INFLAMMATORY AFFECTIONS 285 
and is more or less granular and inclined to break up under 
manipulation. As a consequence, any rough use of the 
drawing-knife, or an accidental wounding with sharp flints 
or stones, leads to exposure of the sensitive structures and 
local gangrene. 
With the horn of the sole thus deteriorated by reason of 
excessive and continued pressure upon the. parts secreting 
it, it is not surprising to find that, in many cases, actual 
penetration of it with the os pedis occurs. It is the anterior 
portion of the inferior margin of the bone that makes its 
Fig. 123.—Sonar Aspect oF Foor wit Curonic LamMINITIs, SHOW- 
ING Its ABNORMAL OvaL SHAPE FROM BEFORE BacKWARDS, AND 
THE Excess of HorN GROWING FROM THE WHITE LINE IN THE 
ReGIon oF THE TOE. 
appearance, and shows itself as a small semicircular white 
or dark gray line on the sole. 
Exposure of the bone is soon followed by its necrosis, in 
which case the wound takes on an ulcerating character. 
From it there is ~ discharge of pus, black in colour and 
offensive in smell, and, protruding from the opening, are 
excessive granulations of the remains of the sensitive sole. 
The ‘white line,’ so apparent when a normal foot is 
cleaned with the knife, can no longer be sharply distin- 
guished from the surrounding horn, while in some cases the 
