A STUDY OF WHEAT. 39 



the wheat, that is, near the tip of the cone. It is more readily 

 acted upon by a weak solution of potassic hydrate than wheat. 

 The solution should be 1.75 parts of potassic hydrate with 100. 

 parts of, distilled water. This expands potato starch while it 

 does not seem to affect wheat. The potato starch grains swell, 

 up to an enormous size, frequently fifteen times their original . 

 dimensions, while the rings . are entirely destroyed which gives t 

 them a flake-white appearance, A weak solution of iodine will 

 affect potato starch much quicker than it will wheat. Still both 

 the potassic hydrate and the iodine will affect the wheat starch, 

 although the statement has been made several times that such 

 is not the case. The truth of this can easily be proved by. 

 trial. Nitric acid has the property of coloring flour an orange 

 yellow while it does not change the color of potato starch. . 

 If the specimen of flour be adulterated with potato starch it 

 will not assume the same bright yellow color which pure flour 

 has on the application of nitric acid. 



The presence . of potato starch may generally be detected, 

 even with the unaided eye, by the minute glistening appear- 

 ance or the scintillations which are so characteristic of potato 

 starch. The structure of the potato itself is very simple, the 

 whole of the central part being made up of large hexagonal 

 cells with very thin walls, and they are packed full of starch. 

 A very good idea of their appearance is obtained from the il- 

 lustration of the hexagonal cells of wheat, Fig. 5, page 118 of 

 the April American Miller, 1880. So , in addition to the, starch 

 grains when examined under the microscope, we occasionally 

 see very delicate fragments of cellulose. Any person who in- 

 tends making a study of this subject should become perfectly 

 familiar with the appearance of potato starch under the mi- 

 croscope before he attempts to examine wheat flour for its adul- 

 terations. 



Indian Corn, or maize, is one of the most common adul- 

 terations of wheat flour. The name corn is frequently applied 

 to the fruit of all the cereals, and so it was used when men- 

 tion was made of corn in the Bible and in Roman history, 

 while Irtdian corn was known only after the discovery of 

 America. The botanical name is Zea Mais, and belongs to 

 the family of Graminece. It is a native of tropical America, 



