626 
NARGRE 
[OcTosBER 26, 1899 
sea shore, and think he has penetrated the secrets of ocean. 
After all our searchings and all our efforts, to-day we can hardly 
say more. The shades that surround us are as deep as in the 
time of Newton; and in this universe, vast and obscure, at 
most scattered glimmers of light, few and far between, reach 
our straining eyes. 
We need all the co-operation of all men of science, of all 
nations, to dispel some of these shades. What madness it would 
be not to unite, not to walk hand in hand, but to strive apart ! 
The reward of this union will be above all price: the conquest 
of truth, the control of brute matter, the gift of a life less pre- 
carious and less painful to man, feeble man. 
And so you see what we should think of those self- 
styled patriots and nationalists, who speak of French science, 
English science, German science, as if science were not inter- 
national, and lifted high above our vain frontier limits. 
To the history of nerve-waves many workers of diverse 
countries have contributed their share; as with every great 
scientific problem, every country of the world has taken part in 
its solution. But before I go on, let me pray your indulgence 
for treating of so arid and so difficult a subject before you. 
Te *e 
The world around us presents itself in different aspects to 
the eyes of the student and of the layman. 
in them, and commonly defined by the impressions made on 
our senses. A given object is warm, light, electrified, heavy, 
and so forth; and every one thinks that heat, light, electricity, 
weight, are so many realities, distinct from the object itself. 
But the man of science conceives matters otherwise. For him 
this vast universe is formed of an indefinite ‘‘ something ” termed 
««Energy,” and he knows that this force may have different mani- 
festations in motions of diverse kinds. Weare almost justified 
in saying that ‘‘ Energy is one” ; that its aspects appear to our 
senses so different because the various movements of this energy 
have not all the same qualities. They differ in number, in 
frequency, in rapidity, in form; and according to these different 
modalities which we perceive, and to their results, we have heat, 
light, electricity, attraction. 
The movements of this energy are all transmitted in the same 
way, by wave-motion—“ undulation ” or “‘ vibration,”’ as we call 
it; and the physicists, by wonderful research, in which the 
highest mathematics must be utilised, have succeeded in de- 
termining the forms of certain kinds of these waves. And even 
those motions of energy which we do not so well understand, we 
are justified, by what we do know, in regarding also as wave- 
motions or undulations. 
I need not dwell on this phenomenon of undulation or vibra- 
tion. We all know the simple case when a pebble is dropped 
into still water ; and the surface, which was smooth as a mirror, 
now shows a series of disturbances propagated in ever-widening 
concentric circles. In each oscillation we see two periods: in 
the one the water recedes from the primitive plane of the mirror, 
in the other it comes back to it again. The former is the ferzod 
of departure, the latter that of veturn. 
So, if we hit a hanging weight, a pendulum, the shock at 
once removes it from its position of equilibrium, and it recedes 
further from it (period of departure) ; then it comes back again 
to its starting point (period of return). What I have called 
undulation and vibration are two names for the same _phe- 
nomenon, of the greatest diversity in form, but essentually due to 
the wave-motion of a fluid. Though, if you will, this fluid, the 
ether, be of very hypothetical character, we will take it for 
granted here, and say that heat, light, electricity, gravitation, 
are all wave-motions of the ether. 
Consequently, the outer world in its infinite diversity of 
aspect, in form and in colour, is the sum total of the various 
vibrations of force. These vibrations, most diverse in character 
and in intensity, act upon the living organism, and produce 
sensations therein. Now it is probable that, as I shall try to 
show you directly, these vibrations of the outer world only act 
on our senses by evoking within us another kind of vibration, 
to which are due sensation and perception. Thus the nerve- 
wave is revealed to us as the goal and the final term of the 
vibrations of the external world. Were there no nerve-wave, 
though, no doubt, all these external vibrations would still exist, 
still they could produce no effect on us. In virtue of its own 
proper vibrations, the living being becomes the microcosm, the 
recipient of the diverse vibrations of the macrocosm, the universe : 
NO. 1565, VOL. 60] 
The layman sees } 
external objects, endowed with properties apparently inherent: 
by these vibrations only is the universe accessible to our under- 
standing. Thus you see what of interest lies in the study of this 
nervous vibration, since through it the outer world is known to 
us, and through it we have the power to act on the outer 
world. 
