Formerly every baker was his own mealman or miller. This is he case now in Glasgow, and in other parts of Scotland. The bakers buy their own wheat, and manufacture it into flour at their own mills, which are held by them as joint-stock proprietors.

It seems to be generally agreed, that alum in bread is detrimental to the health of those who consume it. The fact, however, is, that the bakers eat the same bread as their customers; and it appears very improbable, that there should be a set of men who knowingly poison themselves. The following is Dr. Ure's opinion upon the effects of alum eaten in bread: -

"The habitual and daily introduction of a portion of alum into the human stomach," says Dr. Ure, in his Dictionary of Chemistry, "however small, must be prejudicial to the exercise of its functions, and particularly to persons of a bilious and costive habit. And, besides, as the best sweet flour never stands in need of alum, the presence of this salt indicates an inferior and highly acescent food, which cannot fail to aggravate dyspepsia, and which may generate a calculus diathesis in the urinary organs."

To ascertain whether alum is present in bread, crumble a portion when somewhat stale into cold distilled water; then squeeze the mass through a piece of cloth, and pass the liquid through a paper filter. A limpid infusion will thus be obtained. A dilute solution of muriate of baryta, dropped into the filtered infusion, will indicate by a white cloud, more or less heavy, the presence and quantity of alum.

It is said, that to counteract the costive quality of alum, when consumed in large quantities, the bakers frequently use jalap in the composition of their bread. This we do not believe. Dr. Darwin says, that when much alum is used, it may be distinguished by the eye in the place where two loaves have stuck together in the oven: they break from each other with a much smoother surface than those which do not contain alum. We believe this to be correct; - indeed the bakers say, that this is one of their reasons for using alum.

When the statute was enacted by king John for regulating the price of bread, and during many of the subsequent statutes of assize, the baker was his own manufacturer, purchasing his own corn, and having it ground and separated into flour, pollard, and bran. According to Pownall's work on the assize of bread, which we have no doubt is correct, this flour, or the flour from which the bran and pollard only are separated, was found, from an unvaried series of experiments made from age to age, through the course of many hundred years, to be three-fourths in weight of the whole grain of wheat, taking all sorts of wheats together; and the bread made from this flour has always been decreed the standard of the food of bread corn. But, by insensible degrees, the manufacture of bread became separated into two distinct employments. To this cause Mr. Edlin attributes the custom - the pernicious custom, as he considers it - of making bread from other flour than that we have described, which many persons assert is more wholesome and more nutritious than that made of the finest flour. The miller not considering himself liable to the assize laws, made different kinds of flour, some of which was extremely fine and white. The bread made of this flour was so very white, and pleasing to the eye and palate, that in the course of a few years it got into general use, and the people, particularly the Londoners, refused to buy the bread made of the whole of the grain, except the husks, or coarse and fine bran.

To this circumstance, perhaps, may be attributed the almost universal use of alum in bakers' bread not made of the finest flour; and very little of it is so made, for it is impossible from a second flour, which is the flour generally used, to make bread white without the employment of the bleaching properties of this ingredient.

The assize of bread has been for some time abolished, and the baker is entitled to sell his bread for as much as anybody is willing to give for it. There is very properly still a heavy penalty attached to selling bread short of weight.

Potatoes, called by the bakers fruit, are used by them for the purpose of aiding the fermentation, and, as they say, for the purpose of improving the appearance of the bread, and not for saving flour. Indeed, in the small quantities in which we have seen them used, not more than seven or eight pounds to two hundred and eighty pounds of flour, there can be little or nothing gained by them. Potatoes, however, as well as damaged rice, are no doubt used in large quantities by cheap, fraudulent bakers. We utterly disbelieve the stories about bakers using ground bones to adulterate bread, for this reason - namely, that the expense of making them fit for such a purpose would be much greater than the cost of flour itself.

There are instances on record of convictions having been obtained against bakers for using gypsum, chalk, and pipe-clay, in the manufacture of bread.

Carbonate of ammonia, which is sometimes used by bakers in producing light and porous bread from sour or damaged flour, does not appear to be liable to the same objections as those urged against alum; as the action of the former upon the bread is merely mechanical, no part of this salt remaining in bread after it is baked. During the operation of baking, it causes the dough to swell up into air bubbles, which carry before them stiff dough, and thus it renders the dough porous; the salt itself is at the same time totally volatilized, and not a particle remains in the bread. Carbonate of ammonia, however, has not, like alum, the property of bleaching the bread.

It is said, that the carbonate of magnesia of the shops, when well mixed with flour in the proportion of twenty to forty grains to a pound of flour, materially improves it for the purpose of making bread. It is recommended to be employed when the flour is new, or of a bad quality. Mr. Davy, professor of Chemistry, says, that this substance must be most intimately mixed with the flour, previous to laying the sponge; and gives it as his decided opinion, that not the slightest danger can be apprehended from the use of so innocent a substance, in such small quantities as he recommends.