 ment to its gastric cm-ve ; whilst by the 

 single colon, is understood the continuation 

 of the same intestine to the part where the 

 rectum commences. 



The double colon is attached by the peri- 



