AZOTIZED PRINCIPLES. 77 



elastic substance of a peculiar heavy odor ; this is the gluten of 

 chemists. By this simple process of analysis, however, we are en- 

 abled in many cases to estimate the quality of a sample of flour with 

 reference to its richness in gluten, a substance which is rightly 

 considered as the most essential among the nutritive elements of the 

 cereals. 



The washings collected and allowed to stand, soon become clear : 

 the starch which was suspended in the liquid subsides, accompanied 

 by flakes of an animalized matter. If the clear liquor be decanted 

 and boiled, a white froth appears upon its surface, which, skimmed 

 off", is found to have the appearance of coagulated white of egg, and 

 which, in fact, has all the characters of animal albumen. The water 

 from which the albumen is solidified, necessarily contaius all the 

 soluble substances of the flour. On evaporation, it leaves substances 

 similar to gum and sugar, and traces of saline matters. 



With the exception of the starch, which contains very little for- 

 eign matter, the different substances obtained by this process of 

 washing are far from being in a state of purity. I have said that all 

 seeds contain fatty substances, but in the products of the operation 

 just described, no oily matter was detected. As it cannot be discov- 

 ered in perceptible quantity in starch, nor in the substances soluble 

 in water, it must remain attached to the gluten ; and this is actually 

 the case. The gluten, the coagulated albumen then, are not pure 

 proximate principles ; fat or oil may be obtained from them ; and 

 further, by examining common gluten carefully, we learn that it con- 

 tains several azotized substances, which differ from one another. By 

 boiling crude gluten with alcohol we ultimately obtain a fibrous gray- 

 ish residue, called by M. Dumas vegetable fibrine. On cooling, the 

 alcoholic liquor lets fall a substance which in its properties resembles 

 the caseum or curd of milk. Lastly, if the cold alcoholic solution 

 be concentrated, a pultaceous substance separates from it, called by 

 Messrs. Dumas and Cahours glutine. 



Analysis, accordingly, indicates the presence of four azotized sub- 

 stances in wheat ; and when these are all combined in the mass of 

 gluten obtained by washing a lump of dough, they retain fatty mat- 

 ters, from which they may be freed by means of alcohol and ether. 

 The following, according to MM. Dumas and Cahours, is the com- 

 position of the azotized principles of wheat, dried at 140 centig. 

 (284° F.)* 



Carbon. Hydroofen. Azote. Oxva-en, bulph. and 



' Pho.<piiurus. 



Fibrine 53.2 7.0 16.4 23.4 



Albumen 53.7 7.1 15.7 20.5 



Caseine (caseum) 53-5 7.1 16.0 23.4 



Glutine 53.3 7.2 15.9 23.8 



Legumine. Some vegetables, particularly some seeds, contain a 

 substance different from any of those just described. This M. Bra 

 connot was the first to notice in the seeds of the family of the Le 

 guminosae, and it has been since detected by Dumas and Cahours in 



* Dumas et Cahours, Annates de Chimie et Je Physique, p. 390, 3e s6rie. 



7* 



