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 
vegetable life, now enter into new combinations, resulting, almost 
merely, from chemical attractions. 
The epidermis, as well as the parenchyma of the leaves, and all 
the succulent parts, soon became 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 hy- 
drogen and oxygen, which had been employed in the formation of 
various 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 
carbon, 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 moment 
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 portion 
combines with the oxygen gas, and is liberated in the form of car- 
bonic acid gas. The oxygen is chiefly disposed of in the combinations 
already described. Some of this principle, however, as well as a 
portion of the hydrogen and of the nitrogen also, if present, assumes 
the concrete state, and becomes involved with a very considerable 
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 
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