se that ran away up a steep hill.
After going a few hundred yards the animal abated its speed, when the
rider raised his hand to strike. Catching sight of the whip, the horse
sprang forward, while the man felt an acute pain and a sense of
something having given way at his shoulder. He did not fall off, but
rode a little further and was helped to dismount. On examination a
subcoracoid dislocation of the head of the humerus was found. The
explanation is that as the weight of the whip was inconsiderable (four
ounces) the inertia of the arm converted it into a lever of the first
order. Instead of fulfilling its normal function of preventing
displacement, the coraco-acromial arch acted as a fulcrum. The limb
from the fingers to that point acted as the "long arm," and the head
and part of the neck of the humerus served as the "short arm." The
inertia of the arm, left behind as it were, supplied the power, while
the ruptured capsular ligament and displacement of the head of the bone
would represent the work done.

Congenital Dislocations.--The extent and accuracy of the knowledge
possessed by Hippocrates on the subject of congenital dislocations have
excited the admiration of modern writers, and until a comparatively
recent time examples of certain of the luxations described by him had
not been recorded. With regard, for instance, to congenital
dislocations at the shoulder-joint, little or nothing was known save
what was contained in the writings of Hippocrates, till R. M. Smith and
Guerin discussed the lesion in their works.

Among congenital dislocations, those of the hips are most common--in
fact, 90 per cent of all. They are sometimes not recognizable until
after the lapse of months and sometimes for years, but their
causes--faulty developments of the joint, paralysis, etc.--are supposed
to have existed at birth. One or both joints may be involved, and
according to the amount of involvement the gait is peculiar. As to the
reduction of such a dislocation, the most that can be done is to
diminish the deformity and functional disability by traction and
palliative measures with apparatus. The normal structure of the joint
does not exist, and therefore the dislocation admits of no reduction.
Congenital dislocations of the shoulder are also seen, owing to faulty
development of the glenoid fossa; and at the knee, the leg generally
being in extreme hyperextension, the foot sometimes resting on the
abdomen. Congenital luxation of