FOOD 91 



ordinary hay is employed. There is little difference in the proportions 

 of albuminoids assimilated by the two animals, but the divergence becomes 

 considerable when we come to the carbohydrates, fibre, and fat. Of the 

 carbohydrates the horse digests 7 to 10 per cent, of the fibre 21 per cent, 

 and of the fat and waxy matter 25 to 52 per cent less than the sheep. 

 On the whole, the horse digests about 12 per cent less of the total organic 

 matter of grass hay than the sheep. With red clover hay the results with 

 the horse are better. With Lucerne hay of good quality the digestion of 

 the horse is still better, and (save as regards the fat) practically equals 

 that of the sheep. 



The smaller digestive power of the horse for vegetable fibre is plainly 

 connected with the fact that it is not, like the sheep, a ruminant animal, 

 and it is thus unprovided with the same means of attacking an insoluble 

 food. In a trial with wheat- straw chaff, the horse digested 22 '5 and the 

 sheep 47' 6 per cent of the total organic matter. 



With the corn the digestion of the horse is apparently quite equal to 

 that of the sheep. No stress must, of course, be laid on the digestion co- 

 efficients found for ingredients of the food present in small quantity, as the 

 fat and fibre of beans and the fibre of maize. In French experiments on 

 horses, in which maize or beans were consumed alone without the addition of 

 hay, it was found that with maize 94 '5 per cent of the total organic matter 

 and 87 '1 per cent of the nitrogenous substance, and with beans 90 '4 per cent 

 and 89 '3 per cent respectively were digested. Of potatoes 93 per cent, and 

 of carrots 87 per cent of the organic matter were digested by the horse. 



A difficulty which attends all experiments of this kind, in which special 

 kinds of foods are given exclusively, is that their digestibility will be neces- 

 sarily affected more or less when they are mixed with other foods. This is 

 proved by the following facts, recorded by the same authority. 



If to a diet of hay and straw, consumed by a ruminant animal, a pure 

 albuminoid, as wheat gluten, be added, the added food is entirely digested 

 without the rate of digestion of the ordinary food being sensibly altered. 

 The same result has been obtained in experiments with pigs fed on potatoes 

 to which variable quantities of meal-flour were afterwards added. The 

 albuminoids of the meal were entirely digested, while the proportion of the 

 potatoes digested remained unchanged. 



An addition of oil (olive, poppy, and rape oil) to a diet of hay and 

 straw is also apparently without unfavourable influence on the rate of 

 digestion; indeed, some experiments with small quantities of oil (|- Ib. of oil 

 per day per 1000 Ibs. live weight) show an improved digestion of the dry 

 fodder; oil supplied in moderate quantities is itself entirely digested. 



An addition of starch or sugar to a diet of hay or straw will, on the 



