i62 TIMBER AND SOME OF ITS DISEASES, [chap. 



of the pines, &c.) into the resin passages. The hyph^ 

 of the ultimate twigs enter the tracheides, vessels, &c., 

 of the wood, and delignify them, with changes of 

 colour and substance as described. Reference must 

 be made to Prof Hartig's publications for the details 

 which serve to distinguish histologically between timber 

 attacked by Agaricus malleus and by Trametes or other 

 fungi. Enough has been said to show that diagnosis 

 is possible, and indeed, to an expert, not difficult. 



It is at least clear from the above sketch that we 

 can distinguish these two kinds of diseases of timber, 

 and it will be seen on reflection that this depends on 

 knowledge of the structure and functions of the 

 timber and cambium on the one hand, and proper 

 ^acquaintance with the biology of the fungi on the 

 other. It is the victory of the fungus over the timber 

 in the struggle for existence which brings about the 

 disease ; and one who is ignorant of these points will 

 be apt to go astray in any reasoning which con- 

 cerns the whole question. Any one knowing the facts 

 and understanding their bearings, on the contrary, 

 possesses the key to a reasonable treatment of the 

 timber; and this is important, because the two 

 diseases referred to can be eradicated from young 

 plantations, and the areas of their ravages limited in 

 older forests. 



