GASTRIC ABSORPTION IN DIFFERENT .4NIMALS 1Q1 



fauces. Thirst is quenched by washing out the mouth with 

 water, or lubricating the dry throat with bland mucilaginous 

 fluids, sucking portions of ice, which horses with sore throats 

 soon learn to do, or swallowing slowly slightly acidulated 

 drinks, which, by stimulating secretion of saliva, moisten 

 the parched membrane. But thirst also depends upon a 

 deficiency of fluid in the body, and excess of soluble or 

 saline substances in the blood conditions which are 

 remedied by ingestion of water or other diluents. The 

 extreme thirst which occurs in horses affected with polyuria, 

 or diabetes insipidus, is best controlled by a combination 

 of iodine and opium. 



ACTION OP DRUGS ON THE STOMACH 



The stomach of the horse is small relatively to his size ; 

 the cardiac portion is lined with stratified epithelium, and 

 secretes no digestive fluid. The pyloric portion, which occu- 

 pies about one-half of the viscus, is the active digestive part, 

 and is lined with a vascular villous membrane, in which lie 

 the gastric glands. Gastric absorption in horses has been 

 questioned or denied since Bouley and Colin published their 

 experiments with strychnine ; but probably slow absorption 

 does take place from the right sac in a normal condition. In 

 ruminants, the first three compartments of the subdivided 

 stomach are lined with cuticular mucous membrane, are 

 chiefly occupied in the reception, maceration, and sub- 

 division of the bulky fibrous herbage, which constitutes their 

 principal diet. This thick epithelial covering, and the 

 amount of food always lodged in these three stomachs, ex- 

 plain the tardy action of many medicines administered to 

 ruminants, and their taking with impunity large doses of 

 irritants. The fourth stomach is lined with vascular velvet- 

 like mucous membrane, and secretes the gastric juice, while 

 from its walls slow absorption takes place. In the dog and 

 pig the stomach and digestive organs resemble those of man, 

 and in both animals absorption commences in the stomach. 



Secretion of gastric juice is stimulated by gentle mechani- 

 cal and chemical irritation, by introduction of suitable food 

 into the stomach, and by stimulation of the nerves of taste 



