THE MINERAL SALTS 13 



ash, some are of vital importance in the economy of both plants 

 and animals. Others, though normally present, are probably 

 not indispensable, but may be of use indirectly. From the 

 point of view of the practical cattle feeder they are all 

 unimportant inasmuch as they are always present in the 

 natural food of the animals. If the food be sufficient in 

 quantity and suitable in other respects, it will certainly contain 

 enough " mineral salts " for all ordinary purposes. It is 

 unnecessary, therefore, to add any ash ingredients, except 

 common salt, to the ordinary rations of the animals. 



