THE ANATOMY OF THE HORSE. 31 



The Gullet is a cavity situated just behind the mouth. It is 

 chiefly made up of muscles which perform the act of swallowing" 

 the food. It is lined with the continuation of the mucous mem- 

 brane oi' the mouth. 



The Oesophagus, or the continuation of the gullet, which is a 

 tube extendins^ from the gullet to the stomach, is used to carry the 

 food to that organ. It is made up of two coats, the muscular 

 and the mucous. The former contains fibres which, when once 

 the food enters the tube, contracts behind it, forcing it along to 

 the stomach. Its lining is a continuation of the mucous membrane 

 of the mouth and "gullet. In tracing the tube down the neck from 

 the gullet, it passes down the left side of the neck, entering the 

 thoracic, or chest cavity, between the lungs over the heart through 

 the large muscular curtain known as the diaphragm, entering the 

 stomach an inch or two after passing the diaphragm. 



The Stomach. — This organ is very small in the horse in com- 

 parison with the ox ; it only holds about four gallons, and is 

 situated just behind the curtain which separates it from the lungs ; 

 it is mostly to the left side. The walls of the stomach are composed 

 of three coats, one on the outside called the serous membrane — 

 this is a name applied to membranes which line closed cavities, 

 such as the abdominal, or belly cavity. The inside lining is a 

 continuation of the m.ucous membrane lining the organs before 

 mentioned. When the stomach is empty this membrane is thrown 

 into loose folds, and there are also found several small openings 

 through which the gastric juice and pepsine from the glands, 

 situated in the walls of the stomach, enters. These are very 

 important fluids as they assist greatly in digesting the food. The 

 third coat is known as the muscular coat, being made of 

 muscular fibres, and is situated between the two coats already 

 mentioned. Its action is to give the stomach a churning motion, 

 rolling the food around and mixing it with the juices. The 

 stomach is guarded by a valve where the food enters which 

 prevents it from passing back through the gullet. There is 

 also a valve at the opening of the bowels, preventing any coarse, 

 undigested food from entering them. The stomach is held 

 in its place by five large ligaments, and is well supplied by blood 

 vessels and nerves. Digestion of food takes place very quickly in 

 the horse in comparison to other animals, and if, through a change 

 of food or working too soon after eating, the digestion is interfered 

 with it sets up what is known as indigestion, which is a very 



