THE CHEMISTRY OF COOKERY. 515 



grains until reduced to small pills of gluten, and then swallowing 

 these. Mild indigestion or acute spasms will follow, according to the 

 quantity taken and the digestive energies of the experimenter. Raw 

 flour will act similarly but less decidedly. 



Bread-making is the most important, as well as a typical example, 

 of the cookery of grain-food. The grinding of the grain is the first 

 process of such cookery ; it vastly increases the area exposed to the 

 subsequent actions. 



The next stage is that of surrounding each grain of the flour with 

 a thin film of water. This is done in making the dough by careful 

 admixture of a modicum of water and kneading in order to squeeze 

 the water well between all the particles. The effect of insufficient en- 

 veloping in water is sometimes seen in a loaf containing a white pow- 

 dery kernel of unmixed flour. 



If nothing more than this were done, and such simple dough wei'e 

 baked, the starch-granules would be duly broken up and hydrated, the 

 gluten also hydrated, but, at the same time, the particles of flour 

 would be so cemented together as to form a mass so hard and tough 

 when baked that no ordinary human teeth could crush it. Among all 

 our modern triumphs of applied science none can be named that is 

 more refined and elegant than the old device by which this difficulty 

 is overcome in the every-day business of making bread. Who invent- 

 ed it, and when, I do not know, but perhaps Mr. Clodd can tell us. 

 Its discovery was certainly very far anterior to any knowledge of the 

 chemical principles involved in its application. 



The problem has a very difficult aspect. Here are millions of par- 

 ticles, each of which has to be moistened on its surface, but each when 

 thus moistened becomes remarkably adhesive, and therefore sticks fast 

 to all its surrounding neighbors. We require, without suppressing 

 this adhesiveness, to interpose a barrier that shall sunder these mill- 

 ions of particles from each other so delicately as neither to separate 

 them completely, nor allow them to completely adhere. 



It is evident that if the operation that supplies each particle with 

 its film of moisture can simultaneously supply it with a partial atmos- 

 phere of gaseous matter, the difficult and delicate problem will be ef- 

 fectively solved. It is thus solved in making bread. 



As already explained, the seed which is broken up into flour con- 

 tains diastase as well as starch, and this diastase, when aided by moist- 

 ure and moderate warmth, converts the starch into dextrine and sugar. 

 This action commences when the dough is made, and this alone would 

 only increase the adhesiveness of the mass, if it went no further ; but 

 the sugar thus produced may, by the aid of a suitable ferment, be con- 

 verted into alcohol. As the composition of alcohol corresponds to that 

 of sugar, minus carbonic acid, the evolution of carbonic-acid gas is an 

 essential part of this conversion. 



With these facts before us, their practical application in bread- 



