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Page:Popular Science Monthly Volume 56.djvu/733

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something worse than we should care to even dream of. When there is a shortage of starch in India, a distress follows that is felt through the bonds of sympathy, if in no other way, the whole world round. Let rice fail to mature its grain, PSM V56 D0733 Starch granules of corn.pngFig. 2.—Starch Granules of Corn. which means, in short, not to store its starch in available form for man, and the dependent race is brought to the ghostly condition of starvation and thrown upon the charity of those people whose starch is in their grain elevators, sacks, and barrels almost without number.

Starch, it would seem from this, is the prime food element of the human family, the chief factor in the upbuilding of a race, because a fundamental aliment of our bodies.

If the starch' factories do not make, in the true sense, the product of their mills, it may be to the point to consider how this all-important substance comes into existence. The organic chemist tells us that starch is a ternary compound, and this agrees closely with the definition laid down by the dictionaries, only they add that it is odorless, tasteless, and insoluble in water. It is one of the proximate principles of plants, and is stored in the form of granules wonderfully variable in size and shape, but each kind having a type that is adhered to with much regularity. For example, the ordinary potato (Solanum tuberosum L.) produces a starch granule that is characterized by a form resembling the shell of the oyster. Fig. 1 is from a camera drawing of a cell from the center of a potato, with portions of adjoining cells, all of which were packed full of starch, a few grains only being represented.

Starch is acted upon differently by reagents, one of the leading tests for it being a solution of iodine. A drop of a very weak solution will determine the presence of starch in a cuff or shirt front by leaving a blue spot or streak where the iodine has been applied. By means of this reagent the student of plant tissues is readily able to locate starch when present in any slice of tissue he may have made. He would, for example, find much more starch in the tuber of the potato than in any other portion of the plant, and there the grains will be found many times larger than in the stem or the cells of the green leaves. Of the relation of the starch in