ch of the
nerve as is possible.

_Reunion of the Divided Nerve_.--We may say at once that 'reunion' in the
popular sense of the word does not take place. At a varying period after
section, however, we do get a return of sensation. This is brought about in
the following manner: The axis-cylinder of the nerve, still in connection
with the spinal cord, swells somewhat, and hypertrophies. The cells of this
hypertrophied portion show a great tendency to proliferate and produce
new nerve structure. This growing point splits, and gives rise to several
fibrils, which are new axis-cylinders. These commence to grow towards the
periphery, and, in so doing, grow through the cicatricial tissue that has
formed at the seat of the operation.

After passing through the cicatricial tissue (the amount of which tissue,
of course, controls the length of time that insensibility remains), the
growing axis-cylinders reach the degenerated portions of the nerve below
the point of section. It is along the track of the old nerve that the new
growths from the stump reproduce themselves.

The fact of the new growths having to pass through the fibrous tissue of
the cicatrix before they can gain the course of the old nerve, along which
latter their progress of growth is comparatively easy, affords ample
illustration that as large a portion as is possible of the nerve should be
removed when operating, in order to convey insensibility for the longest
time. After reunion, of course, nothing remains but to repeat the
operation.

_The Existence of an Adventitious Nerve-supply_.--While not exactly a
sequel of the operation, the fact that it is not discovered until after the
operation has been performed warrants us in mentioning it here. It is
not an uncommon thing in the lower operation to find that sensation and
symptoms of lameness still persist after section of the nerve. In many
cases this has been traced to the existence of an abnormal nerve branch.
In the higher operation this is not so likely to be met with. That it may
occur, however, is shown by the following interesting case related by
Harold Sessions, F.R.C.V.S.:[A]

[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol.
xii., p. 343.]

'In June of 1898 I saw a hunter suffering from navicular disease. After
carefully examining the leg, I advised the owner to have the operation of
neurectomy performed upon him. This he decided to do, and the horse was
sent to me about the be