After all, even though we may have fully decided the foot is at fault, our
case of lameness may remain obscure so far as a cause is concerned. Nothing
remains, then, but to acknowledge the inability to discover it, to advocate
poulticing, or some other expectant palliative measure, and to bring the
case up for further examination at no distant date. Where, though we
may have suspected the foot, we have not been able to definitely assure
ourselves that there the mischief is to be found, a further method of
examination presents itself--namely, subcutaneous injections of cocaine
along the course of the plantar nerves.

The salt of cocaine used is the hydrochlorate, 2-1/2 grains for a pony,
4 grains for a medium-sized animal, and 6 grains for a large horse. A
solution of this is made in boiled water (about 3 drams), and injected at
the seat of the lower operation of neurectomy.

It is advisable to first render aseptic the seat of operation, and to
sterilize both the needle and the syringe by boiling. A suitable point to
choose for the injection is exactly over the upper border of the lateral
faces of the two sesamoids, the needle being introduced behind the cord
formed by the nerve and accompanying vessels, and parallel with it.

It is possible that the vein or the artery may be wounded, but such
accident is of little importance. All that is necessary in that case is to
partly withdraw the needle and again insert it. It is advisable to use a
twitch.

When the needle is in position, the injection should be made slowly, and
at the same time the point of the needle should be made to describe a
semicircular sweep, so as to spread the solution over as wide an area as is
possible.