36 THE LARCH CANKER 
When part of the cambium has been destroyed, the rest 
makes up for the loss by greater activity, and opposite 
a canker the wood is abnormally thick, and the whole 
stem may bulge in a curious fashion. The same may happen 
at the sides as well, so that when one looks the canker full 
in the face it appears to be set in an especially broadened 
part of the stem (figs. 13 and 14). 
All the cells in the neighbourhood of a canker form large 
quantities of resin, which permeates all the tissues. This 
gradually oozes out through the shrivelled cortex and 
phloem, and losing its more volatile constituents on exposure 
to the air, hardens into large whitish drops. Such large 
quantities are often formed that it runs down a stem in 
streams, covering the bark for several feet. 
