ISO TIMBER AND SOME OF ITS DISEASES, [chap. 



in a plantation, &c., are : the leaves turn pale, and 

 then yellow, and die off; then the lower part of the 

 stem begins to die, and rots, though the bark higher 

 up may preserve its normal appearance. If the bark 

 is removed from one of the diseased roots or stems, 

 there may be seen the flat, silky, white bands of 

 mycelium running in the plane of the cambium, and 

 here and there protruding tiny white cushions between 

 the scales of the bark (Fig. 12) ; in advanced stages 

 the fructifications developed from these cushions may 

 also be found. The wood inside the diseased root will 

 be soft and damp, and in a more or less advanced 

 stage of decomposition. 



On examining the timber itself, we again obtain dis- 

 tinctive characters which enable the expert to detect 

 the disease at a glance. I had the good fortune some 

 time ago to spend several pleasant hours in the Miinich 

 Museum examining and comparing the various diseases 

 of timbers, and it is astonishing how well marked the 

 symptoms are. In the present case the wood at a 

 certain stage presents the appearance represented in 

 the drawing. Fig. 13. The general tone is yellow, 

 passing into a browner hue. Scattered here and there 

 in this ground-work of still sounder wood are peculiar 

 oval or irregular patches of snowy white, and in the 

 centre of each white thatch is a black speck. Nothing: 



