vmj in the Eighteenth Century. 215 



in the case of tubes which had passed into the fourth stomach. 

 But, remembering that the sheep always ruminated, and pre- 

 pared its food for solution by prolonged mastication, he repeated 

 the experiment with the variation that he carefully masticated 

 the food, herbs or hay, before he introduced it into the tubes. 

 He then found that the contents of the tubes were largely 

 dissolved. He concluded that mastication, with the attendant 

 admixture of saliva was like the trituration in the muscular 

 stomachs, a preparation for the solvent action of the gastric juice. 



His experiments with gastric juice removed from the living 

 stomach and made to act on food in vitro fully confirmed the 

 results obtained in the living stomach itself. Food of very 

 various kinds thus exposed to the action of gastric juice was 

 dissolved and did not putrefy, whereas the same food subjected 

 to the action of simple water soon putrefied. Solution in vitro 

 was however never so rapid or complete as in the living 

 stomach. Thinking that this might be due to the fact that in 

 the experiment out of the body the gastric juice is not renewed 

 as it is in the living stomach, he endeavoured to imitate the 

 natural process by allowing his gastric juice to fall drop by 

 drop on, and to run away drop by drop from, pieces of meat and 

 bread. He now found that " solution took place with exceeding 

 "speed." He observed that in all cases heat favoured solution ; 

 indeed in warm-blooded animals a certain high temperature 

 seemed to him necessary, though cold-blooded animals did not 

 need this. 



It was clear from his experiments that gastric juice was a 

 powerful solvent of all kinds of food. The question now arose, 

 What was the nature of this solvent power? "It remains," 

 says he, "to be inquired whether this function is connected 

 " with a principle of acidity, as some suppose, or of putrefaction 

 " according to others." 



The supposition of putrefaction was soon disposed of; so 

 far from producing or even assisting putrefaction, the gastric 

 juice was actually opposed to putrefaction; meat which in 

 simple water readily putrefied in the warm, remained sweet in 

 gastric juice kept equally warm ; the gastric juice even de- 

 stroyed the putridity of putrid meat. 



