May 11, 1871| 

NATURE 
29 

cession. Itis, as I have already said, not this calcula- 
tion which is called in question by M. Delaunay, but the 
fundamental idea. 
M. Delaunay says the fluid will have precisely the same 
motion as the crust; and that, because the new motion 
of the crust is so slow. Butit is clear that its slowness 
has nothing to do with the matter. The fact is that the 
fluid and the crust not being connected together by any 
solid connection, no motion, whether small (7.2. slow) or 
not, can be suddenly communicated from the crust to the 
fluidmass. Ifthe crust moved uniformly, as I have already 
said, and around a steady axis, the fluid might, after a 
lapse of ages, by friction and viscosity, acquire the motion 
of thecrust. But ifthe crust is continually shifting from 
this steady position, however slowly, the fluid cannot sud- 
denly acquire the new motion, and the crust slips over it ; 
and the thicker or thinner the crust, the greater or less is 
the solid mass to be shifted, and the less or the greater 
the precession produced, If the internal mass obeys at 
once the shifting motions of the crust, that mass cannot 
be fluid, but must be solid, and have a solid connection 
with the crust ; in which case the whole question is yielded. 
Mr. David Forbes speaks of the “labour” M. Delau- 
nay has gone through in giving vent to his opinion. If 
the thing done is to be measured at all by the thing sazd, 
his labour must have been infinite ; for what he has said 
is animpossibility. He has evidently altogether mistaken 
the problem. Mr. Hopkins’s method stands unimpaired 
by his criticisms. Indeed Mr. Hopkins was not a man 
to advance a theory which could be apparently set aside 
by such slender means. JoHN H. PRatTr 

A THEORY OF A NERVOUS ATMOSPHERE 
U NDER the above title, Dr. Richardson, in a lecture 
published in the JZedical Times and Gazette of last 
week, suggests a new theory in respect to nervous func- 
tion. We propose in a few sentences to state simply the 
meaning of this theory. 
The earlier physiological writers on the functions of 
the nervous system were under the impression that the 
brain, spinal cord, and other nervous centres acted after the 
manner of glands, and produced or secreted, as they said, a 
liquid. They called this assumed secreted liquid the ner- 
vous fluid, and they considered that it charges the nervous 
system, some also supposing that it makes even a circula- 
tion through tubular nervous channels or canals. It 
was not an uncommon notion that the nervous fluid 
conveys nourishment to the organs of the body; but the 
most common, and indeed generally accepted, hypothesis 
was, that it acts as a means of communication between 
all parts of the nervous system, and is the communicating 
medium of the impressions and motions derived from 
the outer world. Attempts were made to measure the 
rate of motion through this fluid, how long it took to 
convey an impression by it from brain to muscle. 
The discovery of frictional electricity, the special dis- 
covery pf the electric shock by Cuneus, of Leyden, in 
1746, ard the after discovery by Galvani of the inductive 
action of the prime conductor of the electrical machine 
on the muscles of frogs, threw quickly into the shade the 
speculations of the earlier neuro-physiologists. It was as- 
sumed at oncethat there exists a true animal electricity, that 
there is production of electricalaction within the bodies of 
all living animals, that there is conduction, and, in short, 
every nechanism and method for the carrying on, if we may 
so say, of electrical life. The discovery of the electrical 
organs of the torpedo, the dissection of the animal, the 
descriptions of its nerves by John Hunter, and the experi- 
ments made by a very earnest investigator, Mr. Walsh, 
aidea greatly to establish the hypothesis which Galvani 
and his followers advanced, and which Volta, with the 
whoe force of his experimental argument, failed to 
demolish, 

Of late years the old hypothesis of the nervous fluid has 
been lost altogether, while the electrical hypothesis infi- 
nitely varied from its original and simple character, and 
infinitely varying with every new step of electrical dis- 
covery, has in a ceitiin sense retained its popular hold. 
It is true the hypothesis has rested on so much laboured 
obscurity that nobody has succeeded in making out 
of it a demonstration like the demonstration of the cir- 
culation of the blood, and no one has made it so simple 
that every scholar can read it when it is written, and 
every medical practitioner practise by it and act upon 
it as a known principle. It is true that since the time 
when Volta gave his undeniable proofs against the truth 
of the first inferences of Galvani, the best and most 
thoughtful philosophers have felt doubts as to the elec- 
trical character of living action, and have looked on 
Galvani’s construction of life as a beautiful crumbling 
Tuin rather than as a temple befitting the worship of the 
gods of nature ; and, lastly, itis true that whoever takes 
up to read the tomes or volumes of the most eminent 
writers on the subject of animal electricity is prone to lay 
them down again as he would the handles of a battery 
that master his will without appealing to his reason, 
All this is quite true.; but still the electrical hypothesis 
has, as we before said, held its place; no attempt has 
been made to replace it ; it has maintained around it a 
spell of fascination. 
The theory that has been suggested by Dr. Richardson 
is in some sense a return to the old view respecting nerv- 
ous action, and in some sense also is an extension to the 
nervous system of the physical idea of communication of 
motion by molecular disturbance. Ina few words, the 
author of the theory supposes ;that the blood, as it circu- 
lates in the vessels on which the structures of the body 
are constructed, yields a diffusible vapour or atmosphere 
which charges the nervous system surrounding the 
molecules of nervous matter and pervading the whole 
nervous organism. He attempts to formulate the physical 
qualities of this vapour; it is probably an organic 
vapour containing carbon, hydrogen, and nitrogen ; 
it is insoluble in blood, it is condensible by cold, 
diffusible by heat ; it is retained after death longer in 
cold-blooded animals than in warm-blooded, and longer 
in warm-blooded animals that have died in cold than in 
those that have died in heat; it possesses conducting 
power, and as a physical substance is susceptible of varia- 
tion of pressure ; it connects the nervous system in all its 
parts together ; it isthe medium of communication during 
life between the outer and theinner existence ; by the organs 
of the senses the impressions and motions derived from 
the outer world are vibrated into or through the nervous at- 
mosphere to the brain ; in the living and healthy animal the 
nervous ether, if we may so designate it, is in correct ten- 
sion, in the feeble it is diminished, in the dead it is absent 
or inactive ; in the waking times of the living it is most 
active ; it may be used up faster than it is produced during 
exercise ; it is renewed during sleep. 
On the supposition of the existence of a nervous ether 
or atmosphere as thus suggested, the author of the theory 
accounts for various phenomena connected with the 
partial or complete destruction of conscious, and even of 
organic life. The action of narcotic vapours is an illus- 
tration in point. It is assumed that these vapours— 
vapours of chloroform or alcohol, for example—taken into 
the blood and carried to the nervous system, become dif- 
fused through the nervous atmosphere, and by their 
presence interfere with its physical qualities and thus 
obscure function. “The foreign vapour that has been 
introduced benumbs ; in other words, it interferes with 
the physical conduction of impressions through what 
should be the cloudless atmosphere between the outer 
and the inner existence.” 
Carrying out in a different way the same line of 
thought, the author of the theory to which we have 
