I. Granules throughout many-angled.

(1.) With an evident nucleus, largest 0066 mm.

[00025 inch]-RICE.

(2.) Without a nucleus, the largest 0088 mm. ['00034 inch]-MILLET STARCH.

II. Among many angular forms also some rounded.

(A.) No drum-shaped starches present, angular forms predominating.

(1.) Without a nucleus, very small, 0044 mm. [00016 inch]-OAT STARCH. (2.) With a nucleus, 0132 to 0220 mm. [0005 to 0008 inch].

(a.) Evident round nucleus, here and there the smaller combined, granules in variously shaped groups-BUCKWHEAT.

(b.) Mostly a radiating or star-shaped fissure, none of the granules united— MAIZE.

(B.) More or less numerous drum-shaped to sugar-hat shaped granules.

(1.) Numerous eccentric layers. Largest granules, 0220 to 0352 mm. [0008 to 0014 inch]-BATATA STARCH.

(2.) Without concentric circles, 008 to 022 mm. ['0003 to 0008 inch].

(a.) The slit of the drum-shaped particles enlarged towards the flattened side, 008 to 022 mm. [0003 to 0008 inch]-CASSAVA STARCH.

(b.) Slit wanting or not large.

(aa.) Nucleus small, eccentric, 008 to 016 mm. ['0003 to 0006 inch]PACHYRHIZUS ANGULATUS.

(bb.) Nucleus small, central, or wanting.

(aaa.) Irregular many-angled forms, 009, 008 to 0176 mm. [0003 to '0007 inch]-SECHIUM STARCH (Cucurbitacea).

(bbb.) Only a few angular forms, some with a radiated fissure, '008 to 0176 mm. [0003 to 0007 inch]-CHESTNUT STARCH.

C. Granules Single and Compound, the Majority Egg-shaped and rounded with Eccentric Nucleus and Numerous Concentric Layers, the Compound Masses composed of a Large Granule and one or a few very Small Flattened Drumshaped Bodies.

025 to 066 mm. ['00097 to 0025 inch]-SAGO STARCH.

Karmarsch has determined the maximum size of some of the starches. Karmarsch's values, as well as Wiesner's, are arranged in the following Table (IX.) They differ in a few instances from the dimensions the author has given at pp. 171–175.

AALERS.-Méthode pour essayer la puerté de l'arrowroot. Journ. Pharm. et Chim., 4e serie, 1866, t. iii., p. 217.

BECHAMP.-Compt. Rend., xxxix. 653; xlii. 1210.

DELFFS.-Poggend. Annal., cix. 648; N. Jahrb. Pharm., xiii. 1.

GREENISH, T.-Pharm. Journ. [3], vol. vii., &c.

GUERIN, VARRY.-Ann. Chim. Phys. (2), lvi. 525; lvii. 108; lx. 32; lxi. 66. GUIBOURT.-Ann. Chim. Phys., xl. 183.

HANBURY and FLUCKIGER.

66

"Pharmacologia." Lond. 1874.

HASSALL. Food and its Adulterations."

JONES, H. W.-Pharm. Journ., 1876, p. 23.

JESSEN.-Poggend. Annal., cvi. 497; Journ. Pract. Chem., cv. 65.

MASCHKE, J.-Pract. Chem., lvi. 409; lxi. 1.

MUTER, J.-" Organic Materia Medica." Lond. 1878.

NÄGELL.-Die Starke-Mehlkörner. 1858.

PAYEN.-Ann. Chim. et Phys. (2), liii. 73; lvi. 337; lxi. 355; lxv. 225 (4), iv. 286. Compt. Rend., xiv. 533; xviii. 240; xxiii. 337; xxv. 147;

xlviii. 67.

SCHARLING.-Journ. Pharm. et Chim. [3], 1856, t. ii., p. 246.

TRIPE, I. W.-On the Discrimination of Starches bv Polarised Light. Analyst, 1879, vol. iv., p. 221.

WIESNER-Einleitung in die Technische Mikroscopie. Svo, Wien, 1867.