Il. 
This study is no new one; I should trespass beyond the 
limits of your courteous attention were I to try and recount all 
the classical facts that are well known at present. Yet, that 
you may understand the new facts I am coming to presently, 
I shall have to give youa short summary of some of these classical 
facts ; and I hope that despite their being so well known, they 
will not be devoid of interest to you. 
The nervous system is made up of distinct elements, each con- 
sisting ofa cell, with very long fibrous outgrowths. These cells. 
with part of their outgrowths are compacted into the central 
nervous system, while the rest of the outgrowths are produced 
into strands, the peripheral nerves. An elaborate microscopical 
analysis of the last few years, largely due to Golgi and to 
Ramon y Cajal, have shown that the total number of processes 
is countless. Each cell sends forth at least one outgrowth, the axzs 
cylinder, which remains unbranched except at its very termin- 
ation ; while the others, like the branching roots of a forest tree, 
spread out in all directions, so that they interlace with those of 
its neighbours. Thus all the nerve-cells are in communication ; 
the disturbance of one may affect all. And this disturbance 
may,be propagated far and wide ; for in the peripheral nerves 
pass out the axis-cylinders, which separate ultimately and get 
up to the very tips of the limbs, to the skin, the entrails, the 
muscles, and the glands. Think of the whole surface of the 
skin as provided with little nerve apparatuses, all capable of 
vibration and of transmitting their undulations through the 
sensory nerve-fibrés to the nerve-centres; of the nerve- 
centres as possessing processes like the sensory fibres, 
whereby to transmit their orders to the muscular and 
glandular organs; and you will be able to realise the 
part played by the nerves in the life of the organism. It is a 
vast telegraphic apparatus, to receive, by its sensory receptive 
mechanism, all impressions from without, and to transmit, by its 
transmitting mechanism, corresponding messages to the organs. 
of motion, the muscles. And, since all the nerve-cells are, 
moreover, in communication with one another, and since every 
living cell is in relation with nerves, we may sum up the rela- 
tions of the living organism in this general formula : through the 
nervous system, any one living cell reverberates in every other 
cell, and is reverberated to by every other cell. Thus the living 
organism that possesses a nervous system is no mere aggregate 
of cells; it isan zvdivédual, all the parts of which co-operate 
for the common weal. 
The nerve-cell, together with its prolongations, has received 
the name of ‘‘ neuron”; we can conceive that by the inter- 
relations of all its neurons the living organism may be regarded 
as one gigantic neuron, sensible to all stimulations at the 
periphery, and answering them by stimulations of the motor 
apparatus, which are translated into acts of motion or of secre- 
tion. This sensibility and its motor response are linked by a 
phenomenon which we shall call for the present the ‘‘nerve- 
vibration ” or ‘‘ nerve-wave.” How far is this name justified ? 
This is the question that we have to deal with. 
III. 
Let us for the moment make the assumption (which is not 
quite exact) that the phenomena are identical in the peripheral 
nerves and in the central nervous centre, and that what applies 
to the one will also apply to the other. 
We may, at least, accept them as analogous, since the axis- 
cylinder of the peripheral nerve is an expansion of the proto- 
plasm of the nerve-cell. True, the reactions of the peripheral 
and of the central nerve tissue are not identical; but their 
differences are probably in accessories, not in essentials. We 
may, therefore, boldly accept their analogy, if not their identity ; 
and we are justified in applying to the one the truth that we 
learn of the other. 
The pace at which an impulse travels along a nerve is well 
known since 1850. Strange to say, just two years before, a 
great physiologist, one to whom the science is indebted for 
some of its grandest advances, Johannes Miiller, declared that 
it was impossible for us to determine the speed of nervous 
transmission—an affirmation as imprudent as are all affirmations 
which proscribe formal conclusions to the science of the future. 
