54 HORSE MANAGEMENT IN INDIA. 



100 *5 F. During exercise, there is a proportionate 

 increase in the amount of tissue broken up by these 

 chemical combinations taking place ; but the greater 

 portion of the excess of heat appears to be utilized by 

 its becoming converted into motion ; for we find that 

 after rapid movement, which is necessarily accom- 

 panied by considerable waste of tissue, there is but a 

 very slight increase in the temperature of the body. 

 This is in accordance with the fact that heat and 

 motion are but modifications, though under different 

 forms, of force. 



Mineral Substances. These, with the exception 

 of common salt, are obtained in ample sufficiency from 

 the various grasses. Corn contains them in a far 

 smaller proportion (see page 49) : hence the necessity 

 of the former food. We may observe, as before 

 remarked, that bran contains a large proportion of 

 phosphorus, which is an indispensable factor in all the 

 functions of life. 



The phosphates of lime and magnesia, the carbonate 

 of lime, and silica are the chief agents that give solidity 

 to the bony skeleton. The phosphate and carbonate of 

 soda " would seem to have as their chief purpose the 

 maintenance of the alkalinity of the blood, on which 

 depends not merely the solubility of its albumen, but the 

 facility of its passage through the capillaries, and the 

 readiness with which its combustive materials are 

 oxidized, whilst they also increase the absorptive power 

 of the serum for gases, and thus play an important 

 part in the respiratory process. The salts of potash 

 appear to be specially required for the nutrition of the 

 muscles and nerves, since they are largely present in 



