OPERATIONS—NEUROTOMY. 451 
and upon the vessels, round the leg before the operation, thereby press- 
‘ing on the nerve and cutting off the supply of blood. This would prob- 
ably deprive the leg of all sensation. The most severe part of this 
method of periosteotomy would be the after-consequences. The incised 
tumor would inflame; the vacant channel would have to unite. The 
ane would occasion agony, the other be probably attended with violent 
itching. The limb, therefore, should be bandaged, even though a wound 
upon the horse’s body does not do so well when covered up. The band- 
age, however, will prevent the animal from injuring the sore leg with the 
opposite shoe, which a horse may be provoked to attempt by that irrita- 
tion which attends the healing process. 
OPERATIONS—NEUROTOMY. 
Neurotomy is the division of the nerve which supplies the hoof of the 
fore leg with sensation. The foot of the horse being moved through 
tendons by muscles from above, and having in itself no muscular power, 
obviously has no occasion for a motor nerve. Consequently the nerve 
running to the foot is wholly sentient. It is the means of communica- 
tion through which pain or pleasure is transmitted from the hoof to the 
brain. 
To take away a portion of this nerve is evidently to separate the 
medium of such communication. Feeling can no more travel along a 
divided nerve than electricity can along a broken wire. The knowledge 
of this fact has led to a portion of the nerve being excised; and the 
doing of this has been named neurotomy. 
A nerve is a very compound structure. It is composed of numerous 
fine filaments or small threads bound together by a cellular sheath called 
neurilema. Healthy nerve feels firm, and has a brilliant white appear- 
ance; unhealthy nerve is of a yellowish tint, and is of a less solid texture. 
The operation of neurotomy is certain relief, but that relief is of un- 
certain duration. The divided nerve, after a time, reunites. The junction 
thus formed carries on all the functions of the perfect structure; but a 
bulb is left behind at the place of union. This bulb is to be easily felt 
by pressing upon the seat of neurotomy externally with the points of 
the fingers; and the bulb being felt leads to a knowledge that the horse 
has been subjected to the operation. Neurotomy, therefore, can never 
be concealed, if pains are bestowed upon its detection. The operation, 
however, is not successful in every case. 
In some animals, the wound has just closed when junction seems to 
be formed between the divided ends of the nerve. The lameness then 
returns as acutely as ever. 
