318 DISEASES OF THE HORSE. 
the importance of its action to the perfect fulfillment of the function 
of locomotion by the hind leg who can comprehend the gravity of the 
only prognosis which can be justified by the facts of the case—a 
prognosis which is essentially a sentence of serious import in respect 
to the future usefulness and value of the animal. For no disease, if 
we except those acute inflammatory attacks upon vital organs to 
which the patient succumbs at once, is more destructive to the useful- 
ness and value of a horse than a confirmed spavin. Serious in its 
inception, serious in its progress, it is an ailment which, when once 
established, becomes a fixed condition which there is no known 
means of dislodging. 
Cause.—The periostitis, of which it is nearly always a termination, 
is usually the effect of a traumatic cause operating upon the compli- 
cated structure of the hock, such as a sprain which has torn a liga- 
mentous insertion and lacerated some of its fibers, or a violent effort 
in jumping, galloping, or trotting, to which the victim has been 
compelled by the torture of whip and spur while in use as a gambling 
implement by a sporting owner, under the pretext of “ improving his 
breed”; the extra exertion of starting an inordinately heavy load, 
or an effort to recover his balance from a misstep, slipping upon an 
icy surface, or sliding with worn shoes upon a bad pavement, and 
other kindred causes. We can repeat here what we have before 
said concerning bones, in respect to heredity as a cause. From our 
own experience we know of equine families in which this condition 
has been transmitted from generation to generation, and animals 
otherwise of excellent conformation have been rendered valueless by 
the misfortune of a congenital spavin. 
Symptoms.—tThe evil is one of the most serious character for other 
reasons, among which may be specified the slowness of its develop- 
ment and the insidiousness of its growth. Certain indefinite phenom- 
ena and alarming changes and incidents furnish usually the only 
portents of approaching trouble. Among these signs may be men- 
tioned a peculiar posture assumed by the patient while at rest, and 
becoming at length so habitual that it can not fail to suggest the 
action of some hidden disorder. The posture is due to the action of 
the adductor muscles, the lower part of the leg being carried inward, 
and the heel of the shoe resting on the toe of the opposite foot. Then 
an unwillingness may be noticed in the animal to move from one side 
of the stall to the other. When driven he will travel, but stiffly, with 
a sort of sidelong gait between the shafts, and after finishing his 
task and resting again in his stall will pose with the toe pointing for- 
ward, the heel raised, and the hock flexed. Considerable heat and 
inflammation soon appear. The slight lameness which appears when 
backing out of the stall ceases to be noticeable after a short distance 
of travel. 
