NEUROTOMY. 253 
of scissors, to effect the division of the nerve. Only the upper 
half of the blade b, as will 
be seen by the woodcut, 
is provided with a cutting 
edge. 
Between instruments of 
such different construction, 
although intended to answer 
similar purposes, there is no 
making any comparison. 
Nor is it needful for us to 
do so. All that we shall say, 
in passing any opinion on 
their merits, is, that in their 
way both exhibit more than 
ordinary ingenuity in their 
invention, and that the neu- 
rotomist who takes care to 
provide himself with one or 
both of them, will find him- 
self at the moment of ope- 
rating in the possession of 
an aid which will much sim- 
plify and shorten his under- 
taking. 
The Union of the 
divided Nerves takes 
place forthwith, provided 
those nerves are simply cut 
in two ; sensation — and with 
it lameness — returning in 
about a'month or six weeks : 
but if a portion of nerve be excised, immediate union is thereby 
prevented. 
In a series of experiments made on animals by Swan* to set 
the question of union of nerve at rest, he found that when a 
portion of nerve is removed the restorative process is set up the 
same way as when there has been merely division of a nerve ; 
and that this was, that the extremities of the divided nerve, par- 
ticularly the superior one, became thicker and more vascular : 
coagulable lymph, having the appearance of albumen, being poured 
out, and in a short space of time permeated by bloodvessels : 
then both ends of the effused lymph form an union, and anasto- 
mosing vessels shoot through it. Gradually, this intermediate 
* On the Local Diseases of Nerves. 
M m 
VOL. XXI. 
