Part 21

+--------------+-------------+------------------------ 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.[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_:

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.[166] The reader can find excellent photomicrographs of the more common starches in Griffith’s book.[167]

=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.

=202. Description Of Typical Starches.=—The more commonly occurring starches are described by Richardson as they appear under the microscope magnified about 350 diameters.[168]

The illustrations, with the exception of the cassava starch, and the maize starch accompanying it were drawn by the late Dr. Geo. Marx from photographs made by Richardson in this laboratory. The two samples excepted were photographed for the author by Dr. G. L. Spencer.

_Maranta Starch._—Of the same type as the potato starch are the various arrowroots, the only one of which commonly met with in this country being the Bermuda, the starch of the rhizome of _Maranta arundinacea_, and the starch of turmeric.

The granules are usually not so varied in size or shape as those of the potato, averaging about 0.07 millimeter in length as may be seen in Fig. 48. They are about the same size as the average of the potato, but are not often found with the same maximum or minimum magnitude, which circumstance, together with the fact that the end at which the nucleus appears is broader in the maranta and more pointed in the potato, enables one to distinguish the two starches without difficulty. With polarized light the results are similar to those seen with potato starch, and this is a ready means of distinguishing the two varieties, by displaying in a striking way the form of the granule and position of the hilum.

_Potato Starch._—The starch grains of the potato are very variable in size, being found from 0.05 to 0.10 millimeter in length, and in shape from oval and allied forms to irregular and even round in the smallest. These variations are illustrated in Fig. 49, but the frequency of the smaller granules is not as evident as in some other cases. The layers are visible in some granules with great distinctness and in others hardly at all, being rather more prominent in the starch as obtained from a freshly cut surface. The rings are more distinct, too, near the hilum or nucleus, which in this, as in all tuberous starches, is eccentric, shading off toward the broader or more expanded portion of the granule. The hilum appears as a shadowy depression, and with polarized light its position is well marked by the junction of the arms of the cross. With polarized light and a selenite plate a beautiful play of colors is obtained. The smaller granules, which are nearly round, may readily be confused with other starches, but their presence serves at once to distinguish this from maranta or Bermuda arrowroot starch. Rarely compound granules are found composed of two or three single ones each with its own nucleus.

_Ginger Starch._—This starch is of the same class as those from the potato and maranta and several others which are of underground origin. In outline the granules are not oval like those named, but more rectangular, having more obtuse angles in the larger ones and being cylindrical or circular in outline in the smaller, as indicated in Fig. 50. They average nearly the same size as maranta starch, but are much more variable, both in size and form. The rings are scarcely visible even with the most favorable illuminations.

_Sago Starch._—This exists in two modifications in the market; as raw and as prepared sago. In the prepared condition it is characterized by a larger circular depression in the center of most of the granules. The rings are not visible. They are mostly circular in form or approaching it, and vary from 0.025 to 0.065 millimeter in diameter, as indicated in Fig. 51.

_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.

_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.

[40] Comptes rendus, 1879. Seance du 20th Octobre 1879; Dingler’s polytechniches Journal, Band 223, S. 608.

[41] Landolt’s Handbook of the Polariscope. p. 120.

[42] Sidersky; Traité d’Analyse des Matières Sucrées, p. 97.

[43] Manual of Sugar Analysis, pp. 143 et seq.

[44] Landolt und Börnstein, Physikalisch-Chemische Tabellen. S. 460.

[45] Bulletin No. 31. Department of Agriculture, Division of Chemistry, p. 232.

[46] Zeitschrift des Vereins für die Rübenzucker-Industrie. 1870, S. 223.

[47] Tucker’s Manual of Sugar Analysis, p. 164.

[48] (bis). Gerlach, Spencer’s Handbook for Sugar Manufacturers, p. 91.

[49] Vid. op. cit. supra, p. 45.

[50] Vid. loc. et op. cit. supra.

[51] Gill; Journal of the Chemical Society, Vol. 24, 1871, p. 91.

[52] Wiley; American Chemical Journal, Vol. 6, p. 289.

[53] Vid. op. cit. supra, p. 301.

[54] Zeitschrift des Vereins für die Rübenzucker-Industrie, 1890. S. 876.

