36 



PHYSIOLOGY OF FARM ANIMALS 



[CH. 



part of the small intestine. As already mentioned the horse's 

 stomach is relatively small, its average capacity being from 

 35 to 40 pints. It lies some distance from the body wall, being 

 supported by the colon Avhich is a part of the large intestine. 

 Its cardiac and pyloric openings are situated close together, and 

 the former is tightly contracted so as to make vomiting an act of 

 great difficulty. 



Pure gastric juice has not been obtaine^l from the horse's 

 stomach since owing to the distance between this organ and the 

 body wall it has been found impracticable to establish an artificial 

 connection between the secretory stomach and the outside of the 

 body as Pawlow and others have done in the case of the dog. 



Oesophagus 



■Body Wall 



Fig. 23. Pawlow's tistula. The a markings, indicate the line of sutures. 

 >J=closed fundie sac. The broken Une indicates the original outline 

 of the stomach prior to operation. 



Such a connection is called a gastric fistula, and the method of 

 establishing it has been to make a cul-de-sac of the cardiac end 

 of the stomach by reflecting the mucous membrane so as to form 

 a diaphragm between the two cavities (that is the cavity of the 

 cul-de-sac and the main cavity of the stomach), and to connect 

 the cul-de-sac with the abdominal wall so that it communicates 

 freely with the outside of the body in the manner shown in the 

 diagram. The vascular and nerve supply to the cul-de-sac 

 portion are allowed to remain intact. Pawlow also made an 

 oesophageal fistula in the dog, so that the food which was 



