470 
W. J. MARTIN. 
should be taken into consideration by the practitioner. The 
so-called u spavin test,” in which the lame limb is strongly 
flexed and immediately after the animal is made to trot briskly, 
is, in my opinion, nearly worthless for diagnostic purposes. I 
have seen this applied to horses that were perfectly sound, and 
yet they would move off quite stiffly for a short distance, and 
markedly so if aged. Atrophied muscles in the patellar and glu¬ 
teal regions are rarely due to true bone spavin, this condition 
beinemost often seen in cases affected with rheumatoid arthritis 
of the hock and with gonitis chronica of the patella. 
A horse suspected of spavin lameness should, if possible, be 
s een by the practitioner at rest in the stable ; it will there be 
observed that the animal will flex the suspected limb much 
more than its fellow. This is done in a peculiar manner ; the . 
point of the toe is carried outward, and the heel of the foot, 
owing to the action of the abductor and the adductor muscles 
of the limb, will be rested upon the upper part of the opposite 
hoof. At this time, if the animal is made to move quickly over 
in the stall on the sound limb, the movement will be accom¬ 
plished with a sort of hopping action, and the lameness is quite 
marked as a rule. The animal moves with much more facility 
when made to move towards the lame leg. 
When the animal is trotted to halter the lameness is marked 
by a spasmodic or convulsive contraction and flexion on the hock 
joint and a rising and falling of the hip of the lame side. The 
limb when first placed upon the ground will rest upon the toe; 
but as the exercise is increased the animal will gradually place 
more and more of the foot upon the ground, until he is able to 
place the entire weight upon the heels. During this movement 
the leg, when carried in extension, does not move through the 
full segment of its circle of extension and flexion as in a healthy 
joint. This conditional movement is most marked just prior 
to the appearance of the exostosis. 
Ocular Inspection and Palpation .—In order to better ob¬ 
serve the presence of an exostosis upon a suspected joint, have 
the animal placed upon a level footing and with both limbs as 
