ABSORPTION IN THE INTESTINES 



absorbed by the stomach only to a slight extent in the weaker solutions, 

 but are readily absorbed when the more concented solutions are introduced 

 into the stomach, five per cent and over (von Mehring). Fats are not absorbed 

 at all in the stomach. Even salts in the stomach are not readily absorbed 

 until this concentration is from three to four times that of the blood. This 

 fact is in direct opposition to the popular views on the subject. 



While some absorption does take place in the stomach it is evidently not 

 of any great importance under normal conditions. The presence of alcohol 

 has been shown to increase the amount of absorption, and pepper, mustard, 

 and such drugs as produce mild local irritation accomplish the same result. 



Absorption in the Intestines. The products of digestion are all 

 absorbed in the small intestine, as is abundantly shown by experiments. 



' 



FIG. 279. Scheme of Blood-vessels and Lymphatics of Human Small Intestine, a, Central 

 lacteal of villus; b, lacteal; c, stroma; d, muscularis mucosae; e, submucosa; /, plexus of lymph- 

 vessels; g, circular muscle layer; h, plexus of lymph- vessels; *', longitudinal muscle layer; /, serous 

 coat; k, vein; /.artery; m, base of villus; n, crypt; { o, artery of villus; p, vein of villus; g, epithe- 

 lium. (Mall.) 



Absorption from the small intestine has been studied in the human subject 

 in the case of a patient who had a fistulous opening in the lower part of the 

 ileum. For example, 85 per cent of the proteid of a test meal was absorbed 

 before the food reached the fistuh. The food passes slowly down the length 



