THE PLANT. 53 



The stems, roots, branches, etc., of most plants 

 consist principally of woodi] jihre. 



Their seeds, and sometimes their roots, contain 

 considerable quantities oi stai^ch. 



The nitrogenized siihstances and the oils of most 

 plants exist most largely in the seeds, therefore seeds 

 are the most nutritious food for animals, because 

 they contain the largest proportion of digestible 

 matter. 



The location of the different compounds in tlie 

 plant, as well as of its mineral parts, shows a remark- 

 able reference to the purposes of growth, and to the 

 wants of the animal world, as is noticed in the 

 difference oetween the construction of the straw and 

 that of the kernel of wheat. 



The reason why the fine flour now made is not 

 so healthfully nutritious as that which contained 

 more of the coarse portions, is that it is robbed of a 

 large proportion of protein and phosphate of lime, 

 while it contains an undue amount of starch, which 

 is available only to form fat, and to supply fuel to 

 the lungs. 



Different plants have ashes of different composi- 

 tion. Thus — one may take 'from the soil large 

 quantities of potash, another of phosphoric acid, and 

 another of lime. By understanding these differ- 

 ences, we shall be able so to regulate our rotations 

 that the soil may not be called on to supply more of 

 one ingredient than of another, and thus it may be 

 kept in balance. 



The facts contained in this chapter are the alpha' 