WHEAT-WHEATEN FLOUR.

§ 82. The wheat cultivated in this country is the Triticum vulgare, of which there are two varieties-the T. æstivum, or summer wheat, and the T. hybernum, or winter wheat. The mean composition of wheat from 250 analyses is as follows [König]:

These analyses do not include Russian wheat. In the central parts of South Russia a wheat is grown which has an amount of nitrogenous substances quite uncommon-the mean of twentyfour analyses giving a percentage of 3.45 nitrogen and 21:56 nitrogenous substances. The mean composition of the ash of

According to the researches of M. Duvivier, of Chartres, the external part of the envelope of the grain is covered with fatty, odorous, and nitrogenous matters, which are in a particular combination, and form on the grain a very tenacious coating-a sort of preservative, and communicating an odour quite sui generis. These substances, which are named cerealin, tritisecaline, &c., are isolated by treating the entire grain with cold ether, and then allowing the ethereal extract to evaporate spontaneously. However, neither the nature nor even the presence of these matters can be considered satisfactorily established, and further investigation seems necessary.

§ 83. Constituents of Flour.-Flour, in the common acceptation of the term, is ground wheat freed from bran.

B

The physical characters which flour should possess are as follows:-It should be an almost perfectly white, fine powder, with only the slightest tinge of yellow; the odour should be sweet, and it should be free from acidity. It should exhibit no trace of bran when pressed smooth with a polished surface; and it should have a certain amount of cohesiveness sufficient to retain for some time any shape impressed upon it by squeezing. The microscopical characters of good flour are: the absence of foreign starches, of fungi, &c., and the pre

sence alone of the elements of ground wheat. ments of the starches.)

Fig. 26 is a representation of the microscopical structure of wheat when a fine section of the seed is made, × 199. a is the cells of the bran; b the cells of the thin cuticle; e the gluten cells; d the starch cells; B, wheat

starch, x 350.

(See pp. 174, 176, and 178, for measure

The chemical composition of ground wheat is represented in the following table, giving the mean of fourteen analyses by Peligot:-*

The percentage of ash from the whole wheat is much higher than that of ordinary flour, the bran containing much ash. Thus, 100 parts of bran contain

Per cent. 13.1

19.3

4.7

55.6

7.3

According to Church, Indian wheat contains from 10.3 to 16·7 per cent. of albuminoids, the average being 13.5 (Food Grains of India).

The analyses of Millon* and Kekulé give the following:

whilst 100 parts of flour, according to Wanklyn, contain

C. O. Sullivan [Journal Chem. Soc., No. ccxxx., Jan. 7, 1882] has described two varieties of starch found in barley, wheat, and rye, under the names of a and ß amylan.

The principles of separation are briefly as follows:-The finely ground grain is freed from sugars, certain albuminoids, and other substances by alcohol (specific gravity 90), the residue is then treated with water at from 35° to 38° for several hours. The solution is filtered and evaporated until it becomes fairly thick. Alcohol of specific gravity 83 to 84 is now added to complete precipitation; the precipitate is purified by repeated treatment with alcohol, and a dry, friable substance obtained which is an impure mixture of a and ẞ amylan.

The substance is purified by (1) treatment with cold water which dissolves out the B amylan, (2) dilute hydrochloric acid which dissolves out traces of mineral matter, and (3) solution in boiling water, filtration, and precipitation by alcohol. By repetition of these processes a snow-white body was obtained which only gave 3 per cent. of ash, and had the percentages of C, H, and O of a starch.

a amylan is nearly insoluble in cold water, it gelatinises in water, and in 2 per cent. solution forms a clear jelly-like fluid. A solution containing 1 per cent. of dry substance has a specific gravity of 1.00396, and in a 200 mm.-tube an optical activity at 15°-5 equal to 1·3, this gives [a] = − 24.

It does not reduce alkaline copper solution, and is converted into dextrose without yielding any of the intermediate products

+ Comptes Rendus, t. 28, p. 40.