ON STARCH. 
259 
Class II.—The concentric rings all but invisible; liilum 
more or less stellate. To this group belong the starches of 
bean, pea, maize, lentil, clari, and nutmeg. The nucleus of 
the Leguminos® is seen usually as along, more or less stellate, 
air-filled black hollow. The rings are rendered visible by 
treatment with chromic acid. The starches from bean, pea, 
and lentil are in shape oval, oblong, and almost identical; 
but pea and bean have stellate liilum, whilst lentil has a long 
depression. The size of bean starch is *00135 inch, of pea 
•00111 to ’00007 inch, and lentil *00111 inch. 
The starch of maize varies in form, round to polyhedral, 
and the size is -00074 inch. 
Class III.—Starches having both the concentric rings and 
liilum invisible in most granules. This important class 
includes wheat, barley, rye, chestnut, acorn, and a variety 
derived from medicinal plants, jalap, rhubarb, senega, &c. 
Wheat starch is extremely variable in size, having from 
•00185 to *00009 inch. The granules are circular, or nearly 
so, and flattened. Polarised light shows a cross but not well 
with water as a medium. 
Barley granules are fairly uniform in size, *00073 in., and 
in form are slightly angular circles. Acorn granules 
•00074 in. diameter, and almost round; eccentricity 
The others call for no special remark, and are distinguished 
chiefly by measurement. 
Class IV.—All the granules truncated at one end. This 
class includes sago, tapioca, and arum, besides several drugs, 
viz. :—belladonna, colchicum, scammony, podophyllum, can- 
ella, aconite, cassia. Sago starch is found in oval ovate 
granules, and *0026 to *00111 in. in size. There is a curved 
liilum at the convex end and rings are faint. Tapioca being 
prepared on hot plates has the starch grains altered from 
their original shape. They appear in groups of two to eight 
granules each, showing a little circle with a broad flat zone 
around it. In form they vary from that of a kettle-drum to a 
sugar loaf, a conical hollow appearing in the nucleus. Size, 
*00074 to *00055 in. Each granule is truncated in one facet. 
Arum starch has two facets. The starches from the medicinal 
plants are similar, but are best distinguished by their 
measurements. 
Class V.—In this class all the granules are angular in 
form. It includes oats, tacca, rice, and pepper, as well as 
ipecacuanha. Oat starch is mostly polyhedral, being irregu¬ 
larly three to six-sided and *00037 in. in size. Bice starch 
has a starred liilum, visible under a power of £ to 
