FAT IN THE INTESTINAL WALL 353 



and of cholesterine from the bile, physical-chemical condi- 

 tions in the contents of the small intestine are determined in 

 which the cleavage products of the fat are kept in solution 

 no matter whether an acid or an alkaline reaction may 

 prevail. This is true not only of the free fatty acids, but 

 also of their relatively insoluble calcium and magnesium 

 salts. 



Synthesis of Fat in the Intestinal Wall. The possibility 

 of fat synthesis in the wall of the bowel is very clearly indi- 

 cated from the experiments of J. Munk, and those of 0. 

 Frank ; it has been shown that in the chyle of the thoracic 

 duct neutral fat is present, not only after the administration 

 of neutral fat, but also when the fatty acids, their alkaline 

 salts and esters are ingested. Where the glycerol comes from 

 which is necessary in such a synthetic formation is not 

 known; it must suffice for the present to know that it can 

 be produced apparently in unlimited amount by the intes- 

 tinal wall. If this were not true it would be impossible to 

 understand how, after the ingestion of large quantities of 

 soaps or free fatty acids, we invariably find only the tri- 

 glycerides in the lymph of the thoracic duct. The discovery 

 that soaps are poisonous when introduced directly into the 

 circulation and that for this reason it would be injudicious 

 to have them enter the circulation unchanged, is, of course, 

 no explanation. "We are here brought face to face with 

 another unsolved puzzle. If, however, the wall of the bowel 

 manages to carry out the synthetic formation of fat from 

 fatty acids and glycerol even when no glycerol is provided 

 for it, why should there be any doubt of its ability to com- 

 plete the synthesis if coincidently with the fatty acids 

 equivalent amounts of glycerol are resorbed from the lumen 

 of the bowel? 



From recent experiments of 0. Frank u it appears that 

 ingested monoglycerides do not enter the chyle as such but 



"A. Argyria and O. Frank (Munich), Zeitsch. f. Biol., 59, 143, 1912. 

 23 



