THE FUNGI 169 
fragments of the carbohydrate are once more 
cast forth into the inorganic world as simple 
and vitally useless molecules. 
Let us take a specific instance by way of 
illustration of the foregoing consideration. 
Wood is an almost imperishable substance, at 
least under ordinary circumstances, and so 
long as it is preserved from the attacks of 
living organisms. But timber is liable to the 
depredations of a large number of different 
fungi which, under conditions favourable to 
their existence, are able to use it as food. 
They act on it by various ferments, bringing 
some of its constituents into solution, absorb- 
ing and partially breaking them down. The 
wood is soon reduced to a friable mass, 
weighing far less than the original timber, owing 
to the decomposition of its chemical substance, 
and the elimination of some of the products 
of its oxidation. Even the solid residue will 
soon disappear under the further influence 
of a succession of micro-organisms, which will 
finally disintegrate whatever the fungus may 
have left. Thus, in course of time, the whole 
of the chemical materials out of which the 
timber was constructed will again become 
part of the floating capital of nature, available 
for the constructive processes of new organ- 
isms, or destined for yet other purposes in the 
chemical change going on in the world. 
Most timbers are liable to infection by 
fungi when they are stored in a damp condi- 
tion. The danger is greatly accentuated if 
