30 CEREALS 



other cereals. It is a native of northern Asia where doubt- 

 less it has been cultivated for a long time; yet its introduc- 

 tion into other regions was comparatively recent. Like rye 

 its chief merit is that it will yield a jDrofitable crop on very 

 poor soil. The flour made from it, however, is correspond- 

 ingly poor in nutritive value. It is usually mixed with other 

 sorts of flour to which it imparts an agreeable flavor. 



25. The value of cereals. Why is it that the cereal grains 

 have been valued so highly from the earliest times? What 

 makes them so much better than other vegetable foods, 

 and why are some of them sujjerior to others? The fact 

 that these plants ripen their seeds within a few months after 

 planting, and under favoraljle conditions j'ield such a large 

 return for the labor bestowed upon them, will doubtless 

 partly account for the high favor in which they are held; 

 but as much the same may be said of other vegetables of far 

 less value as food, thei-e must be some more important 

 reasons. In order to understand these, we must know some- 

 thing of tlie chemical composition of cereals; that is to say, 

 we must learn what substances are to lie found in the differ- 

 ent grains and in what amount. 



26. Water in grains. Every part of a plant contains or- 

 dinarily a certain quantity of tvater — succulent herbage and 

 fruits like the watermelon having a great deal, while woody 

 parts, seeds, and grains have comparatively little. The 

 quantity of water contained in a given specimen, is esti- 

 mated by drying a known weight of the material at the tem- 

 perature of boiling water, and then reweighing to find how 

 much has been lost: the loss will be practically equivalent to 

 the weight of water originally present. In the Food Chart on 

 page 114 the student will find indicated the average percent- 

 age of moisture in each of the cereals and in various other 

 vegetable foods as commonly found in the markets. A 

 glance will show what a comparatively small amount the 

 cereals contain. For this reason they keep remarkably well 

 when stored, and take up very little room in proportion 

 to the amount of nutriment they afford. 



27. Ash. If the sample dried as suggested be burned 

 until all of the combustible material is consumed, there will 



