NEUROTOMY. 255 
each would be neutralized.” — Todd and Bowman's Physiological 
Anatomy. 
Return of Sensation. — So far as restoration of function in a 
nerve can be considered as proof of union of its divided ends, the 
notable experiment, so impressively set forth by our late Professor 
Coleman in his “ Lectures,” concerning the division of the par 
vagum in horses, inconclusive. If the nerves on both sides of the 
neck be divided at the same time, or within a short interval of one 
another, death becomes consecutive on the division of the last ; 
whereas, if an interval of three weeks be allowed between the 
operations, the animal survives. 
Neurotomy, as performed for lameness, proves the same thing in 
the case of excision of the substance of the nerve ; the difference 
being, that while after simple division the nerve takes but a month 
or two to have its union and function restored, after excision the 
time required for regeneration and restoration of function becomes 
lengthened in some sort of ratio to the quantity of nerve excised. 
MEYER, who instituted some experiments to illustrate this, found 
that when he excised one line in breadth of nerve, the reproduc- 
tion occupied three weeks ; and when two lines’ breadth were cut 
out, two months. Mr. Sewell found, in cases of entire section of 
the nerves of the limbs of horses, that sensation returned in about 
a couple of months ; but that when a portion of nerve was ex- 
cised, the period of restoration and return of feeling could by no 
means be calculated with any certainty. In a horse I neurotomized 
many years ago, belonging to the Artillery, sensation and lameness 
returned in two years, and he was in consequence sold, unfit for 
further service. But, in a horse of my own, on which .1 operated 
for navicularthritic lameness (whose case is mentioned in vol. xx), 
and thereby rendered sound, after having ridden him myself for 
upwards of two years, and then parted with him, sensation had 
not re-appeared. So far as the return of lameness is the question, 
one of the most extraordinary cases we have on record is that 
(Case I) of the late Mr. Castley (referred to in vol. xx), wherein 
the horse neurotomized returned to his duty, as a troop-horse, a 
month after the operation, and continued to do his duty for eight 
years afterwards ; and even at the expiration of that length of 
time was not sold on account of any failing in his ci-devant lame 
limb, “ but for old age.” Although lameness had not returned, 
whether sensation had or had not we are not informed. The 
two conditions, although closely allied, and for the most part de- 
pendent, are not altogether so. As was stated before, cases, 
no doubt, arise in which changes of such a nature occur, either 
in the structure or function of the parts affected with the disease 
