Vii.] THE "DRY-ROT" OF TIMBER. 195 



Merulius lacrymans : the structure, &c., of the 

 fructification are also different. I have shown in Fig. 

 24 a piece of wood undergoing destruction from the 

 action of the mycelium of this Polyporus, and it will 

 be seen how the diseased timber cracks just as under 

 the influence of Merulius. 



Now Polyporusvapomrius is common in the forests, 

 and it has been found that its spores may lodge in 

 cracks in the barked logs of timber lying on the 

 ground cracks such as those in Fig. I, p. 3). In 

 the particular forests of which the following story 

 is told, the felling is accomplished in May (because 

 the trunks can then be readily barked, and also 

 because such work cannot be carried on there in the 

 winter), and the logs remain exposed to the sun and 

 rain, and vicissitudes of weather generally, for some 

 time. Now it is easy to see that rain may easily wash 

 spores into such cracks as those referred to, and 

 the fungus obtains its hold of the timber in this 

 way. 



The next stage is sending the timber down to the 

 timber-yards, and this is accomplished, in the districts 

 referred to, by floating the logs down the river. Once 

 in the river, the wood swells, and the cracks close up ; 

 but the fungus spores are already deeply imprisoned 

 in the cracks, and have no doubt by this time 



O 2 



