390 ORGANIC CHEMISTRY. 



, r , 977. CHARACTERISTICS. If a bit of 



Mention a pe- 



culiarity of gluten be placed on the end of a wire and 

 burned, a very different odor is produced 



pounds. from that of burning starch or wood. 



The smell approaches that of burning wool, and is a 

 means of distinguishing organic matter which contains 

 nitrogen. If boiled with potassa, the sulphur of gluten 

 is extracted, and the solution will blacken paper moist- 

 ened with sugar of lead. This reaction furnishes an- 

 other means of detecting nitrogenous substances. 



978. PUTREFACTION. A still more im- 



Describethe . *.'. i_ 



process of pu- portant distinction of nitrogenous substan- 

 trefaction. ceg f rom those which contain no nitrogen, 

 is their spontaneous putrefaction. Left to themselves, 

 they are resolved, like blood and flesh to which they 

 are allied in composition, into a variety of other pro- 

 ducts. It is not strictly correct to say that this decom- 

 position is spontaneous. The substance must first 

 have been exposed to the air. An oxidation or slow 

 combustion is then commenced, which, although en- 

 tirely imperceptible in its effects, and checked at once 

 by exclusion of air, ensures the subsequent putrefac- 

 tion. It burns out a small portion of carbon and hy- 

 drogen, and thus removes, as it were, the key-stone of 

 the arch in every molecule. The atoms may then be 

 supposed to fall together and re-arrange themselves as 

 is required by the known products of their decompo- 

 sition. 



979. PRODUCTS OF PUTREFACTION. The 



Mention some ^. 'L- % > ' r 



products of re-arrangement which occurs m putrefac- 

 ef action. cons i stSj essentially, in the combustion 



