374 DISEASES OF THE HORSE. 
pelled to perform when too young. It may also be due to other 
diseases existing in parts below the knee joint. 
Symptoms.—This change of direction largely influences the move- 
ment of the animal by detracting from its firmness and practically 
weakening the entire frame, even to the extent of rendering him in- 
secure on his feet and liable to fall. This condition of weakness is 
sometimes so pronounced that he is exposed to fall even when stand- 
ing at rest and unmolested, the knees being unable even to bear their 
portion of the mere weight of the frame. This results in another 
trouble—that of being unable to keep permanently upright. He is 
liable to fall on his knees, and by this act becomes presently a sufferer 
from the lesion known by the term of “broken knees.” 
Treatment-—W hatever may be the originating cause of this imper- 
fection, it detracts very largely from the usefulness and value of a 
horse, disqualifying him for ordinary labor and wholly unfitting him 
for service under the saddle without jeopardizing the safety of his 
rider. If, however, the trouble is known from the start, and is not 
the result of congenital deformity or weakness of the knee joint, or 
secondary to other diseases, rest, with fortifying frictions, may some- 
times aid in strengthening the joints; and the application of blisters 
on the posterior part of the knee, from a short distance above to a 
point a little below the joint, may be followed by some satisfactory 
results; but with this trouble, as with knuckling fetlocks, the danger 
of relapse must be kept in mind as a contingency always liable to 
occur. 
CURB. 
This lesion is the bulging backward of the posterior part of the 
hock, where in the normal state there should be a straight line, extend- 
ing from the upper end of the point of the hock down to the fetlock. 
Cause.—The cause may be a sprain of the tendon which passes on 
the posterior part of the hock, or of one of its sheaths, or of the 
strong ligament situated on the posterior border of the os calcis. 
Hocks of a certain conformation seems to possess a greater liability 
to curb than others. They are overbent, coarse, and thick in appear- 
ance, or may be too narrow from front to back across the lower por- 
tion. This condition may therefore result as a sequence to congeni- 
tal malformation, ‘as in the case of horses that are “saber-legged.” 
It often occurs, also, as the result of violent efforts, of heavy pulling, 
of high jumping, or of slipping; in a word, it may result from any of 
the causes heretofore considered as instrumental in producing lacera- 
tions of muscular, tendinous, or ligamentous structure. 
Symptoms.—A hock affected with curb will present at the outset 
a swelling more or less diffuse on its posterior portion, with varying 
degrees of heat and soreness, and these will be accompanied with 
