iv DIGESTION IN THE INTESTINE 253 



concluded that digestion depends neither on the movements of the 

 stomach, nor on heat, but upon the gastric juices, which represent 

 the solvent for the food-stuffs introduced. 



Spallanzani, who had already demonstrated digestion in vitro 

 when Hunter's memoir was published, recognised in the post- 

 mortem digestion of the gastric walls a confirmation of his 

 discovery. Accordingly he set himself enthusiastically to repeat 

 and vary the experiments of Hunter, but since he did not know 

 the right conditions of external temperature and the most favour- 

 able pre-morteni period of digestion, he never succeeded in obtain- 

 ing rupture of the stomach, but only a dissolution of the mucous 

 membrane near the fundus. From this he concluded that " the 

 abdominal sheaths of dead animals are less subject to the influence 

 of the gastric juices than the meat introduced into the interior 

 of the stomach." After feeding a fasting dog on some fragments 

 of another dog's stomach, killing it at once by strangulation, 

 and keeping the body in a warm place for nine hours, after which 

 he made the post-mortem, he writes as follows : " The dissolution of 

 these pieces of stomach was very marked, while nothing, on the 

 contrary, was seen in the walls of the stomach in the dog that had 

 been killed, save a slight maceration of the large end of the 

 stomach, owing to which the villous coat when touched with the 

 finger or other body is readily detached and dissolved." He 

 explains this fact on the assumption that the fragments of 

 stomach, " being free and floating in the visceral cavity, were 

 covered at every surface by the gastric juice, while the walls of the 

 stomach were subject to its action on the inner surface alone." 

 Another conclusion is implicit in these words, viz. that the 

 epithelium that clothes the mucous membrane of the stomach is 

 even after death more resistant to the solvent action of the gastric 

 juice than the muscular and serous coats of the gastric walls. He 

 convinced himself by his experiments as a whole of the fact 

 Hunter had discovered, of the post-mortem auto-digestion of the 

 stomach, and accepted his explanation. He only protested that 

 the phenomenon could not be independent of heat, " too many 

 facts being cited in this book which point infallibly to the opposite 

 conclusion." 



In 1856 Pavy undertook to disprove the interpretation given 

 by Hunter of auto-digestion. Hunter, to support his position, had 

 propounded the following bold proposition : if it were possible to 

 introduce the hand into the stomach of a living animal, it would 

 resist digestion ; this would not occur if the hand were severed 

 from the body. Pavy showed this to be a fallacy, for he found 

 that the hind limb of a living frog, and the ear of a live rabbit, 

 introduced into the stomach of a dog by gastric fistula, did not 

 escape the action of the digestive juice. Hence he concluded that 

 " vital force " is incapable of protecting the tissues either of cold- 



