_Indian Corn Starch._—The granules of maize starch are largely of the same size, from 0.02 to 0.03 millimeter in diameter, with now and then a few which are much smaller. They are mostly circular in shape or rather polyhedral, with rounded angles, as shown in Figs. 58 and 61. They form very brilliant objects with polarized light, but with ordinary illumination show but the faintest sign of rings and a well-developed hilum, at times star-shaped, and at others more like a circular depression. _Rice Starch_ is very similar to that of maize, and is easily confused with it, the grains being about the same size. The grain, however, is distinguished from it by its polygonal form, and its well defined angles, as indicated in Fig. 59. The hilum is more prominent and more often stellate or linear. Several granules are at times united. _Cassava Starch._—This variety of starch is obtained from the root of the sweet cassava, which grows in great profusion in Florida. It is compared with maize starch in Figs. 60 and 61. In the illustration the granules are represented as magnified 150 diameters. The grains of the cassava starch measure about 0.012 millimeter in diameter and resemble very nearly maize starch, except that they have greater evenness of outline.[169] For further descriptions of starch grains the reader is referred to the work of Griffith, already cited. These descriptions, it will be seen, do not agree entirely with those of some other authors, but they are based on a somewhat extensive experience. There are peculiarities of size, shape and appearance of starch granules, which must be allowed for, and the necessity for every investigator to compare a starch which he is desirous of identifying with authentic specimens, must always be recognized. AUTHORITIES CITED IN PART SECOND. [23] Vines, Vegetable Physiology. [24] Berichte der deutschen chemischen Gesellschaft, Band 23, S. 2136; Stone, Agricultural Science Vol. 6, p. 180. Page 59, eighth line from bottom insert “original” before “optical.” Page 60, second line from top, read _d_ instead of _l_ fructose. [25] Herles, Zeitschrift des Vereins für die Rübenzucker-Industrie, 1890. S. 217. [26] Tucker; Wiechmann; Sidersky; von Lippman; Tollens and Spencer. [27] Bulletin No. 28, Department of Agriculture, Division of Chemistry, p. 197. [28] Physikalisch-Chemische Tabellen, S. 42. [29] Tucker’s Manual of Sugar Analysis, pp. 100 et seq. [30] Vid. op. cit. supra, p. 108. [31] Op. cit. supra, p. 109. [32] Op. cit. supra, p. 110. [33] Op. cit. supra, p. 114. [34] Spencer’s Handbook for Sugar Manufacturers, p. 92. [35] Landolt’s Handbook of the Polariscope, pp. 95 et seq. [36] Robb, vid. op. cit. supra, p. 8. [37] Spencer’s Handbook for Sugar Manufacturers, pp. 22 et seq. Tucker’s Manual of Sugar Analysis, pp. 120 et seq. [38] Sidersky; Traité d’Analyse des Matières Sucrées, p. 104. [39] Journal of the American Chemical Society, 1893. Vol. 15, p. 121.