FOODS ANIMAL PRODUCTION. 473 



ash content of rye flour is a criterion of its value. Bread always bad a 

 higber asb content than the flour from which it was made. The protein, 

 ash, and fat content of the feces from the different sorts of bread varied 

 witbin narrow limits. Persons wbo are accustomed habitually to con- 

 sume large amounts of carbohydrates, especially bread, digest bread 

 better than those who are accustomed to eat large quantities of meat. 

 Well-baked bread from the finest rye flour was as well assimilated as 

 wheat bread. 



The chemical composition of the feces on different diets, W. 

 Prausnitz (Ztschr. Biol., 35, No. 3, pp. 335-354). — A number of experi- 

 ments are reported in which the comx)osition of the feces was deter- 

 mined. 



Among the conclusions reached were the following: When the diet 

 consists of foods which are almost completely absorbed, as rice, meat, 

 bread, etc., the composition of the feces is independent of that of the 

 food and is practically uniform. When the food is less completely 

 absorbed the nitrogen content of the feces usually diminishes. Under 

 ordinary circumstances the chemical composition of the feces is never 

 the same as that of the food but generally has a high nitrogen content. 

 There is no especial difference in the assimilation of animal and vege- 

 table nutrients in the human intestinal tract. The assimilation is 

 dependent solely upon the method of preparation. In these experi- 

 ments rice and foods made from tine flour were most thoroughly assim- 

 ilated, only traces being found in the feces. Somewhat larger quan- 

 tities of undigested residue of meat were found even under the most 

 favorable circumstances. With few exceptions human feces are chiefly 

 made up of intestinal secretions, and not of undigested residue. 



The vegetable matter in human feces, J. Moeller (Ztschr. Biol, 

 35, No. 3, pp. 291-315). — The author studied with a microscope the com- 

 position of feces on a vegetable diet. Small portions were diluted with 

 considerable water, filtered, and repeatedly washed until a colorless 

 filtrate was obtained. The portion remaining on the filter was examined. 



Among the conclusions reached were the following: In the case of 

 healthy individuals the starch of cereals and potatoes is almost com- 

 pletely digested, even if the starchy food materials are not in the most 

 favorable mechanical condition, as in the case of rice or slices of potato. 

 Some starch escapes digestion when consumed in such foods as legumes 

 or green vegetables. The thick cells of ripe legumes, although com- 

 posed of almost pure cellulose, were apparently not at all digested. 

 On the other hand, the starch of unripe legumes appeared to be almost 

 as completely digested as that of the cereals. The seed coat of leg- 

 umes and the gluten layer of cereals are not at all digested, although 

 composed of almost pure cellulose. The same is true of the protein and 

 fat inside the cells in the gluten layer of cereals unless the cell walls are 

 broken. The amount of gluten in cereals materially affects their diges- 

 tion. The characteristic cells and tissues of vegetables are found in 



