LAMENESS IN HORSES. 
5 
Mayhew found the tendon of the perforans muscle “ perceptibly 
enlarged,” shewing “ indications of an inflammatory condition.” 
He cut into it, “ and from the incision pressure caused to exude 
a thick dark-coloured pus, of the consistence of cream cheese*.” 
The case being one of chronic date, and subject to the suspicion of 
taint from a malignant disease present, will perhaps be viewed 
rather in the light of a condition inveterate curb may run on to, 
than as affording an example of the ordinary pathology of curb. 
In a hock I myself dissected, supposed from its outward appear- 
ance to harbour a curb, I found a thorn, half an inch in length, 
sticking in the substance of the perforatus tendon, precisely in the 
seat of curb. 
For reasons I have already stated, viz. the rarity of the occa- 
sions afforded us for examining curbed hocks, I should not think of 
putting my opinions in opposition to the asserted disease of liga- 
ment in curb — either of the annular, or the external lateral superfi- 
cial, or the calco-cuboid ligament. All I can say on this subject at 
present is, that I have not met with disease of the parts in ques- 
tion ; and should feel inclined to view such disease, when present, 
rather as consecutive of, or collateral with, the thecal affection than 
in the light of the proximate cause of curb. 
The Cause of Curb, investigated, throws a good deal of light 
upon its nature It evidently consists in sprain or rupture of some 
part ; and this part I have shewn from my own observation to be, 
ordinarily, the cellular sheath and bursa of the tendo perforatus. 
A person takes his horse out for a day’s hunt, finds him drop all in 
a moment excessively lame behind, and afterwards, when he comes 
to search for the cause of lameness, he discovers he has thrown 
out a curb. The physiological history of an accident of this kind, 
therefore, is, that the animal, in going through some slough in the 
course of the hunt, or over some rough or deep fallow, or in taking 
some high or wide or awkward leap, or from stepping unawares 
into a rabbit-hole or mire, has, to save himself from falling while 
he maintains his pace, been compelled to put his gastrocnemii 
muscles suddenly, and perhaps unexpectedly, into instantaneous 
and vigorous action; the result of which has been stretch or “sprain,” 
if not laceration, of the cellular sheath of the perforatus tendon. 
Although hard galloping and leaping may be set down as espe- 
cial causes of curb, yet may the disease be produced in the entire 
absence of such causes. I have known more than one instance of 
horses throwing out curbs in the course of even walking exercise. 
I remember a four-year-old blood troop mare walking only from 
See Veterinarian, vol. xx, p. 15. 
