DISEASES OF THE HORSE. 171 
dition of the cartilaginous cushions which cover the 
uniting surfaces of each bone or of the ligaments that 
surround the joint and bind the bones together ; some- 
times both are involved. This inflammatory condition 
of the joint may be considered the exciting cause of 
spavin, and, if not speedily removed, spavin soon follows; 
the synovial fluid, commonly called-joint oil, is soon ab- 
sorbed, the cartilages of ‘the joint are turned to bone, 
which unite one with the other, forming one solid.mass, 
destroying the mobility of the parts involved, and con- 
stituting what is technically called anchylosis of the 
hock-joint. This union of the bones is not always gen- 
eral, there being in many cases but two, three, or four 
of the bones involved. When these changes are con- ; 
fined to the cartilages, there is no external enlargement ;' 
on the contrary, when the ligaments surrounding th 
joint are involved, we have in all cases external e 
Targement. When the hock receives an injury, the 
course of treatment usually pursued by horsemen is 
very pernicious. The application of a blister to an in- 
flamed surface must do injury by i increasing the inflam. 
mation they wish to abate, and in many cases actually 
producing a spavin where it otherwise would not exist. 
I do not deny that blisters are necessary and useful in 
such cases, if properly applied ; but the idea of rubbing 
blisters on an inflamed surface, to reduce it, is like throw- 
ing shavings on burning coals to extinguish them. The 
educated physician, in applying a blister, does it so as 
to draw the inflammation from the part affected to a 
part where it will do no injury ; otherwise, it had better 
not be applied at all. When the disease has advanced 
so far as to produce alteration of structure in the part, 
the application of blisters is proper, not for the pur ose 
of curing the disease, but. with a view of removing the 
a 
