60 FISTULA AND POLL-EVIL 
swellings that are not easy to differentiate from 
the saccular and phlegmonous conditions as- 
sociated with the graver state preceding the 
fistulous stage. Subcutaneous and subfascial 
sanguinous sacs and hemotomata complicated 
or uncomplicated with infection, are the mos? 
misleading of these lesions for which fistulee 
might be mistaken. The differentiation can 
never be made with certainty until the behavior 
of the swelling is noted, both before and after 
evacuating the contents. In fistula such swell- 
ings accentuate; in the others they subside, 
either with or without lancing. Besides they 
are always diffuse whereas the fistule presents 
a spherical swelling in almost every instance. 
Although acute diseases running | short 
courses, malignant edema and other erysip- 
elatous inflammations when attacking the 
withers may at first mislead the diagnostician, 
these are recognized by their acuteness and 
rapid advancement into adjacent regions and 
the serious concomitant toxemia. 
The early symptoms of the atypical form are 
likewise very often misleading. That any given 
harness sore will or will not end favorably is 
not always easy to determine. What might at 
first seem like a simple enough harness sore 
may finally prove to be the initial phase of a 
bad fistula. On the other hand, a badly in- 
