490 
ANIMAL PATHOLOGY. 
which has no connexion with the manner in which the operation 
is performed ; and the cause of which is buried in obscurity. 
Near, or at the point of section above and below, a medullary or 
harder-constituted tumour begins to be formed. In some cases 
it attains the size even of a filberd. It is exquisitely tender; and, 
situated where it is, and projecting considerably under the inte- 
gument, the horse is continually striking the part with the oppo- 
site foot, and sometimes falls from the acuteness of the pain. 
These tumours or ganglions — they are sensitive nerves which are 
divided — are of a pearly-w'hite colour, hard, creaking under the 
scalpel, and, at the base, confounded with the cellular substance 
on which they are placed. They sometimes are continuous, or 
connected with the superior portion of the nerve by numerous 
fibrils, evidently nervous; sometimes they are thus connected 
with the inferior portion — occasionally with both, and at other 
times there is but one ganglion placed midway between the ends. 
They appear to be abortive attempts at re-union. There is but 
one course to be pursued. The horse must be cast ; the con- 
nexion of the ganglion with the divided nerve cut through, and 
the tumour dissected out. 
The Re-union of the Nerve . — On the question of the reproduc- 
tion of the nerves there is now no manner of doubt ; and, in fact, 
if veterinary surgeons had possessed any records of their own, 
or if they or their proceedings had been deemed worthy of notice 
by physiologists, the question would long since have been settled. 
A horse is lame — he undergoes the operation of neurotomy — at 
the expiration of an uncertain time the lameness returns, and he 
is destroyed. What, in the majority of cases, do we find ? Why, 
that the nerves had united — that new veritable nervous sub- 
stance was interposed. It could not be distinguished from the 
common substance of the nerves by the eye ; and Reil, an inde- 
fatigable and accurate physiologist, put it to a chemical test. It 
is well known that the neurilema and cellular substance generally 
will dissolve in nitric acid, but that the nervous matter resists 
its corrosive power. He immersed a portion of apparent nervous 
substance, which had been produced between the divided extre- 
mities of a nerve, in the acid, and it could not be dissolved. 
Caution . — Our object frequently is, to render that re-union as 
distant as possible, and we have but one means of effecting this 
purpose, namely, by excising a considerable portion of the nerve, 
whether matacarpal or radial. Meyer found, that if he removed 
a line, the reproduction was not effected in less than three weeks, 
and when two lines were taken away, two months elapsed before 
the union w 7 as complete. 
Soundness . — Can the horse that has undergone the operation 
