80 



composition necessarily succeeds : the constituent parts separate, 

 and the elementary, or simple principles, disengaged from those 

 connections into which they had been forced by the energies of ve- 

 getable life, now enter into new combinations, resulting, almost, 

 from chemical attractions merely. 



The epidermis, as well as the parenchyma of the leaves, and the 

 other succulent parts, soon become resolved into a soft mass, which 

 yields an unpleasant odour, and which acquires much of its moisture 

 from the extravasation of the sap and other vegetable juices. The 

 mass derives, perhaps also an increase of its fluidity, from the hydro- 

 gen and oxygen, which had been employed in the. formation of vari- 

 ous parts of the vegetable, being now let loose, and entering into a 

 new combination, by which water is formed. Another portion of the 

 hydrogen becomes also volatilized, and uniting with a portion of car- 

 bon, forms carburetted hydrogen gas, and other inflammable gases, 

 somewhat similar in their composition. In the decomposition of 

 those plants, into the composition of which nitrogen enters, this 

 principle enters directly into union with the hydrogen, at the mo- 

 ment of their liberation, forming the volatile alkali ; the odour of 

 which is sometimes perceptible. The carbon, or coaly matter, is 

 partly employed, though but to a small extent, in the combinations, 

 with the hydrogen gas, just mentioned ; whilst another small por- 

 tion combines with the oxygen gas, and is liberated in the form of 

 carbonic acid gas. The oxygen is chiefly disposed of in the combi- 

 nations already described. Some of this principle, however, as well 

 as a portion of the hydrogen and of the nitrogen also, if present, as- 

 sumes the concrete state, and becomes involved with a very consi- 

 derable portion of the carbon, in the magma, from which the 

 gaseous and the more volatile parts have escaped. 



After this mass has been exposed to the atmosphere for some 

 time, and the evaporation of its more humid parts has taken place, 

 a small portion of soft, dark brown, or black, pulverulent matter is 



