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! 
42 Williams, Fisher, and Udall: The Spavin Group. 
, the designation is wholly inappropriate, and that as a rule there 
is increased synovial accumulation. 
Exostosis constitutes perhaps the most constant change. It 
‘ occurs early in the disease and may be of every conceivable 
degrge, from minute elevations of bone, undistinguishable dur- 
ing life, to enormous enlargements sometimes developing chiefly 
on one side of the joint, tending to throw the bones out of their 
normal direction, causing great deformity. The exostoses are 
nearly always symmetrical, which may lead to confusion, two 
spavins of equal size being frequently regarded as ‘“‘ rough” 
hocks. ‘ 
Heat is rarely recognized as a symptom, but may be present 
in very active disease of such a joint as the hock or stifle. 
Pain is chiefly expressed as a resuit of locomotion or the 
bearing of the animal’s weight upon the affected part. It can- 
not generally be induced by ordinary digital compression or 
manipulation. In navicular disease, pain is evinced sometimes 
by striking the sole or frog with a hammer, by pressing over 
the bursa with hoof testers, and by compressing the bursa from 
the heel with the thumb. Compression of the navicular bone 
by causing the animal to bear its weight on a wedge, with its 
base directed forward also causes an expression of pain. 
In spavin, the flexing of the hock (spavin test) by* compress- 
ing the small bones of the tarsus causes pain which finds expres- 
sion in increased limping when the foot is released. 
The constitutional symptoms are of every grade. In a large 
proportion of cases they are absent or too inconspicuous to at- 
tract attention. In severe cases there are general symptoms of 
ill health, in numerous cases the patient is listless, very disinclined 
to move, there are digestive derangements, with marked loss of 
flesh. 
As already related under pathology, the urine appears to 
contain an excess of phosphates. This symptom has not yet 
been sufficiently studied to make it reliable and available, but we 
have strong hopes that in the near future urinalysis may become 
a valuable guide in diagnosing the malady.’ 
DIFFERENTIAL DIAGNOSIS. 
We need to differentiate this group of affections from other 
maladies and also to distinguish between the individual members 
of the group. 
