EDITORIAL. 
375 
the antero-internal part of the hock, means the long series of 
pathological lesions which veterinarians are more apt to under¬ 
stand under the general classification of hock diseases. And, 
yet, while most veterinarians realize the true condition of affairs 
and appreciate the fact of the many alterations that can be 
found under the general denomination of spavin, there remains 
some doubt as to the manner in which the lesions develop. 
The various opinions of pathologists can be divided into 
two groups : first, those that admit that the morbid process pro¬ 
gresses from inwards outwards, from the articular surfaces or 
central parts of the bones towards the periphery, and, second, 
those which accept the opposite progress, viz., from the periphery 
towards the centre. Among the former must be named Joly, 
for whom the pathological process means successively : firsts a 
dry arthritis of the lower tarsal articulations (the spavin-arth¬ 
ritis) ; second^ ankylosis of the inflamed articular surfaces 
(spavin-ankylosis); thirds a localized exostosis on the inner side 
of the base of the hock (spavin-exostosis); fourth^ extension of 
the process beyond the lower tarsal articulation with irritation 
of the circumference of the superior tarso-metatarsal and tarsal 
joints. For Prof. Eberlein the process differs. The first lesion 
is an osteoporosis, rarifying osteitis, involving the cuniforms 
and metatarsals, followed by a condensing osteitis, with chon¬ 
dritis and proliferation of cartilaginous cells and followed 
sooner or later by ankylosis. Sometimes the inflammation 
passes directly from the bone to the periosteum of the small 
tarsal bones and gives rise to the development of exostosis on 
the inferior parts of the hock. 
The interest promoted by such diversity of opinion was 
stimulated recently at the Societe Centrale by a very interesting 
paper presented by the learned professor of Alfort, Mr. Barrier, 
who among his conclusions says that spavin consists essentially 
in a chronic, dry arthritis, generally ankylosing and difforming, 
which starts in the articulations of the infero-internal part of the 
hock and has a tendency to spreaa to the superior from below 
upwards and from inwards outwards. 
