DIGESTION AND FOOD. 31 



was much less advanced. When the meat was entirely di- 

 gested in the warm fluid, it was very little changed in the 

 cold fluid. At the end of twenty-four hours the last was no 

 more digested. But then he warmed this fluid to 100, and 

 kept it at that temperature, and digestion commenced and 

 advanced regularly, as in the other parcels. 



51. In his other experiments, Dr. Beaumont found that 

 cold gastric juice acted not at all, or very imperfectly. 

 Hence he concluded that heat to a certain degree is neces- 

 sary, to give it the power of dissolving food. Dr. Carpenter 

 thence infers that the practice of eating ice after dinner, or 

 even drinking cold fluids or ice-water during dinner, or at 

 any time of eating, is very prejudicial to digestion. If this 

 be true, then all drinks which are colder than the stomach 

 must interfere with the action of the gastric juice to an ex- 

 tent in proportion to their coldness. For, if a temperature of 

 100 is necessary for digestion, then any thing, whether food 

 or drink, that cools the gastric juice below this degree, must 

 suspend the digestive process until the heat of the body, or 

 living power of the stomach, shall warm the fluid up to the 

 necessary temperature. 



52. The stomach (Fig. IV.) is large, and has its principal 

 cavity at the left end, where the food is received through the 

 oesophagus from the mouth. It grows smaller towards the 

 opposite end, and finally opens, by a small aperture at its right 

 extremity, into the intestinal canal. At this point of junc- 

 tion, it is surrounded by a strong circular band of muscular 

 fibres, which, by contraction, can completely close the open- 

 ing, as a string closes the mouth of a bag, and prevent the 

 passage of any thing through. This is the pyloric valve, 

 (Fig. IV. b,) which acts as a faithful sentinel, and retains 

 the contents of the stomach during the process of digestion. 

 While the food is undergoing the operation of churning and 

 mingling with the gastric juice, it binds itself closely around 

 the passage-way. The motions of the stomach, and the 

 pressure of the respiratory muscles, would very naturally 

 force the food out of this sack, if it were not thus effectually 

 secured. 



