322 
W. L. WILLIAMS. 
Iii three of our cases the super-maxillary nerve seemed ab¬ 
normally large, while in the fourth it appeared smaller than 
usual—about one-third the size witnessed in the other cases. 
No histological investigations have been attempted. 
It occurs so far as observed by us in young or medium aged 
horses, of good breeding, well fed, very vigorous, high spirited 
and used lightly or moderately, usually for pleasure riding or 
driving. 
The disease comes on insidiously, and gradually increases 
in severity to its maximum, when it becomes fixed and perma¬ 
nent. The first symptoms noted, and which constitute the en¬ 
tire symptomatology except increase in severity and frequency, 
consist of a peculiar shaking of the head as though annoyed by 
flies about the ears or nostrils which the patient tries to dis¬ 
lodge, rubbing of the upper lip and nose against available ob¬ 
stacles, nervousness, halting at times as though the annoyance 
was too great to permit of progression. It is seen but little, if 
any, in the stall, but shows itself while the patient is being 
ridden or driven. In some, if not all cases, the symptoms are 
more severe when the animal is driven against the wind, in¬ 
creased velocity of the wind or speed of the animal tending 
usually to increase the annoyance. Some cases appear to be 
worse in cold, others in warm weather. 
The intensity and frequency of the jerking is variable in 
different patients and in the same animal at different times dur¬ 
ing the day or upon different days, but in a well established 
case the symptoms can in all cases observed by us be developed 
at will by riding or driving tl^e animal. The motions of the 
head are peculiar and diagnostic, the animal gives a sudden 
jerk of the head, the nose being quickly thrown forward and 
backward and if a convenient object be present the upper lip 
or nose is rubbed against it as if to dislodge an insect which 
was causing acute, stinging pain. 
If being driven double the upper lip may be rubbed against 
the pole, neck yoke or in a severe paroxysm the patient will 
halt in its gait and, turning its head toward its mate, rub its 
