TANNIN. 157 



the most easily when made into dough ; it is for this rea- 

 son that the Italian pastes are made of the flour of the 

 hard wheat from the Crimea, instead of that from the 

 wheat of the north. 



Amongst all the different kinds of bread corn, those 

 from the flour of which the best bread is made, and of 

 which the dough rises or ferments the most readily, are 

 those which contain the most gluten : they may be ranked 

 in the following order. 



1. Wheat, containing from y^^^ to -^jP^- of its weight of 

 gluten. 



2. Barley, from y^^ to yf^ 



3. Rye, from ^^ to y^^ 



4. Oats, from ^ to y§^ 



When grain or flour has undergone any change by which 

 the gluten is destroyed, the bread made from it is bad and 

 unwholesome, and such grain or flour should only be em- 

 ployed for making starch. 



Flour which contains but little gluten, or which has been 

 deprived of it, if made into bread, turns sour by fermenta- 

 tion ; the dough does not rise, and when baked is acid, 

 heavy, and indigestible. 



There are some very nutritive vegetables in which the 

 starch, instead of being combined with gluten, as it is in 

 the bread corns, is united with mucilage ; this is the case 

 in peas, beans, and potatoes. The flour of these will not 

 alone make bread ; but it is frequently used in years of 

 scarcity, mixed with that of wheat, to increase the quantity 

 of bread. Dough made of flour thus mixed does not fer- 

 ment so completely, as that made entirely from wheat 

 flour ; the bread, however, is well tasted and wholesome, 

 and preserves its freshness for even a longer time than the 

 other. 



ARTICLE IX. 



Tannin. 



Tannin, or the astringent principle, is contained in 

 a great variety of vegetables ; it is of a brown color, high- 

 ly astringent, and dissolves readily both in water and alco- 

 14 



