EXPERIMENTAL. 107 



the same proportion of dry gluten, viz, 34.6 per cent. The yield of dry- 

 gluten was accordingly in the first case 15.41 grams and in the second 9.56 

 grams. The difference, 5.85 grams, shows that the added gliadin was fully 

 recovered in the gluten. 



The figures show that these proteins combine with about twice their 

 weight of water in forming gluten. The fact that the added gliadin entered 

 so readily and completely into the formation of gluten indicates that it 

 exists in the seed as such and undergoes no chemical change during extrac- 

 tion and drying. 



The properties observed in testing the separated gliadin show how it acts 

 in forming gluten and explain many of the points observed by others and 

 attributed to a ferment-action. 



When treated with distilled water in small amount, the fine-ground air-dry 

 gliadin at once forms a sticky mass, which, on adding more distilled water, 

 dissolves to a turbid solution. If, however, a very little sodium chloride is 

 added to distilled water and this applied to gliadin that has been first 

 moistened with pure water, a very coherent, viscid mass results, which 

 adheres to everything it touches and can be drawn out into long threads. 

 If the gliadin is moistened with 10 per cent sodium-chloride solution and then 

 treated with a larger quantity of this solution, the substance unites to a 

 plastic mass, which can be drawn out into sheets and strings, but is not 

 adhesive. From this it is evident why Ritthausen, in washing flours which 

 gave a fluid gluten, obtainable only in small quantity and with great diffi- 

 culty, found that the addition of calcium sulphate to the wash-water ren- 

 dered the gluten much more coherent and easily obtainable. The gliadin is 

 thus proved to be the binding material which causes the particles of flour to 

 adhere to one another, thus forming a dough. But the gliadin alone is not 

 sufficient to form gluten, for it yields a soft and fluid mass, which breaks up 

 entirely on washing with water. The insoluble glutenin is probably essen- 

 tial by affording a nucleus to which the gliadin adheres and from which it 

 is not mechanically carried away by the wash-water. 



The behavior of the gliadin toward 10 per cent sodium-chloride solution 

 shows why no gluten was obtained by Weyl & Bischoff from flour extracted 

 with this solvent. The gliadin had under these conditions no adhesive quali- 

 ties, and therefore was unable to bind the flour into a coherent mass. If, 

 however, the salt solution is added in small quantities and the flour kneaded 

 and pressed, the particles are brought together and then adhere tenaciously. 



