Part 35

I. Granules entirely angular. 1. Many with prominent nucleus: At most 0.0066 mm, rice starch: 2. Without a nucleus: The largest 0.0088 mm, millet starch:

II. Among the many-angled also rounded forms. a. No drum-shaped forms present, angular form predominating. 1. Without nucleus or depression very small; 0.0044 mm, oat starch: 2. With nucleus or depression; 0.0132-0.0220 mm. a. Nucleus or its depression considerably rounded; here and there the granules united into differently formed groups; buckwheat starch: b. Nucleus mostly radiate or star-shaped; all the granules free; maize (corn) starch:

b. More or less numerous kettledrum and sugar-loaf like forms. 1. Very numerous eccentric layers; the largest granules 0.022-0.0352 mm, batata (sweet potato) starch: 2. Without layers or rings; 0.008-0.022 mm. a. In the kettledrum-shaped granules the nucleal depression mostly widened on the flattened side; 0.008-0.022 mm, cassava starch: b. Depression wanting or not enlarged. aa. Nucleus small, eccentric; 0.008-0.016 mm, pachyrhizus starch: bb. Nucleus small, central, or wanting. aaa. Many irregular angular forms; 0.008-0.0176 mm, sechium starch: bbb. But few angular forms; some with radiate, nucleal fissure; 0.008-0.0176 mm, chestnut starch.

C. Granules simple and compound; predominant forms, oval, with eccentric nucleus and numerous layers; the compound granule made up of a large granule and one or more relatively small kettledrum-shaped ones; 0.025-0.066 mm, sago starch.

=198. Muter’s Table for the Detection of Starches when Magnified about 230 Diameters.=

Group I: All more or less oval in shape and having both hilum and rings visible.

-------------+----------------+-------------+----------------------- Name. | Shape. | Normal | Remarks. | |measurements.| -------------+----------------+-------------+----------------------- Tous les mois|Oval, with flat | 0.00370 |Hilum annular, near one | ends | to 0.00185 | end and incomplete | | | rings. | | | Potato |Oval | 0.00270 |Hilum annular, rings | | to 0.00148 | incomplete, shape and | | | size very variable. | | | Bermuda |Sack-shaped | 0.00148 |Hilum distinct annular, arrowroot | | to 0.00129 | shape variable, rings | | | faint. | | | St. Vincent |Oval-oblong | 0.00148 |Hilum semi-lunar, rings arrowroot | | to 0.00129 | faint, shape not very | | | variable. | | | Natal |Broadly ovate | 0.00148 |Hilum annular, in arrowroot | | to 0.00129 | center and well marked | | | complete rings. | | | Galangal |Skittle-shaped |About 0.00135|Hilum elongated, very | | | faint incomplete | | | rings. | | | Calumba |Broadly | ” 0.00185|Hilum semi-lunar, faint | pear-shaped | | but complete rings, | | | shape variable. | | | Orris root |Elongated-oblong| ” 0.00092|Hilum faint, shape | | | characteristic. | | | Turmeric |Oval-oblong, | ” 0.00148|Very strongly marked | conical | | incomplete rings. | | | Ginger |Shortly conical,| ” 0.00148|Hilum and rings | with rounded | | scarcely visible, | angles. | | shape variable but | | | characteristic. -------------+----------------+-------------+-------------------------

Group II: With strongly developed hilum more or less stellate.

-------------+--------------+-------------+------------------------- Name. | Shape. | Normal | Remarks. | |measurements.| -------------+--------------+-------------+------------------------- Bean |Oval-oblong |About 0.00135|Fairly uniform. | | | Pea |Like bean | 0.00111 |Very variable in size, | | to 0.00074 | with granules under | | | 0.00111 preponderating. | | | Lentil |Like bean |About 0.00111|Hilum, a long depression | | | seldom radiate. | | | Nutmeg |Rounded | ” 0.00055|The small size and | | | rounded form | | | distinctive. | | | Dari |Elongated | ” 0.00074|Irregular appearance and | hexagon | | great convexity | | | distinctive. | | | Maize |Round and | ” 0.00074|The rounded angles of the | polygonal | | polygonalgranules | | | distinctive. -------------+--------------+-------------+-------------------------

Group III: Hilum and rings practically invisible.

