It is commonly agreed that bread, in the usual acceptation of the term, should contain nothing but flour, yeast, salt, and water; or if other things are present they should consist only of the products formed by the interaction of these four substances in the process of baking. Millers and bakers have, however, found by experience that the addition of certain substances to the flour or to the dough may sometimes enable them substantially to improve the market value of the bread produced by certain flours. The possible good or bad effect of such additions on the public health will be discussed in a later chapter. It may be of interest here to mention some of the substances which are commonly used as flour or bread improvers by millers and bakers, and to discuss the methods by which they effect their so called improvements. In a former chapter we have discussed the quality of wheat from the miller’s point of view, and during the discussion certain views were enunciated on the subject of strength. It was pointed out that a strong flour was one which would make a large well-shaped loaf, and that the size of the loaf was dependent on the flour being able to provide sugar for the yeast to feed upon right up to the moment when the loaf goes into the oven. This can only occur when the flour contains an active ferment which keeps changing the starch into sugar. That this view is generally accepted in practice is shown by the fact that, when using flours deficient in such ferment, bakers commonly add to the flour, yeast, salt, and water, a quantity of malt extract, the characteristic constituent of which is the sugar producing ferment of the malt. This use of malt extract is now extending to the millers, several of whom have installed in their mills plant for spraying into their flour a strong solution of malt extract. It seems to be agreed by millers and bakers generally that such an addition to a flour which makes small loaves distinctly increases the size of the loaf. There can be no doubt that this effect is produced by the ferment of the malt extract keeping up the supply of sugar, and thus enabling the yeast to maintain the pressure of gas in the dough right up to the moment when it goes into the oven. The view that the shape of the loaf is due to the effect of salts, and particularly of phosphates, on the coherence of the gluten has also been put to practical use by the millers and the bakers. Preparations of phosphates under various fancy names are now on the market, and are bought by bakers for adding to the flour to strengthen the gluten and produce more shapely loaves. A few millers too are beginning to spray solutions of phosphates into their flours with the same object in view, and such additions are said to make material improvements in the shape of the loaf produced by certain weak flours.