NINTH ANNUAL YEAR BOOK— PART X 425 
Causes. — Fistulas follow as a result of abscesses, bruises, wonuds, or 
long-continued irritation by the harness. Among the more common 
causes of fistula of the poll (poll evil) are chafing by the halter or heavy 
bridle; blows from the butt end of the whip; the horse striking his head 
against the hayrack, beams of the ceiling, low doors, etc. Fistulous 
withers are seen mostly in those horses that have thick necks as well 
as those that are very high in the withers, or, among saddle horses, 
those that are very low on the withers, the saddle here riding forward 
and bruising the parts. They are often caused by bad-fitting collars or 
saddles, by direct injuries from blows, and from the horse rolling upon 
rough or sharp stones. In either of these locations ulcers of the skin, or 
simple abscesses, if not properly and punctually treated, may become 
fistulas. The pus burrows and finds lodgment deep down between the 
muscles, and escapes only when the sinus becomes surcharged or when, 
during motion of the parts, the matter is forced to the surface. 
Symptoms. — These, of course, will vary according to the progress made 
by the fistula. Following an injury we may often notice soreness or stiff- 
ness of the front legs, and upon careful examination of the withers we 
will see small tortous lines running from the point of irritation down- 
ward and backward over the region of the shoulder. These are superfi- 
cial lymphatics, and are swollen and painful to the touch. In a day or 
two a swelling is noticed on one or both sides of the dorsal vertebraw, 
which is hot and painful and rapidly enlarging. The stiffness of the 
limbs may disappear at the time, and the heat and soreness of the parts 
may become less noticeable, but the swelling remains and continues to 
enlarge. 
A fistulous ulcer of the poll may be first indicated by the opposition 
which the animal offers to the application of stable brush or bridle. At 
this time the parts are so sore and sensitive that there is some danger 
that the patient will acquire disagreeable stable habits unless handled 
with the greatest care. The disease in its early stages may be recognizd 
as a soft, fluctuating tumor surrounded by inflammatory swelling, with 
the presence of enlarged lymphatic vessels and stiffness of the neck. 
Later the inflammation of the surrounding tissues may disappear, leav- 
ing a prominent tumor. The swelling, whether situated upon the head 
or the withers, may open and form a running ulcer, or its contents may 
dry up and leave a tumor which gradually develops the common char- 
acteristics of a fibrous tumor. When the enlargment has opened we 
should carefully examine its cavity, as. upon its condition will wholly de- 
pend our treatment. 
Treatment. — In the earliest stage, when there is soreness, enlarged 
lymphatics, but no well marked swelling, the trouble may frequently be 
aborted. To do this requires both general and local treatment. A 
physic should be given, and the horse receive 1 ounce of powdered salt- 
peter three times a day in his water or feed. If the fever runs high, 
20-drop doses of tincture of aconite root every two hours may be admin- 
istered. The local application of cold water to the inflamed spot for an 
hour at a time three or four times a day has often proved very beneficial, 
and has afforded great relief to the patient. 
