SPAVIN. 
305 
the disease of spavin might have its beginning within the capsular 
ligament of the hock joint. That in all cases of inveterate and in- 
curable spavin the synovial membrane is the seat— the main seat 
— of disease, and that this is the principal reason why all our 
known means of cure fail, is a fact beyond all doubt or dispute : at 
the same time, the supposition that the disease, although attended 
by lameness in its early stages, may and frequently does consist in 
pure exostosis, will account for the fact of cases of spavin, when 
timely and effectively treated, occasionally admitting of recovery. 
There is another fact to which I would call attention, from the 
circumstance of its appearing in corroboration of the disease of 
spavin having its commencement outside the joint, and making its 
progress into the inside. If we examine the cuneiform bones of a 
spavined hock after maceration, we shall perceive that the caries 
which their surfaces exhibit has evidently commenced upon their 
inner parts — that it has, to appearance, spread from the exostosis 
outside upon the articulating surfaces inside the joint; it very com- 
monly happening that the outer parts of the same surfaces remain in 
a sound state. Again, I have at the present moment another prepara- 
tion of the bones of the hock before me in which the two cushion 
bones are inseparably united along their front sides by ossification ; 
and yet so smooth are their exterior surfaces, that no spavin, or the 
slightest vestige of one, would be discoverable in the living subject. 
Such is a true case of occult , concealed , or indiscoverable spavin. 
Although the diseases inside and outside the joints are different 
at their commencement, one consisting in inflammation and ulcera- 
tion of a delicate membranous tissue — the synovial membrane — 
while the other consists in inflammation followed by ossification of 
fibrous or fibro-cartilaginous substance, yet in the end do both 
diseases merge into one and the same morbid action of ossification, 
tending in its progress to the cementing and fixing of parts, once 
moveable upon one another, together, and in the end converting 
the entire mechanism of the joint into one solidified diseased struc- 
ture, coated inside and out with porous rocky osseous deposit. 
And not onty does the hock itself suffer, until every joint consti- 
tuting it has become carious and ossified — the articulation between 
the tibia and astragalus being the last to contract the disease, 
hence the reason, as I said before, of spavined horses being able, 
lame as they may be, to work on — -but parts in the immediate 
vicinity likewise catch similar disease, among which the ligaments 
at the back of the hock joint, and the suspensory ligament at its 
place of origin, are the most commonly so affected. 
Various pathological causes for the lameness in spa- 
vin, it is evident, therefore, admit of demonstration. It was formerly 
