594 STRING-HALT-ITS DOUBTFUL PATHOLOGY. 
upon the limb ? Or should the uleer ehance to heal (which 
is barely possible), and the part become covered -with a dense, 
smooth deposit (cburnated), would there then be string-halt? 
If there was, it certainly Avould not be from an ulcer. I 
certainly think that we may safely banish from our minds 
the idea of articular ulceration being the cause of string- 
halt. I have dissected many ulcerated hocks, but I am not 
aware that string-halt could be traced, in any one instance, 
to disease of this nature. 
In the next place, let us see whether that wdiich Dr. Bus- 
teed describes as an ulcer is in reality one. I scarcely need 
state what are the characteristics of an ulcer. The doctor, 
and most of the readers of the Veterinarian, are no doubt 
quite familiar with the nature of such a sore. They all know 
very well that it means a solution of continuity of the parts 
so affected, and that on its surface is usually found a dis- 
charge, varying in appearance and consistence according to 
the tissues involved. This discharge is rarely colourless, 
and very often is fetid, indeed alw^ays so when bone -is in¬ 
volved, and when cartilage is breaking up and liquefying, it 
may assume a greenish aspect. If such ulcers as the doctor 
describes had really existed, would not the synovia he so 
frequently alludes to have been discoloured; and w'ould he 
not have adverted to this had it been so ? I have no doubt 
he would. But the inference to be drawn from his remarks 
on this fluid, seen when exploring the interior of the hock- 
joint, is that it was normal; and in this respect I believe 
he was correct. Nor can I believe that the so-called ulcers 
had anything whatever to do with the production of string- 
halt. Then if the depressions the doctor met with on the 
articular surface of the astragalus, and occasionally on that 
of the tibia also, varying in size and also in outline, having 
irregular borders, are not true ulcers, what are they ? Why, 
simply those parts of the articulations upon which cartilage 
was never developed. They were, I have no doubt, con¬ 
genital. Such places are more commonly met with on the 
articulations in question than upon any other in the whole 
skeleton of the horse. But I have often seen such peculi¬ 
arities on the articular surfaces of the glenoid cavity of the 
scapula, also that of the humerus and the opposing articu¬ 
lations of the ulna and radius. These all vary, like those 
upon the tibio-astragalan articulations generally, both in size 
and outline. 
It may, however, be asked if we do not meet with instances 
of ulceration of the joints in which the synovia is not dis¬ 
coloured, or, at any rate, but very slightly so ? I answer in 