[55] Weber and McPherson; Journal of the American Chemical Society. Vol. 17, p. 320; Bulletin No. 43. Department of Agriculture, Division of Chemistry, p. 126.

[56] Zeitschrift des Vereins für die Rübenzucker-Industrie, 1888, S. 51.

[57] Vid. op. cit. supra, Ss, 699 und 763; 1890. S. 217.

[58] Bulletin de l’Association des Chimistes de Sucrerie et de Distillerie, May, 1890, p. 431.

[59] Neue Zeitschrift für Rübenzucker-Industrie, Band 19, S. 71.

[60] Journal of the Chemical Society, Transactions, Vol. 57, pp. 834, et seq.

[61] Op. cit. supra, p. 866.

[62] Op. cit. supra, 1891, p. 46.

[63] Neue Zeitschrift für Rübenzucker-Industrie, Band 19, S. 71.

[64] From γῦρος and δῦνᾶτός (δύνᾶμις).

[65] Landolt’s Handbook of the Polariscope, p. 125.

[66] Vid. op. cit. supra, pp. 48 et seq.

[67] Berichte der deutschen chemischen Gesellschaft, 1877, S. 1403.

[68] Die landwirtschaftlichen Versuchs-Stationen, Band 40, S. 307.

[69] Spencer’s Handbook for Sugar Manufacturers, p. 80; Landolt’s Handbook of the Polariscope, p. 216; Tollens’ Handbuch der Kohlenhydrate.

[70] Annalen der Chemie and Pharmacie, May, 1870.

[71] Tucker’s Manual of Sugar Analysis, p. 208.

[72] Rapport fait a la Société d’Encouragement d’Agriculture; Journal de Pharmacie et de Chimie, 1844. 3d serie, Tome 6, p. 301.

[73] Annalen der Chemie und Pharmacie, Band 39, S. 361.

[74] Jahrbücher für praktische Heilkunde, 1845, S. 509.

[75] Archives für Physiologische Heilkunde, 1848, Band 7, S 64.

[76] Rodewald and Tollens; Berichte der deutschen chemischen Gesellschaft, Band 11, S. 2076.

[77] Chemical News, Vol. 39, p. 77.

[78] The Analyst, Vol. 19, p. 181.

[79] Gaud; Bulletin de l’Association des Chimistes de Sucrerie et de Distillerie, Apr. 1895, p. 629; Comptes rendus, 1894, Tome 119, p. 604.

[80] Annalen der Chemie und Pharmacie, B. 72, S. 106.

[81] Journal of Analytical and Applied Chemistry, Vol. 4, p. 370.

[82] Wiley; Bulletin de l’Association des Chimistes de Sucrerie et de Distillerie, April, 1884.

[83] Vid. op. cit. supra, 1895, p. 642; Comptes rendus, Tome 119, 1894, p. 650.

[84] Annual Report, United States Department of Agriculture, 1879, p. 65; Zeitschrift für Analytische Chemie, Band 12, S. 296; Mohr Titrirmethode, sechste auflage, S. 508.

[85] Comptes rendus, 1894, Tome 119, p. 478.

[86] Gazetta Chimica Italiana, Tome 6, p. 322.

[87] Sidersky; Traité d’Analyse des Matières Sucrées, p. 148.

[88] Vid. op. cit. supra, p. 149.

[89] Neue Zeitschrift für die Rübenzucker-Industrie, Band 22, S. 220.

[90] Zeitschrift des Vereins für Rübenzucker-Industrie, 1889, S. 933.

[91] Vid. op. cit. supra, 1887, S. 147.

[92] Berichte der deutschen chemischen Gesellschaft, Band 23, No. 14, S. 3003; Zeitschrift des Vereins für die Rübenzucker-Industrie, 1891, S. 97.

[93] Ost; vid. op. et loc. cit. supra.

[94] Zeitschrift des Vereins für die Rübenzucker-Industrie, 1890, S. 187.

[95] Chemical News, Vol. 39, p. 77.

[96] The Analyst, 1894, p. 181.

[97] Chemical News, Vol. 71, p. 235.

[98] Journal de Pharmacie et de Chimie, 1894, Tome 30, p. 305.

[99] Pharmaceutical Journal, (3), 23, p. 208.

