[Illustration: FIG. 51. SAGO STARCH × 350.] [Illustration: FIG. 52. PEA STARCH × 350.] [Illustration: FIG. 53. BEAN STARCH × 350. DRAWN BY GEO. MARX. A. Hoen & Co., Lithocaustic] [Illustration: FIG. 54. WHEAT STARCH × 350.] [Illustration: FIG. 55. BARLEY STARCH × 350.] [Illustration: FIG. 56. RYE STARCH × 350.] [Illustration: FIG. 57. OAT STARCH × 350.] [Illustration: FIG. 58. INDIAN CORN STARCH × 350.] [Illustration: FIG. 59. RICE STARCH × 350. DRAWN BY Geo. MARX. A. Hoen & Co., Lithocaustic] [Illustration: FIG. 60. CASSAVA STARCH × 150. PLAIN ILLUMINATION.] [Illustration: FIG. 61. INDIAN CORN STARCH × 150. PLAIN ILLUMINATION. A. Hoen & Co., Lithocaustic] _Pea and Bean Starches._—These starches produce but a slight effect with polarized light. The rings are scarcely visible, and the hilum is stellate or much cracked along a median line, the bean more so than the pea, the latter resembling fresh dough kneaded again into the center as in making rolls, and the former the shape assumed by the same after baking. The grains of both are somewhat variable in size, ranging from 0.025 to 0.10 millimeter in length, as shown in Figs. 52 and 53. _Wheat Starch_ grains are quite variable in size, varying from 0.05 to 0.010 millimeter in diameter. They belong to the same class as barley and rye, the hilum being invisible and the rings not prominent. The granules are circular disks in form, and there are now and then contorted depressions resembling those in pea starch. They are the least regular of the three starches named and do not polarize actively. The typical forms of these granules are shown in Fig. 54. _Barley Starch_ is quite similar to that of wheat, but the grains do not vary so much in size, averaging 0.05 millimeter. They have rings which are much more distinct, and very small granules adhering to the largest in bud-like forms, as seen in Fig. 55. _Rye Starch_ is more variable in size, many of the granules not exceeding 0.02 millimeter, while the largest reach 0.06 to 0.07 millimeter. It lacks distinctive characteristics entirely, and is the most simple in form of all the starches. Fig. 56 shows the appearance of the granules under the microscope. _Oat Starch_ is unique, being composed of large compound masses of polyhedral granules from 0.12 to 0.02 millimeter in length, the single granules averaging 0.02 to 0.015 millimeter. It does not polarize actively, and displays neither rings nor hilum. The illustration, Fig. 57, shows its nature with accuracy.