( 



Ash in Plants 43 



water or other solvents would have upon the inorganic 

 portion of cattle foods. 



The mineral compounds of ])lants. — All plants and 

 feeding stuffs contain mineral compounds, which are 

 important in this connection because, excepting com- 

 mon salt, they are the only source of the mineral con- 

 stituents of the animal body. These are held in the 

 plant tissue chiefly in three ways; in solution in the 

 juices, in crystals in the cells and as incrustations in 

 the cell walls. With the exception of oxj'gen, sulfur 

 and phosphorus, no ingredient of the ash has sus- 

 tained, so far as known, a structural relation to plant 

 growth. When the fresh plant substance is reduced to 

 an air -dry condition, the salts in solution become de- 

 posited in the tissues as solids. The mineral matter 

 of plants and feeding stuffs is by no means uniform 

 in composition and quantity, even in the same species 

 or class of materials, although in some grains there is 

 a fair degree of similarity in this respect. Certain 

 factors cause variations, such as species, stage of 

 growth, fertility, the part of the plant, manner of 

 curing or treatment of a feeding stuff and changes due 

 to manufacturing processes, and the variations which 

 exist pertain 'not only to the amount of ash but also 

 to its composition. 



Variations due to species. — Different species of 

 plants, and consequently different feeding stuffs, are 

 greatly unlike in their content of mineral matter. The 

 figures below illustrate this fact, further confirmation 

 of which may be had by consulting the table in the 

 appendix: 



