112 



A Manual of Veterinary Physiology. 



digestion when it contains about 17^ pints, or is distended 

 to two-thirds of its capacity. 



The mucous membrane of the stomach of the horse is 

 peculiar; one portion of it, practically half, is a continuation 

 of the membrane of the oesophagus ; this .ends abruptly, 

 and then the villous coat commences which runs to the 

 pylorus. It is in this coat that a true digestive juice is 

 secreted though not from the entire surface, for on examining 

 the villous membrane it is found to differ greatly in appear- 

 ance, the fundus being channelled or furrowed and velvety, 

 whilst the pyloric portion is smooth. It is in the fundus 

 only where true gastric juice, viz., pepsin and acid, is 



Fig, 8.— Longitddinal Section of the Stoma< h of the Horse, 



showing the Syphon Trap or the Duodenum. 

 u .. oesophagus ; py., pyloius ; d, left sac ; r, fundus ; duo., duodenum. 



secreted, in the smooth pyloric mucous membrane only 

 pepsin is formed, but this will be fully dealt with presently. 

 The area of the membrane of the fundus-secreting surface 

 is about one foot square. Fig. 7 shows the relative posi- 

 tion of the various parts of the mucous membrane of the 

 stomach of the horse. The drawing accurately indicates 

 the shape of the stomach, the position of the inlet and 

 outlet, and the direction and position of the various areas. 

 A very remarkable amount of mucin is secreted by the 



