Good =wheat flour= ought to be white, not gritty or lumpy, not acid or musty, forming a coherent stringy dough. Examined microscopically, it should show the absence of any fungi, or acarus farinæ, or of foreign starches, such as barley, maize, rice, potato, known by the different shape of their starch granules. (See Fig. 1.) Alum has been occasionally added to flour, to enable the baker to make a white and porous bread from damaged wheat flour. It can be detected as follows:—Pour over the freshly cut surface of a slice of bread some freshly prepared decoction of logwood chips, and then a solution of carbonate of ammonia. If alum is present, the bread turns a marked blue to violet colour; but if the bread is pure, it is only stained pink. The wheat grain may be used as food in its entirety. Thus boiled in milk, after having been soaked in water, it forms the chief constituent of _frumenty_. Usually it is converted into flour by grinding or milling. A grain of wheat consists of three parts, an outer envelope, the _bran_, consisting chiefly of indigestible cellulose, and composing 13½ per cent. of the grain; the kernel, or _endosperm_, which makes up 85 per cent. of the grain; and the _germ_, forming 1½ per cent. of the grain. In the old method of stone grinding, the bran was removed, and the germ left along with the endosperm. In the elaborate processes of modern roller milling, the bran is removed as in the old grinding, because it cannot without the greatest difficulty be reduced to powder; and the germ is also removed, because the oil abundantly present in it is apt to become rancid and spoil the flour, and because the soluble proteids in it are apt to change some of the flour into dextrin and sugar, which become brown in baking and spoil the appearance of the bread. The germ is easily removed, because its toughness causes it to be flattened out in the milling, while the endosperm becomes powdery. The central part of the endosperm is the source of ‘patents.’ It is very rich in starch and is used for making fancy breads and pastry. The outer part of the endosperm is ‘households.’ ‘Households flour’ is subdivided into (_a_) second patents, or ‘whites’; (_b_) first households; (_c_) second households or ‘seconds.’ ‘Seconds’ is richest in gluten, ‘whites’ in starch. Ordinary bread is normally derived from a blend of these three. Some ‘strong’ wheats, _e.g._ Australian, yield a ‘patents’ which is rich in gluten, and such flour is used for making Vienna bread. ‘Strong’ wheats take up most water in baking, and so yield most loaves per sack. ‘Seconds’ flour yields a bread which is richer in proteid than most other kinds; but the dark colour of the loaf makes it unpopular. Various schemes have been devised to utilise the germ and the bran, which are ordinarily discarded. In the preparation of _Hovis flour_ the separated germ is partially cooked by superheated steam. This kills the ferment contained in the soluble proteids, and thus prevents it from