48 T1IE PLANT. 



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

 becomes heavier, (verging towards ripeness,) the 

 silicious coating of the stalk assumes a more prom- 

 inent character, and gives to the straw sufficient 

 strength to support the golden head. The straw is 

 not the most important part of the plant a,sfood, and 

 it contains but little phosphoric acid, which is so 

 necessary to animals. 



The grain, on the contrary, is especially intended 

 as food, and therefore must contain a large propor- 

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

 ready 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 

 exists in the grain only in a very small proportion. 

 It may be well to observe that the phosphoric 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) flour is more wholesome than 

 fine flour. It contains all of the nutritive materials 

 which 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 fact, that the lives of 

 * Sifted through a fine cloth called a bolting cloth. 



