28 GENERAL THERAPEUTICS FOR VETERINARIANS 



tance is the antiseptic and antizymotic action of the hydrochloric 

 acid. In consequence of the presence of this substance the gastric 

 juice is a natural protective agent against abnonnal fermentative 

 and putrefactive processes, and likewise against pathogenic bac- 

 teria. These facts are of the greatest therapeutic importance 

 (prophylactic, causal, radical treatment of disease). It is also 

 worthy of note that the antiseptic protective action of hydrochloric 

 acid may be obtained from other acids, as lactic, acetic and phos- 

 phoric. The proteolytic or peptonizing action of the gastric juice, 

 or of the pepsin, is only of secondary consideration therapeutically. 

 Moreover, the digestion of proteids is not an exclusive physiological 

 function of the stomach, but can be entirely accomplished by the 

 pancreatic ferment (trypsin) and in part by the enzyme of the intes- 

 tinal juice (erepsin). The proteoljd;ic action of pepsin in the 

 stomach occurs only when the contents are acid (hydrochloric, 

 lactic, acetic acid). The optimum acidity is 0.2 per cent. If the 

 acidity is less than 0.1 per cent, or more than 0.6 per cent, peptoni- 

 zation is inhibited. Accordingly, the average therapeutic dose of 

 hydrochloric acid for the horse is 15 grams [one-half ounce], figuring 

 the volume of the stomach to be 15 litres [15 quarts]. Absorption 

 is relatively slight in the full stomach, especially in the stomach of 

 the horse and in the first three stomachs of ruminants, and is 

 limited to fluids or dissolved food and medicines. It is more rapid 

 in the empty stomach of the fasting animal, especially in the 

 stomach of dogs and in the abomasum of ruminants. These facts 

 should be considered in administering medicines. On the other 

 hand, of no special therapeutic importance are the different periods 

 of gastric digestion in the horse (proteolytic pepsin digestion, amyl- 

 olytic action of the saliva, mixed digestion) or the fact that in 

 ruminants only maceration (rumen) and amylolytic (saliva) diges- 

 tion occurs in the first three stomachs and proteolytic digestion in 

 the fourth. More important is the fact that the contents of the 

 stomach are arranged in layers and that no mixing takes place. 



Therapeutic Methods. — Diseases of the stomach may be 

 treated in several different ways. The methods most used are the 

 dietetic, the medical, the mechanical, and the operative. 



