222 OBSERVATIONS ON THOROUGH-PIN. 
to the case. It occurred above four years ago, and the subject of 
it was a troop horse of the Inniskilling Dragoons, well bred, and 
of a wiry make ; and his hocks were not by any means of bad 
shape, but, on the contrary, evinced good formation : yet they 
suffered from thorough-pin; and this circumstance may be partly 
attributed to the fact of his being a hot-tempered animal in the 
ranks, and would attempt, by frequently plunging forward, to leave 
them. It was after rather a long and severe field-day that the 
horse was reported to the veterinary surgeon of the regiment for 
being stiff in the off hind leg ; and on examination a tumour was 
found in the seat of thorough-pin, and it exhibitted “ a spread out 
aspect” along the course of the flexor pedis; the parts also were 
hot, and tender to manipulation. If my memory does not fail me, 
rest was given to the animal, and a high-heeled shoe was placed 
to the foot of the leg affected; fomentations were also applied to 
the tumours. This was followed up for some days; afterwards a 
blister was rubbed on the tumours, which acted well. The case 
seemed to be progressing most favourably : the heel of the shoe 
was gradually allowed to resume its usual height; and eventually 
the horse became sound. But this soundness did not last long ; 
for, a day or two after being sent to duty, the tumefaction became 
larger—even attained the size of a goose egg—and lameness was 
again evidenced. The horse was placed under treatment a second 
time ; and when the inflammatory action was subdued, a seton was 
inserted immediately over the thorough-pin on either side : it was 
allowed to remain in for two or three w r eeks, when it was with¬ 
drawn, and the parts were well blistered. When the effects of 
the blister had subsided, the patient was ordered exercise, which 
was by degrees increased. Ultimately he was returned to his 
duty as being sound, and he has continued in that state up to the 
present time. I may also remark that, in a few months time after 
he became sound, it was with difficulty that any one could detect 
that he had been treated for thorough-pin, no blemish existing, 
and the tumour that remains is very trivial in size. I can also 
affirm that I have seen setons act most favourably in cases both of 
bog-spavin and thorough-pin ; and they are truly worthy of trial in 
cases where lameness is produced by either of these diseased 
conditions. 
As to how setons operate, it may be supposed that they cause 
a deposition of lymph in the vicinity of the parts affected, on 
which it imparts pressure, causing them to resume gradually 
their natural dimensions, the deposit of lymph being present some 
time before it eventually becomes absorbed, and during its ex¬ 
istence supports the capsular ligament and bursa ; and by the time 
it does become removed by absorption, in many cases the bursa 
