428 
ON THE OPERATION OF NEUROTOMY, AS 
CONNECTED WITH SOUNDNESS. 
I • 
By Mr. W. Simpson. 
“ Can a horse upon which the operation of Neurotomy has 
been performed, ever afterwards be considered sound V ? is a ques¬ 
tion I have often heard agitated, and upon which different opi¬ 
nions exist amongst those who rank high in our profession. Mr. 
Sewell, to whom the credit of rendering this practice beneficial 
decidedly belongs, has said in court, that no horse can be sound 
after this operation has been performed upon him ; and this opi¬ 
nion, I believe, is entertained by other eminent men. Before we 
admit such a sweeping assertion, let us pause awhile, and briefly 
consider the operation itself, some of the circumstances connected 
with it, and the diseases to which it is applicable. The meta¬ 
carpal, or their continuation the plantar nerves, are selected for 
division, according to the seat of disease, 8cc. I will superficially 
trace these nerves from their origin. The axillary, or humeral 
plexus, is formed by branches from the three last cervical and the 
first dorsal nerves; this plexus gives origin to several large nervous 
trunks; but, for my present purpose, it is only requisite to notice 
two,—the radial and ulnar: these nerves, being formed by the 
union of spinal branches, are, of course, motor and sensitive 
nerves, having nothing whatever to do with secretion or nutrition, 
I need not describe their course down the radius; suffice it to 
say, when they have gained the metacarpus, they take the names 
of internal and external metacarpal nerves; here also they lose 
one of their functions : they are no longer compound nerves, but 
simple nerves of sensation, for the power of locomotion resides 
wholly in the muscles which are placed above the knee; conse¬ 
quently the motor fibres of the radial and ulnar nerves are distri¬ 
buted there. When these nerves are divided, the foot loses all 
sensation: if pain existed before, it is now no longer felt; but 
the animal steps firmly on the ground, and without that tender¬ 
ness which so plainly tells us all is not as it ought to be: yet, 
notwithstanding this loss of sensation, the functions of secretion 
and nutrition, being dependent upon another system of nerves, 
remain unaffected; the hoof grows as usual, synovia is secreted 
as usual, and all the offices of the foot are performed as before 
the division of the nerves. And does sensation never return ? 
Yes; it does return after a period greater or less, according to the 
manner in which the operation is performed, whether it be a 
simple division or the excision of a portion: if it be merely a di¬ 
vision of the nerves, sensation is restored in about two months; 
