33 



First we notice the effect of an excess of food. In this we must 

 consider the horse as a machine, which has a certain limited capa- 

 city for converting so much raw material into a finished product. 

 We supply the horse with hay and grain, and expect in return for 

 our outlay a definite amount of energy. Within certain limits the 

 quantity of the product does not depend so much upon what we 

 supply as upon the capacity of the organism to convert what is 

 given from one form into another. A horse can take in, digest, 

 assimilate and appropriate only a limited amount of material. If 

 more than this definite quantity be taken, the organism must of 

 necessity become taxed beyond its powers; e. g., if more food is 

 eaten than can be digested and absorbed, it accumulates in the 

 intestines, acting as foreign material, produces irritation, causing 

 colic or a similar disorder. If, on the other hand, more food is 

 taken, digested and absorbed than can be appropriated by the dif- 

 ferent tissues, a condition of plethora results, in which the circula- 

 tory system or the lymphatic system becomes overloaded with 

 nitrogenous or other constituents. If overloading of the lymphatic 

 system of the extremities occurs, we have lymphangitis, or " Mon- 

 day morning disease," produced. 



By many people a mistake is made in that they believe it 

 possible, by allowing excessive quantities of rich food, to keep an 

 overworked animal in good condition. If we investigate this sub- 

 ject we shall see that such is not the case. Work brings about 

 rapid destruction of the tissue. The material to repair or replace 

 the destroyed tissue is contained in the food of the animal. It 

 must be brought into a suitable condition by digestion before it 

 can be appropriated by the tissue cells. The digestive organs are 

 capable of a definite amount of work, and an excessive destruction 

 of tissue over what can be replaced through digested food must 

 remain, for a time at least, unrepaired. The undigested residue 

 of the, excessive quantity of food must remain in the intestinal 

 tract, and it may become the cause of disease. In case of over- 

 worked animals, the richer, moi'e concentrated and easily digested 

 the food, the greater the amount appropriated by the tissues. At 

 the same time, it should be remembered that the retention in the 

 intestines of undigested material rich in nitrogenous constituents 

 is attended with more danger than in case of retention of less rich 

 food. An over-feed of grain may cause serious consequences, 

 whereas an over-feed of hay rarely does harm. The influence of 

 breed and individual peculiarities are so marked in relation to di- 

 gestion that it is impossible to establish a rule that will apply in 

 all cases. Our aim should always be to supply food in sufficient 

 quantities, in an easily digestible form, so that enough nutrient 



