STRING-HALT-ITS DOUBTFUL PATHOLOGY. 593 
practice, lias not observed string-lialt in association v’itli 
exostosis on tlie inferior anterior and inner surface of tlie 
hock? And they may have been able to trace the develop¬ 
ment of the latter with the occurrence and increase in in¬ 
tensity of the former, and have also believed (and very con¬ 
sistently so, in my opinion) that the string-halt was due, in 
such cases, to the sentient nerves of the part being irritated 
by this abnormal growth of bone (constituting spavin). I 
well remember two particular cases in which string-halt took 
place very shortly after the horses—subjects of this malady— 
had received a severe injury from falls. One of them was 
under treatment for a long time, during which he was fired 
over the upper part of the haunch of the affected limb, when 
he became quite free from lameness, but the string-halt was 
rendered permanent; still it in no way interfered with his 
general services. 
During the last twenty years I have post-morteni 
several horses that had been the subjects of string-halt. In 
one ease in particular, I noticed that the areolar tissue which 
invested the sciatic nerve, from a little below the sacral fora¬ 
mina to the point where it gives off the lesser sciatic, was 
considerably thickened, and, as compared with the same 
covering to the nerve on the opposite side, was of a palish- 
brown colour. I carefully separated the fasciculi of this nerve, 
but I could not discover that its fibres had been structurally 
interfered with. Still, the altered and condensed state of 
the investing tissue may have been a source of persistent 
irritation when the limb was moved. 
I have thus endeavoured to show that the exciting cause 
of string-halt is not, of necessity, located in one particular 
situation; but, for the effects to be continuous, the cause, 
whatever it may be, must be so also. This brings me to the 
eonsideration of Dr. Busteed^s ulcer, which he considers the 
only cause of string-halt. Now, can we conceive that an ul¬ 
cerated hock is likely to be the permanent cause of string-halt ? 
For argument sake, we will suppose that an ulcer on the upper 
articular surface of the astragalus is capable of producing 
such an effect; but then, is it likely to be persistent ? Is the 
ulcer to remain without an extension of its ravages year 
after year, producing this peculiar phenomenon, without any 
other inconvenience to the animal? I am sure that the 
doctor, upon a little reflection, will say, ^Aio, this cannot 
be.’^ Would not the ulcer, from its tendency to spread, gra¬ 
dually involve the whole or the greater part of the articular 
surface of the bone, and the horse therefrom become so 
acutely lame that he could not bear the slightest weight 
