Spec. Plant. Willd. i. 476.

Cl. 3. Ord. 2. Triandria Monogynia. Nat. ord. Graminaceae.

G. 152. Calyx two-valved, solitary, subtriflorous. Flower somewhat obtuse.

* Annual.

Species 2. Triticum hybernum 1, Winter Wheat. Gaertner de Fructibus.

Officinal. Farina. Amylum, Lond. Edin. Triticum; semi-num farina, Dub. Wheat flour. Starch.

Syn. Farine du froment, Amidon (F.), Weitzenmehl, Kraftmehl, Staerhe (G.), Abgoon (Arab.), Neshaste (Pers.) Geeboonkaheer (H.), Farina di Fru-mento l'Amido (I.), Acemite, almidon (S), Godumbay mao (Tarn.), Imno (Begharmi).

The country whence this valuable grain originally came is unknown; but it is certain that Sicily was the part of Europe where it was first cultivated. It will not vegetate beyond the 62° of northern latitude. It has two sets of roots; one set proceeding directly from the seed, and the other from what is denominated the corona of the plant, about two inches above the first: the coronal roots do not shoot till spring-time, and collect more nutriment than the seminal roots 2; the ears or spikes are long, with the grain lodged in four rows, and imbricate : the chaff smooth, bellied, and terminated by very short awns, distinguishing it from spring wheat (triticum aestivum) which has awns three inches long. Many varieties of wheat are cultivated in this country, of which the white Dantzic is considered the best. The grain is small and translucent, and yields flour which makes more bread in proportion to the quantity of flour than that of any other variety of wheat. After the operation of grinding, the farinaceous part of the seed is separated, by means of cloth sieves, into several distinct portions, of various degrees of fineness: but the whole may be resolved into two: 1. flour, which constitutes more than two thirds of the whole; and, 2. bran, which consists chiefly of the husks of the seed.

Starch is manufacured by steeping either entire or coarsely bruised wheat in cold water, until it swells, and yields a milky juice when squeezed. It is then subjected to pressure in coarse bags placed in vats filled with water; and when all the milky juice is obtained, the bags are removed, and the fecula deposits itself. In a short time the supernatant liquor ferments, and alcohol and acetic acid are formed in it. The whole is now put into tubs called frames, in which the impure fecula is allowed to subside: and after the water is poured off, the upper part of the sediment which last subided being dirty and discoloured, is scraped off from the starch below; this is then repeatedly well washed, pressed in cloths, and dried by a gentle heat, during which it cracks into small columnar masses, and is the finest white starch of the shops.1

Dloscoridis. 2 Hunter's Georgical Essays, Essay v.

Qualities. - Flour is inodorous and nearly insipid. Water with which it has been macerated acquires an opaline colour and a sweetish taste; affords precipitates with infusion of galls and the strong acids, and rapidly becomes sour. It appears to contain gluten, sugar, gum, albumen, and phosphate of lime: besides fecula or starch that remains insoluble. According to Vogel, the constituents of flour are, in 100 parts fecula 68, gluten 24, saccharine gum 5, albumen 1.50. The action of these principles on each other, when flour is kneaded with water, and yeast added to the mass, excites the panary fermentation, and produces bread, a little salt being added to give it sapidity. The large proportion of gluten in wheat flour renders it fitter for this purpose than any other kind of flour. During the process, a large quantity of carbonic acid gas is evolved, which swells up the mass, and gives it the spongi-ness and lightness that characterize well-baked bread.2 For the purpose of baking bread a heat of 488° is required. When flour has been long kept, it becomes musty, and undergoes the putrefactive fermentation, in which state the bread made with it is very unwholesome.

Flour is fit for making bread only when all its constituents are entire; and as gluten is the most susceptible of decomposition among them, the ascertaining its presence is a proof of the goodness of the flour. M. Taddei has taught us that guiaic is a test of the presence of gluten, by striking with it a beautiful blue colour: flour, therefore, which exhibits this colour when rubbed with guiaic and a few drops of vinegar, may be pronounced good.

