COMPAKATIVE DIGESTIBILITY OF FOOD-STUFFS. 437 



As a rule, it may be stated that the ox is capable of digesting the 

 following amounts: 



Albuminoids. Cellulose. 



Oats, . 49 per cent. 55 per cent. 44 per cent. 



Wheat-straw, 26 52 39 



Bean-straw, 51 " 36 " 62 



Clover-straw, 51 ' 39 67 



Barley-hay, 60 " 60 '* 67 " 



Henneberg has found that the digestibility of a fodder is altered 

 when a second nutritive substance is added to it. Thus, the digestibility 

 of any fodder is reduced by the addition of starch, while, on the other 

 hand, the addition of fat facilitates the digestion of albuminoids and 

 cellulose. In general, it may be stated that the digestibility of any dry 

 fodder is decreased by the addition of any readily digestible substance, 

 such as albumen, starch, sugar, and in ordinary fattening diet a loss of 

 at least 20 per cent, of nutritive substances may be calculated. This 

 author's experiments have further shown that at least five days are 

 required after the change of diet before the traces of indigestible food 

 are removed from the faeces, and that the removal of the residue of 

 prairie haj^ occurred about thirty hours before that of wheat-straw. In 

 the calf, experiments have been made to determine the digestibility of 

 cereals and grains taken whole, with the following results: 



Oats. Flaxseed. Barley. Wheat. 



Digested, . .' . 91.4 58.2 94.6 36.3 



. . . 91.5 57.4 94.9 36.7 



In the sheep the same results have been obtained as in the ox. An 

 addition of starch or sugar to the food diminishes considerably the 

 digestibility of the albumen and, when in small amount, of the cellulose 

 also. Pure albumen has slight influence on the digestibility of the food. 

 Substances containing sugar, with the exception of beets, are almost 

 entirely digested, while in potato-starch 80 per cent, is digestible, and fat, 

 when added to fodder, is usually absorbed, though its administration 

 when given in large amounts interferes with the digestion of cellulose. 



According to Wildt, lambs which were fed with barley-straw, and 

 then the residue from meat extracts, absorbed 95 per cent, of the latter. 

 Experiments on the horse have also proved that this animal is capable of 

 digesting cellulose to about 50 per cent. In comparison with the 

 ruminants, the horse is less capable of digesting all the constituents of 

 hay. The loss in the horse, as in other herbivora, is much greater than 

 in the carnivora. The carnivora may be said, as a rule, to absorb about 

 98 per cent, of albuminous matter given in the food. In a man fed on 

 milk and meat diet only 2J to 10 per cent, escapes in the faeces ; with 

 vegetable diet, rice, bread, and potatoes, the loss may amount to 30 per 



