48 THE PLANT. 



hardly apparent, but as it grows older, as the grain 

 becomes heavier, (verging towards ripeness,) the 

 silicious coating of tlie stalk assumes a more prom- 

 inent character, and gives to the straw sufficient 

 strengtli to support the golden head. The straw is 

 not tiie most important part of the plant us, food, anc- 

 it contains but little phosphoric acid, which is so 

 necessary to animals. 



The grain, on the contrarj^, is especially intended 

 as food, and therefore must contain a large propor- 

 tion of phosphoric acid — this being, as we have al- 

 I'eady learned, necessary to the formation of bone — 

 while, as it has little necessity for strength, and as 

 silicic acid is not needed by animals, this ingredient 

 (ixists in the grain only in a very small proportion. 

 It may be well to observe that the ])hosphoric acid 

 of grain exists most largely in the hard portions near 

 the shell, or bran. This is one of the reasons why 

 Graham (or unbolted)ifluur is more wholesome than 

 fine flour. It contains all of the nutritive raat-erials 

 Avhicli render the grain valuable as food, while flour 

 which is very finely bolted* contains only a small 

 part of the outer portions of the grain (where the 

 phosphoric acid, protein and fatty matters exist most 

 largely). The starchy matter in the interior of the 

 grain, which is the least capable of giving strength 

 to the animal, is carefully separated, and used as food 

 for man, while the better portions, not being ground 

 so finely, are rejected. This one thing alone may be 

 sufficient to account for the fiict, that the lives of 

 * Sifted through a fine cloth called a bolting cloth. 



