3Q6' COMPOUND PRODUCTS. CHAP. I. 



SECTION IV. 



Gluten. 



How pro- GLUTEN is that part of the paste formed from 

 the flour of wheat, that remains unaffected by the 

 water after all the starch contained in it has been 



Proper- ' washed off. It is a tough and elastic substance, of 



ttpe 



a dull white colour, without taste, but of a very 

 peculiar smell. It is soluble in the acids and al- 

 kalies, but insoluble in water and in alcohol. 



When exposed to the action of the air it gra- 

 dually dries and hardens, and assumes a dark 

 brown colour with a slight degree of transparency, 

 resembling glue, except that it is brittle, and breaks 

 like glass. When kept for some time in a place 

 that is moist it undergoes a species of fermentation, 

 in which it swells and emits air bubbles consisting 

 of hydrogene and carbonic acid gas. When ex- 

 posed in a dry state to heat it cracks, swells, and 

 melts, and exhales a fetid odour, burning like horn 

 or feathers. When distilled it yields ammonia, 

 and an empyreumatic oil, and leaves a charcoal 

 that is with difficulty reduced to ashes. 



The above properties of vegetable gluten indicate 

 its relation to animal gluten, particularly the phe- 

 nomena of its fermentation and destructive distill- 

 ation, by which it is found to contain, as one of its 

 constituent principles, a portion of nitrogene. 



