49 



torih^ opposed Liebig's idea of the high value of the gluten layer of 

 wheat. 



Perhaps the most extended study of vegetable residues occurring 

 in feces was made by Moeller". In some of the experiments the 

 diet consisted of coarse bread with butter and cheese; white bread, 

 rice, and butter; bread, and porridge made of wheat grits and milk; 

 bread, and porridge made from milk and flour; oat preparations, 

 namel}^ oat grits, oat flake, soup, and oat cocoa; rye bread and various 

 mixed diets, or diets in which potatoes or legumes predominated. 

 Portions of feces were repeatedh' washed with water and then exam- 

 ined under the microscope. The conclusion was reached that healthy 

 individuals digested the starch of cereals and potatoes almost completely, 

 even when the starchy foods were not in favorable mechanical condition, 

 as is the case in bran from cereals, in rice, or in sliced potatoes; and fur- 

 ther, that the soft cell walls of the starch cells are also digested. The 

 aleurone layer of cereals in which the cell membranes consist of pure 

 cellulose was not digested, nor were the protein and fat which form 

 the contents of the cells digested unless the cell walls had been mechan- 

 ically ruptured. The cells making up the germ were not digested or 

 ruptured by the action of the digestive juices. The author believes 

 that these experiments warrant the conclusion that line flour is prefer- 

 able to coarse flour. Comparative experiments with coarse flour and 

 the same flour after passing through the intestinal tract, lead the 

 author to the conclusion that the cell walls almost absolutely shield 

 the cell contents of the aleurone layer from the action of the digestive 

 juices, and he concludes that cereal brans should be regarded as indi- 

 gestible. The outer layer of the cereal grains, including endosperm 

 cells with their starch content, was also found to be undigested. 



Laborator}' experiments indicated that cellulose which had not ligni- 

 tied was little attacked by digestive juices, the amount being inversely 

 proportional to the thickness of the cell membrane. On the other 

 hand, the middle lamella were readily disintegrated by digestive juices. 

 Tests with laboratorv reagents also showed that the inner side of the 

 gluten cells was most resistant but after a time softened, and this indi- 

 cates that possibly gluten cells may become softened in the intestine 

 and then digested. That this occurs very seldom is indicated by the 

 large number of unchanged cells found in the feces. 



As noted above, in connection with the experiments reported in 

 this bulletin, a microscopical examination of the feces showed that 

 in those from the gi'aham and entire-wheat breads made from flour 

 ground from the same lot of soft wheat, a much larger number of 

 unaltered starch granules were present, and the particles had not been 

 as completely acted upon by the digestive fluids as in the case of the 

 straight-grade-flour bread. 



«Ztschr. Biol., 35 (1897), p. 291. 

 19047— No. 126—03 4 



