36 SALIVA. 



mentioned glandular secretions and buccal or even nasal mucus. 

 (The nasal mucus alone did not possess this property). A mixture 

 of the secretions of the parotid and submaxillary glands, without 

 any secretion from the mucous membrane, was entirely deficient 

 in this property. 



To prove that the action of the saliva on starch is continued in 

 the stomach, the same author instituted the following experiments : 

 in one case he fed a dog in whom a gastric fistula had been esta- 

 blished, upon boiled starch after a twelve hours' fast; repeated expe- 

 riments showed that the contents of the stomach which were dis- 

 charged from the fistula contained sugar. In another case Jacu- 

 bowitsch introduced boiled starch through a fistulous opening into 

 the stomach of a dog, in whom the excretory ducts of the salivary 

 glands had been tied ; but here he could not discover any trace of 

 sugar in the contents of the stomach after a prolonged period. 



Wright attaches a very high degree of importance to the 

 alkalinity of the saliva both during insalivation and during gastric 

 digestion, and ascribes to it a second chemical function, viz., that of 

 saturating the excessive quantity of acid introduced into the 

 stomach or formed within it. It is certainly an undeniable fact 

 that alkaline saliva is secreted after the ingestioii of acid food ; but 

 this also occurs when highly seasoned food, spirituous liquors, and 

 other stimulants have been taken, which cannot have been saturated 

 or combined, like the acids, with the alkali of the saliva. It is 

 extremely doubtful whether the object of this secretion is to 

 saturate the free acid, since our experiments have in general rather 

 tended to show that an excess of acid in the stomach is less 

 injurious to the digestion of nitrogenous substances than any 

 deficiency in its quantity. For the present, therefore, we must 

 rest satisfied with admitting that as the saliva constantly becomes 

 alkaline during or after eating, even in those cases in which it was 

 acid before the ingestion of food, and as moreover its alkalinity 

 increases after taking indigestible or acrid substances, the alkali 

 probably contributes to promote the function of the saliva, although 

 we must leave it to future enquirers to determine the manner in 

 which this object is effected. 



Wright supports his assertion by an appeal to his own expe- 

 rience ; he found that the effect of spitting, after having partaken 

 of a full meal, was alway to induce an abundance of acidity with 

 much pain in the stomach, and a corresponding alkalinity in the 

 saliva. 



The saliva exerts no metamorphic action on any of the carbo- 



