VII.] 



THE "DRY-ROT" OF TIMBER. 



197 



depths of the cracks are first diseased, and the 

 mycelium spreads thence. 



Obviously some protection would be afforded if the 

 bark could be retained on the felled logs, or if they 

 could be at once covered and kept covered after bark- 



FIG. 25. Part of a longitudinal radial section through a piece of wood infected with 

 Poiyporus igniarius. After Hartig (highly magnified). 



ing ; and, again, something towards protection might 

 be done by carting instead of floating the timber, when 

 possible. At the same time, this is not a reliable 

 mode of avoiding the disease by itself ; and even the 

 dry top logs in the saw-yard are not safe. Suppose 

 the following case. The top logs of the stack are 



