s
(introduced hypodermically, by the mouth, or otherwise) upon the
internal organs, and more especially upon the cerebro-spinal axis.
Some chemical affinity between the remedy employed and the protoplasm
of the nerve cell is, of course, assumed to exist; and it is with the
enhancement of this affinity--this bond of union between the medicinal
solution and the nervous element--that we shall chiefly concern
ourselves in the following discussion.

By way of introduction, I may recall the fact that my attention was
directed several years since to the advisability of devising some
means by the aid of which medicinal substances, and more especially
anaesthetics, might be made to localize, intensify, and perpetuate
their action upon the peripheral nerves. The simple problem in
physiology and mechanics involved in this question I was fortunate
enough to solve quite a long time ago; and I must confess that in the
retrospect these undertakings in themselves do not seem to me of great
magnitude, though in their practical application their significance
appears more considerable. Herein lies, it may be, the explanation of
the interest which these studies excited in the profession at the time
of their publication. These things are, however, a part of medical
history; and I merely refer to them at this time because they have led
me to resume the solution of a far greater problem--that of
intensifying, perpetuating, and (to some extent at least) localizing
the effects of remedies upon the brain and spinal cord. I speak of
resuming these studies because, as far back as 1880 and 1882, I made
some attempts--albeit rather abortive--in the same direction.

In constructing the argument for the following study, I am beholden
more especially to three facts, the knowledge of which came to me as
the direct result of experimental tests. One may place confidence,
therefore, in the procedure which I have based upon these premises,
for at no point, I think, in the following argument will mere
affirmation be found to have usurped the place of sound induction.
Without anticipating further, then, let me specify as briefly as may
be the nature of these facts.

PREMISES OF ARGUMENT. _First Fact._--The amount of ether, chloroform,
chloral hydrate, the bromides, strychnine, and many other remedies,
required to produce physiological effects upon the cerebro-spinal
mechanism may be reduced by first securing a ligature around the
central portion of one