Group IV: More or less truncated at one end.
| Name. | Shape. | Normal measurements. | Remarks. |
|---|---|---|---|
| Cassia | Round | 0.00111 to 0.00018 | Round or muller shaped granules and faint circular hilum. |
| Cinnamon | Like cassia | 0.00074 to 0.00009 | More frequently truncated than cassia, and smaller. |
| Sago (raw) | Oval-ovate | 0.00260 to 0.00111 | Has circular hilum at convex end and rings faintly visible. |
| Sago (prepared) | ” | 0.00260 to 0.00111 | Has a large oval or circular depression, covering one-third nearly of each granule. |
| Tapioca | Roundish | 0.00074 to 0.00055 | A little over fifty per cent truncated by one facet, and a pearly hilum. |
| Arum | Like tapioca | About 0.00056 | Smaller than tapioca and truncated by two facets. |
| Belladonna | do. | Not distinguishable from tapioca. | |
| Colchicum | do. | About 0.00074 | Larger than tapioca, and contains many more truncated granules. |
| Scammony | do. | ” 0.00045 | Smaller than tapioca, more irregular, and hilum not visible. |
| Cancella | Very variable | 0.00033-0.00022 | Very variable, form and small size the only points. |
| Podophyllum | Like tapioca | About 0.00040 | Like scammony, but has visible hilum in most of the granules. |
| Aconite | do. | ” 0.00037 | Like tapioca, but half the size. |
Group V: All granules more or less polygonal.
| Name. | Shape. | Normal measurements. | Remarks. |
|---|---|---|---|
| Tacca | Poly- or hexagonal | 0.00075 to 0.00037 | Distinguished from maize by its sharp angles. |
| Oat | Polygonal | About 0.00037 | Larger than rice and hilum visible in some granules. |
| Rice> | do. | 0.00030-0.00020 | Measurement using one-eighth or one-twelfth inch power, and then hilum visible. |
| Pepper | do. | 0.00020-0.00002 | Do. |
| Ipecacuanha | do. | About 0.00018 | Some round and truncated granules, adhering in groups of three. |
199. Blyth’s Classification.—Blyth gives the following scheme for the identification of starch granules by their microscopic appearance.[165]
Division I.—Starches showing a play of colors with polarized light and selenite plate:
The hilum and concentric rings are clearly visible, and all the starch granules, oval or ovate. Canna arrowroot, potato, arrowroot, calumba, orris root, ginger, galangal and turmeric belong to this division.
Division II.—Starches showing no iridescence, or scarcely any, when examined by polarized light and selenite: