THE DESTRUCTION OF WOOD BY FUNGI 363 



animal has been the cause of the breaking of certain dams in 

 Holland, 1 with the loss of many human lives. 



It is well known that many insects bore into wood. Accord- 

 ing to Drummond, 2 in certain parts of tropical Africa not a stick 

 falls to the ground but is immediately converted into powder by 

 the activity of the Termites or White Ants. The true Ants, too> 

 sometimes make their living-rooms in wood. 



Numerous species of Coleoptera inhabit wood. One of the 

 best known is Anobium striatum, which often destroys furniture, 

 in which it bores circular holes. This insect flourishes in air- 



* 



dry timber, where it is practically free from all competitors. No 

 fungus could grow under such conditions. It seems probable that 

 Anobium and its allies obtain the water necessary for the 

 structure of their tissues by splitting up carbohydrates such as 

 cellulose and starch. The beetles live upon the wood into 

 which they bore. The exact manner in which they act upon the 

 lignified membranes still requires elucidation, but doubtless they 

 digest the starch and protoplasm contained in the medullary 

 rays and wood parenchyma by acting upon them with appropriate 

 enzymes. 



We may now consider the vegetable organisms which destroy 

 wood. Bacteria are the cause of the breaking down of so many 

 organic substances that it might well be expected that they are 

 also concerned in the destruction of wood. As yet, however, no 

 wood-destroying bacteria have been isolated. Bacteria which 

 destroy unlignified membranes, consisting of cellulose, are very 

 wide-spread in nature, and, as Omelianski 3 has shown, can be 

 obtained from any soil containing humus, or pond where vege- 

 table matter is decomposing. Nevertheless, when cellulose 

 cell-walls have become lignified, they long resist the action of 

 bacteria. These organisms are unable to penetrate into solid 

 wood, and thus have little chance to act upon it until, owing to 

 the attacks of fungi, it has reached the last stages of destruction. 



The chief agency at work in destroying wood is undoubtedly 

 the Fungi. Of these the groups concerned are the Ascomycetes 

 and the Basidiomycetes. 



In order to clear the way for subsequent remarks, it may be 



1 R. Hertwig, loc. cit. p. 328 ; vide also Hedley, Austral. Ass. Adv. Sci. 1901, 



P- 237- 



2 H. Drummond, Tropical Africa. 



3 Omelianski, Ref. in Chem. Centralbl. 1898, Bd. I. p. 269. 



