€08 CERTAIN GASTRIC SYMPTOMS AND FUNCTIONAL DISORDERS. 



CHAPTER XXXVI. 



OF CERTAIN GASTRIC SYMPTOMS AND FUNCTIONAL DISORDERS. 



I. Vomiting — Emesis. 



Definition. — The act of forcibly ejecting the contents of the 

 stomach through the oesophagus in response to direct disturbance 

 of the brain, or from reflex irritation. 



This condition, common enough in all other animals which 

 engage our attention, is of rather rare occurrence in the 

 horse. Why this phenomenon should so seldom exhibit itself 

 in him has from an early period engaged the attention of 

 physiologists and experimenters. 



The two chief considerations which have been advanced to 

 account for the rarity of this occurrence in the horse are — 

 (1) The physiological one of the small susceptibility which the 

 animal exhibits to the action of nauseants; and (2) The 

 alleged physical difficulty depending on the anatomical con- 

 formation of the viscus, particularly its possession of a con- 

 stricting or valvular arrangement at the cardiac opening, by 

 which the contents are prevented from escaping into the 

 oesophagus. 



Without entering into the question of the strength or weak- 

 ness of the arguments and collections of facts brought forward 

 to prove either of these statements, we may state that — insus- 

 ceptible as the horse is to the action of emetics, and rare as 

 nausea, the primary inducing factor in the production of 

 €mesis, seems to be — vomition, or the forcible ejectment 

 of the contents of the stomach through the oesophagus, is 

 met with under varying conditions. The states in which it 

 seems highly probable that such may occur, are not those 

 following the induction of nausea in any marked degree, or 

 when there is direct action upon the nervous system, but arc 

 all of them such as pertain to some peculiar state of the organ 

 itself; all seem to have a definite relation to its anatomical 

 characters, particularly to the state of the lining membrane. 



I have observed it — 



1. When the stomach has been much distended with 

 ingesta, chiefly of a solid nature, and prone to fermentative 