Starch is inodorous and insipid: in white columnar masses which are easily reduced to powder. It is insoluble in alcohol, ether, and cold water; but in the latter it falls into powder. Boiling water dissolves it, forming an insipid, inodorous, semi-transparent, opaline, gelatinous-like paste, which becomes brittle and opaque, when spread out in a dry air: but when exposed, without being spread out, it separates into a watery fluid, and an opaque paste; sours, and becomes mouldy. Alcohol precipitates starch white and tough from its solutions; acetate of lead and infusion of galls also throw it down, but the precipitate formed by the latter is redissolved by heating the liquid to 120°. Although potassa dissolves starch, yet the solution of it is not altered by potassa, carbonate of potassa, nor ammonia; but a solution of potassa in alcohol, and a solution of sulphuret of potassa in alcohol, both produce precipitates. From the produce obtained from distilling starch per se, it appears to be a ternary compound of carbon, oxygen, and hydrogen.

1 The ordinary blue starch, which is coloured with a solution of smalt and alum in water, is unfit for medicinal uses. The Chians first made starch.

2 The method of making leavened bread was probably invented by the Egyptians; for it appears that the Israelites were acquainted with it after they sojourned in Egypt, but not before. It was known to the Greeks during the Trojan war, but the use of yeast or barm was discovered by the ancient Gauls.

Medical properties and uses. - The utility of bread as an article of diet requires no particular notice. As a medicinal agent it is used for forming poultices, cataplasms, and for giving bulk and form to very active medicines which require to be given in minute doses, in the solid state, or as pills. When toasted and infused in water, it gives a pleasant flavour to the fluid, and renders it more acceptable as a diluent in febrile diseases, and as the ordinary beverage of the dyspeptic. Starch is less nutritive than bread, but is, perhaps, more digestible. It forms the greater part of the nutritive matter of the different farinaceous substances which are in general use as the diet of the sick, such as sago'2, salep3, tapioca4, arrowroot5, and gruel, which are only different modifications of

1 Wheat flour is almost exclusively used for this purpose in England, part of Scotland, France, a part of Germany, Hungary, the Crimea and Caucasus, and some part of the middle of Asia. It is used also for the same purpose, but not so exclusively, in Spain, Portugal, Italy, Greece, Persia, Northern India, Arabia, Egypt, Nubia, Barbary, the Canary Islands, North America, the Brazils, Buenos Ayres, Chili, the Cape of Good Hope, and the temperate zone of New Holland. Rye, barley, and oats, usurp its place in many parts of the North of Europe; rice in the East Indies, China and Japan, in Asia and Africa, in the torrid zone; and maize in part of America and of Africa. Beside these grains, yams, casava, batatas, the banana, doura (singhum), sago, the bread-fruit, some species of arum, chenopodium, quinoa, acrastichum furtum, and arachis hypogcea, are used in different parts of the globe as substitutes for bread. Schouw on the Geographic Distribution of the Graminae.

2 Sago is the pith of various species of palms. One of these, the sagu-tree of Asia, Metroxylon sagu (Roxburgh), when fifteen years old will sometimes yield 600 weight of Sago. It has been calculated, that one English acre of land will grow 435 sagu trees; which would yield 120,500 lbs. avoirdupois of sago, or 8000 lbs. yearly; a produce triple that of wheat. Hist, of the Ind. Archip. i. p. 357.

3 Salep is prepared from the bulbs of the Orchis mascula. The bulbs are first dipped in hot water and the skin rubbed off; after which, they are placed on a tin plate, and put into a heated oven for ten minutes, and, lastly, dried in the sun. By this process, they acquire the appearance of horn, and, when pulverized, form the salep of the shops.

4 Tapioca is prepared from the roots of the Iatropha manihot. The roots are first freed from the rind : and then, are either held to a large wheel, which, on being turned round, soon reduces them to a fine pulp, or they are grated. The pulp is next put into bags, and pressed, to squeeze out the moisture, which contains a poisonous principle, and afterwards repeatedly washed. It is then pressed through plates full of round holes to granulate it; and, lastly, dried by means of heat in large flat pans.

5 Arrow-root is the fecula of the tubers of Maranta arundinacea. The powder is prepared from roots of a year old, which, after being well worked, are beaten, starch. The solution of starch is employed medicinally as a demulcent; but as it is very readily acted on by the stomach, it cannot be of much service in involving acrid matters in the intestines when taken by the mouth. In the form of enema, however, it is often and advantageously used for allaying the effects of acrid bile on the coats of the rectum in bilious diarrhoea and dysentery; and for sheathing the rectum in cases of abrasion, and inflammation of the gut. It is the common vehicle for the exhibition of opium per anum.

Officinal preparations. - Mucilago Amyli, E. D. Cataplasma fermenti cerevisiae, D.