THE VISCERA OF THE ABDOMEN, OR BELLY. 65 



When the animal Is in a standing posture, the lower part of 

 the abdomen is occupied by the large intestines; the apex of the 

 Cfficum being about the centre, and the colon around it : above 

 them are the small intestines, which, however, sometimes in- 

 sinuate between the large. 



The most important of the abdominal viscera is the stomach, 

 which in the horse is of a peculiar structure, and considerably 

 smaller than in any other animal of similar bulk and power. It 

 is a strong muscular cavity, capable of considerable distention, 

 as has been found on opening horses that have died of stomach 

 staggers, in which disorder it has been stretched to a most 

 enormous extent. In one instance I have known the stomach, 

 with the hardened undigested food it contained, weigh more 

 than sixty pounds. Sometimes it is distended with air to a 

 considerable degi-ee, as in indigestion or flatulent colic : but in 

 the healthy state it is comparatively small, and of great 

 strength. 



The stomach is situated on the left side, with its convex part 

 against the diaphragm ; it has the spleen attached to its left ex- 

 tremity, and its lower j)art is covered with the omentum or 

 caul. When the stomach is full, its situation so close to the 

 diaphragm will sufficiently account for the fact that, after being 

 loaded, the horse is incapable of great exertion, and respiration 

 becomes disturbed : the action of the diaphragm becomes indeed 

 mechanically impeded. 



The stomach possesses four coats. The first is formed by the 

 peritoneum ; the second, situated next to the first, is, like the 

 former, white, and is composed of two sets of muscular fibres ; 

 one set running in a longitudinal direction, and the other in a 

 circular course ; the latter are stronger than the former, and are 

 situated within them. 



The third and fourth coats line the interior of the stomach. 

 On turning this viscus inside out, we find one half occupied by 

 a Avhite, cuticular, and almost insensible membrane, separated 

 from the fourth coat by a waving line. It extends over the left 

 extremity, and its elasticity enables it to accommodate itself to 

 the varying size of the stomach. The fourth coat, called the 

 villous or mucous, lines the larger half of the stomach. It is 

 somewhat red or yellow in its colour, is very vascular and sen- 

 sible, and exhibits numerous processes, having the appearance 

 of velvet, which are indeea the minute ramifications of blood 

 vessels, by which a most important fluid is secreted, called the 

 gastric juice. 



The stomach has two extremities, the right and the left ; the 

 latter of which is the larger, and terminates in a sort of pouch. 



It has also two curvatures, a large and a small one : to the 

 former the omentum and spleen are attached. It possesses two 



