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 



