BA FISTULA AND POLL-EVIL 
sore. The local dry gangrene called sitfast at 
the level of the collar seat is one of the com- 
monest causes as well as the initial lesion of the 
very gravest of fistule of this kind. Here the 
thick, folded, hair-clothed skin and also the 
thick pad of connective tissue underlying the 
mane first undergo gangrene from collar pres- 
sure. Some of these sitfasts involve only the 
skin (superficial sitfast), others invade into 
the connective tissue and still others entirely 
through it, exposing the ligamentum nuche 
beneath. From this exposure the process 
marches on along the course of the ligament 
and there sows the seed of a chronic state pre- 
cisely the same as fistula from other causes, 
and requiring the same remedial measures. In 
fact, it is our experience that fistule of this 
origin are the most stubborn of all. 
Once seated in the ligament and_ bones, 
atypical fistula is identical with the one having 
its origin in a pre-existing cyst (typical fistula ) 
and will henceforth undergo the same course of 
successive abscess and tract formation. Ab- 
scesses form, burrow to the surface, discharge 
for a time, heal up, gather again and burst at 
another point, and this chain of events may re- 
cur indefinitely. During the formation of a 
new abscess there is local pain, distressed move- 
ments, fever and a general indisposition just 
