284 



FOODS AND FEEDING. 



XIII. 



Availability : Measured by the difference between the total 

 food and the faeces. 



The former is almost impossible to determine, because of the 

 difficulty of distinguishing between the undigested residue of 

 the food and the matter which is derived from the digestive 

 fluids. 



AVERAGE DIGESTION COEFFICIENTS 

 IN VARIOUS FOODS. 



I. For Ruminants. 



* According to experiments with sheep by Fraps (Journal of Amer. Chem. Sue. 

 1900,543; Jour. Soc. Chem. Ind. 1900, 1030), sugars are completely digestible, while 

 pentosans, on the average, have a digestion coefficient of 64'3. The order of digesti- 

 bility of non-nitrogenous food constituents is (1) sugar, (2) starch, (3) pentosans, 

 (4) residue (" crude fibre"). 



