782 PHYSIOLOGY OF DIGESTION AND SECRETION. 



concentrated (5 per cent.), and we may infer, therefore, that in att 

 ordinary meal the sugar formed from the starchy foods by the 

 action of the ptyahn is passed on to the intestine for further diges- 

 tion and absorption. Whether or not any of the digested proteins 

 are absorbed from the stomach has been and still is a matter of 

 controversy. Some of the older experimenters stated that as 

 much as 20 to 30 per cent, of the protein of a meal might be 

 absorbed in the stomach, but the results of the more recent work, 

 on the contrary, indicate that little or no absorption takes place 

 under normal conditions.* When a definite amount of protein was 

 introduced into the stomach of an experimental animal it could 

 all be recovered, as estimated by nitrogen determinations, from a 

 duodenal fistula. 



Fats. — As we have seen, fats probably undergo no digestive 

 changes in the stomach. The processes of saponification and emul- 

 sification are supposed to be preliminary steps to absorption, and 

 these processes take place usually after the fats have reached the 

 small intestine. 



* London, loc. cit. 



