170 PLANT LIFE 
the wood contains organic matter which is 
either soluble or easily rendered so, and this 
is one of the reasons why trees are felled at 
a time of the year in which the wood naturally 
contains least moisture or sap, and why the 
tree is, or should be, left to ‘‘ season ”’ (7. e. to 
dry) before being cut up. A source of danger 
to stored timber may arise from contamina- 
tion with organic matter consequent on the 
neglect of proper sanitary precautions. For 
wood which is so contaminated forms a very 
suitable substratum for the germination of 
a number of pests, and attacks of the 
dangerous “dry rot’”’ fungus (Merulius) has 
sometimes been traced to this source. When 
once a wood-destroying mycelium has estab- 
lished itself in a piece of timber it may be 
difficult to get rid of it. It will often lie 
dormant for a considerable time when the 
wood is dry, and only moisture or dampness 
is required to awaken it to dangerously active 
growth. 
The wood of living trees is liable to attack 
by various fungi which commonly gain access 
to it by means of wounds, due to abrasion of 
bark or the falling off of branches. The 
mischief is usually far advanced by the time 
the first symptoms are apparent, and it is 
often then too late to adopt remedial measures. 
In these matters “a stitch in time saves 
nine,” and it is generally a simpler matter 
to clean and tar a wound at once so as to 
prevent the entrance of the disease-producing 