[100] Vid. op. cit. supra, (3), 25, p. 913.

[101] Sidersky; Bulletin de l’Association des Chimistes, Juillet, 1886 et Sept. 1888.

[102] Bodenbender and Scheller; Zeitschrift des Vereins für die Rübenzucker-Industrie, 1887, S. 138.

[103] Vid. op. cit. supra, 1889, S. 935.

[104] Ewell; Manuscript communication to author.

[105] Journal für praktische Chemie, 1880, Band 22, 46; Handbuch der Spiritusfabrication, 1890, S. 79; Zeitschrift des Vereins für die Rübenzucker-Industrie, 1879, S. 1050; _Ibid_, 1883, S. 769; _Ibid_, 1889, S. 734.

[106] Handbuch der Spiritusfabrication, 1890, 79.

[107] Wein; Tabellen zur quantitativen Bestimmung der Zuckerarten, S. 13. (The caption for the table on page 159 should read as on page 160.)

[108] Zeitschrift des Vereins für die Rübenzucker-Industrie, 1889, S. 735.

[109] Bulletin No. 43, Department of Agriculture, Division of Chemistry, p. 209.

[110] Chemiker-Zeitung, 1893, S. 548.

[111] Wein; Tabellen zur quantitativen Bestimmung der Zuckerarten, S. 35.

[112] Berichte der deutschen chemischen Gesellschaft, Band 16, S. 661.

[113] Vid. op. cit. supra, Band 22, S. 87.

[114] Chemisches Centralblatt, 1895, Band 2, S. 66.

[115] Comptes rendus; Tome 112, No. 15, p. 799.

[116] Vid. op. cit. supra, Tome 94, p. 1517.

[117] Journal of the Chemical Society, June, 1888, p. 610. (In the formulas for lactose and arabinose read H₂₂ and H₁₀ respectively.)

[118] American Chemical Journal, Vol. 11, No. 7, p. 469.

[119] Chemisches Centralblatt, 1889, No. 7.

[120] American Chemical Journal, Vol. 17, No. 7, pp. 507, 517.

[121] Comptes rendus, Tome 118, p. 426.

[122] Justus Liebig’s Annalen der Chemie, 1890. Band 257, S. 160.

[123] Journal of Analytical and Applied Chemistry, Vol. 7, pp. 68 et seq.

[124] Flint and Tollens; Berichte der deutschen chemischen Gesellschaft, Band 25, S. 2912.

[125] Vid. op. cit. supra, Band 23, S. 1751. (Read Günther.)

[126] Journal of Analytical and Applied Chemistry, Vol. 5, p. 421.

[127] Vid. op. cit. supra, p. 426.

[128] Berichte der deutschen chemischen Gesellschaft, Band 24, S. 3575.

[129] Journal of Analytical and Applied Chemistry, Vol. 7, p. 74.

[130] Chemiker-Zeitung, Band 17, 1743.

[131] Vid. op. cit. supra, Band 18, N. 51, S. 966.

[132] Monatshefte für Chemie, Band 16, S. 283; Berichte der deutschen chemischen Gesellschaft, Referate Band 28, S. 629.

[133] Papasogli; Bulletin de l’Association des Chimistes de Sucrerie et de Distillerie, Juillet 1895, p. 68.

[134] Gans und Tollens; Zeitschrift des Vereins für die Rübenzucker-Industrie, Band 38, S. 1126.

[135] Berichte der deutschen chemischen Gesellschaft, 20, S. 181; Zeitschrift des Vereins für die Rübenzucker-Industrie, 1891, S. 895.

[136] Zeitschrift des Vereins für die Rübenzucker-Industrie, 1891, S. 891.

[137] Chemiker-Zeitung, 1888, No. 2; Zeitschrift des Vereins für die Rübenzucker-Industrie, 1888, S. 347.

[138] Fischer; Berichte der deutschen chemischen Gesellschaft, Band 20, S. 821; Band 21, Ss. 988; 2631.

[139] Zeitschrift für physiologische Chemie, Band 11, S. 492.

[140] Vid. op. cit. supra, Band 12, No. 4, Ss. 355 et seq; No. 5, Ss. 377 et seq.

[141] Berichte der deutschen chemischen Gesellschaft, Band 20, S. 540.