History of the Operation.—­It is to two English veterinarians that we owe the introduction of the operation to the veterinary world.  In 1819 Professor Sewell announced himself as the originator of neurotomy.  This claim was disputed by Moorcraft, who appears to have successfully shown himself to be the real person entitled to that honour, he having satisfactorily performed the operation on numerous animals for fully eighteen years prior to Professor Sewell’s announcement.  It appears that Moorcraft left this country for India in 1808, having practised the operation in more or less obscurity for some six or seven years previous to that.  After his departure neurectomy, as introduced by him, either died away in repute, or was not made by him sufficiently public to become a matter of general knowledge.  To Professor Sewell, therefore, although not the actual originator of the operation, belongs the honour of making it public to the veterinary profession.

In 1824, five years after Sewell’s introduction, we find it practised on the Continent by Girard.  We gather, however, from the writings of Percival and Liautard, that both in this country and on the Continent the operation was for several years largely in the stage of experiment.  Unsuitable subjects were operated on; the work afterwards given to the animal improperly adjusted to his altered condition; and the bad after-results of the operation almost ignored by some, and greatly exaggerated by others.  In fact, some long time elapsed before veterinary surgeons allotted to the operation that measure of credit which the results following it warranted.

The Object of the Operation is to render the foot insensitive to pain, and to give to an otherwise incurably lame animal a further period of usefulness.  After the operation, as time goes on, this object may become defeated by the reunion of the divided ends of the nerve.  In that case, neurectomy must necessarily be performed again.

The Operation.—­Two forms of neurectomy are recognised—­the high operation and the low.  The low operation deals with the posterior digital branch of the plantar nerve, and the high operation with the plantar itself.

It is the latter operation with which we shall deal first.  In our opinion it is that most likely to be followed by satisfactory results.  The area supplied by the posterior digital is mainly the posterior portion of the digit.  Thus, unless the cause of the lameness is diagnosed with certainty to be situated somewhere in the posterior region of the foot, section of the posterior digital alone will not give total insensibility to pain.  Added to that, we may remember this:  Below the point at which the digitals branch off from the plantar there is always more likelihood of the part we are attempting to render insensible being supplied by another and adventitious branch, or a branch that, as regards its direction, is abnormally distributed.  As a last consideration, we may say that the higher operation is the easier to perform.