CHEMICAL SCIENCE. 243 



constituents of the grain, is to be attributed solely to the mode of preparing 

 the flour, and the process followed for making that flour into porous bread. 



The great object sought after, both by the miller and the baker, is the pro- 

 duction of a white and light loaf. Experience has taught the miller that the 

 flour which makes the whitest loaf is obtained from the centre of the grain; 

 but that the flour which is the most economical, and contains the largest 

 portion of sound gluten, is that which is obtained from the external portion 

 of the grain. But while he endeavors to secure both these portions for his 

 flour, he takes the greatest care to avoid, as much as possible, by fine dress- 

 ing, etc., the mixture with them of any part of the true external coat which 

 forms the bran, knowing that it will cause a most serious deficiency in the 

 color of the bread after fermentation. 



It is generally supposed that the dark color of brown bread that is, of 

 bread made from the whole wheaten meal is attributable to the colored 

 particles of the husk or outer covering of the grain. But such is not really 

 the case. The colored particles of the bran are of themselves only capable 

 of imparting a somewhat orange color to bread, which is shown to be the 

 fact when whole wheaten meal is made into bread by a process Yrliere no 

 fermentation or any chemical changes v/li^iever are allowed to take place. 

 Some few years since, a process was invented in America for removing the 

 outer seed coat of the wheat grain without injuring the grain itself, by 

 which it was proposed to save that highly nutritious portion which is torn 

 away, adhering to the bran in the ordinary process of grinding, and lost to 

 human consumption. The invention was brought under the notice of the 

 French Emperor, who caused some experiments to be made in one of the 

 government bakeries to test its value. The experiments were perfectly 

 satisfactory so far as the making of an extra quantity of white flour was 

 concerned; but when this flour was subjected to the ordinary process of 

 fermentation, and made into bread, much to the astonishment of the parties 

 conducting the experiments, and of the inventor himself, the bread was 

 brown instead of white. The consequence, of course, has been that the 

 invention has never been brought into practical operation. 



It has been estimated that as much as ten or twelve per cent of nutritious 

 matter is separated, adhering to the bran which is torn away in the process 

 of grinding; and until very lately this matter has been considered by chem- 

 ists to be gluten. It has, however, been shown by M. Mouries to be chiefly 

 a vegetable ferment, or metamorphic nitrogeneous body, which he has named 

 Cerealin, and another body, vegetable caseine. 



Cerealin is soluble in water, and insoluble in alcohol. It may be obtained 

 by washing bran, as procured from the miller, with cold water, in which it 

 dissolves, and it may be precipitated from the aqueous solution by means of 

 alcohol ; but, like pepsin, when thus precipitated it loses its activity as a 

 solvent or ferment. In its native state, or in aqueous solution, it acts as the 

 most energetic ferment on starch, dextrine, and glucose, producing the lactic 

 and even the butyric changes, but not the alcoholic. It acts remarkably on 

 gluten, especially when in presence of starch, dextrine, or glucose. The 

 gluten is slightly decomposed at first, giving ammonia, a brown matter, and 

 another production which causes the lactic acid change to take place in the 

 starch and glucose. The lactic acid thus produced immediately combines its 

 activity with that of the cerealin, and the gluten is rapidly reduced to solution. 

 The activity of the cerealin is destroyed at a temperature of one hundred 

 and forty degrees Fahrenheit, according to M. Mouries; but my OAvn experi- 



