318 DISEASES OF THE HOESE. 



the importance of its action to the perfect fulfiUment 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 teimination, 

 is usually the effect of a traujnatic 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. — ^The 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 postm^e 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 tlie 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. 