-------------+--------------+-------------+------------------------- Name. | Shape. | Normal | Remarks. | |measurements.| -------------+--------------+-------------+------------------------- Wheat |Circular and | 0.00185 |Very variable in size and | flat | to 0.00009 | very dull polarization | | | in water. | | | Barley |Slightly |About 0.00073|The majority measuring | angular | | about 0.00373 | circles | | distinctive, and a few | | | four times this size. | | | Rye |Like barley | 0.00148 |Small granules, quite | | to 0.00009 | round, and here and | | | there cracked. | | | Jalap |Like wheat | |Polarizes brightly in | | | water. | | | Rhubarb | do. | 0.00055 |Polarizes between jalap | | to 0.00033 | and wheat, and runs | | | smaller and more convex. -------------+--------------+-------------+------------------------- Senega |Like wheat | 0.00148- | | | 0.00009 | Bayberry | do. | 0.00074- | Measurements the | | 0.00011 | only guide. Sumbul | do. | 0.00074- | | | 0.00009 | -------------+--------------+-------------+------------------------- Chestnut |Very variable | 0.00090- |Variable form, and small | | 0.00009 | but regular size, | | | distinctive. | | | Acorn |Round-oval |About 0.00074|Small and uniform size, | | | distinctive. | | | Calabar bean |Oval-oblong | 0.00296 |Large size and shape | | to 0.00180 | characteristic. | | | Licorice |Elongated-oval|About 0.00018|Small size and shape | | | distinctive. | | | Hellebore |Perfectly | 0.00037 |Small, regular size and (green or | rotund | to 0.00009 | rotundity, distinctive. black) | | | | | | Hellebore |Irregular | 0.00055 |Irregular shape and faint (white) | | to 0.00009 | central depression, | | | distinctive. -------------+--------------+-------------+-------------------------

Group IV: More or less truncated at one end.

-------------+--------------+-------------+------------------------ Name. Shape. | Normal | Remarks. | |measurements.| -------------+--------------+-------------+------------------------ Cassia |Round | 0.00111 |Round or muller shaped | | to 0.00018 | granules and faint | | | circular hilum. | | | Cinnamon |Like cassia | 0.00074 |More frequently truncated | | to 0.00009 | than cassia, and | | | smaller. | | | Sago (raw) |Oval-ovate | 0.00260 |Has circular hilum at | | to 0.00111 | convex end and rings | | | faintly visible. | | | Sago | ” | 0.00260 |Has a large oval or (prepared) | | to 0.00111 | circular depression, | | | covering one-third | | | nearly of each granule. | | | Tapioca |Roundish | 0.00074 |A little over fifty per | | to 0.00055 | 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- |Very variable, form and | | 0.00022 | 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 | Remarks. | |measurements.| -------------+--------------+-------------+------------------------- Tacca |Poly- or | 0.00075 |Distinguished from maize | hexagonal | to 0.00037 | by its sharp angles. | | | Oat |Polygonal |About 0.00037|Larger than rice and | | | hilum visible in some | | | granules. | | | Rice | do. | 0.00030- |Measurement using | | 0.00020 | one-eighth or | | | one-twelfth inch power, | | | and then hilum visible. | | | Pepper | do. | 0.00020- | Do. | | 0.00002 | 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.

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:

Class I.—The concentric rings are all but invisible, and the hilum stellate. The bean, pea, maize, lentil, dari and nutmeg starches are in this class.

Class II.—Starches which have both the concentric rings and hilum invisible in the majority of granules: this important class includes wheat, barley, rye, chestnut, acorn, and many starches in medicinal plants.

Class III.—All the granules are truncated at one end. This class includes sago, tapioca and arum, several drugs and cinnamon and cassia.

Class IV.—In this class all the granules are angular in form and it includes oats, tacca, rice, pepper and ipecacuanha.

=200. Preparation of Starches for Microscopical Examination.=—The approximately pure starches of commerce may be prepared for microscopic examination by rubbing them up with water and mounting some of the suspended particles by one of the methods to be described below.

In grains, seeds and nuts the starch is separated by grinding with water and working through fine linen. The starch which is worked through is allowed to subside, again beaten up with water if necessary and the process continued until the grains are separated sufficiently for microscopic examination. A little potash or soda lye may be used, if necessary, to separate the granules from albuminous and other adhering matter. The analyst should have a collection of samples of all common starches of known origin for purposes of comparison.

The granules are mounted for examination by plain light in a medium of glycerol and camphor water. When polarized light is used the mounting should be in Canada balsam. The reader can find excellent photomicrographs of the more common starches in Griffith’s book.

=201. Appearance in Balsam with Polarized Light.=—Mounted in balsam the starches are scarcely visible under any form of illumination with ordinary light, the index of refraction of the granules and the balsam being so nearly alike. When, however, polarized light is used the effect is a striking one. It is very easy to distinguish all the characteristics, except the rings, the center of the cross being at the nucleus of the granule.

With the selenite plate a play of colors is produced, which is peculiar to some of the starches and forms the basis of Blyth’s classification.