THEORY OF A NERVOUS ETHER. 
383 
more than the solid matter which the eye can see and the 
finger touch. The question to he considered, is — the nature of 
this agent. 
In nervous structure there is, unquestionably, a true nervous 
fluid, as our predecessors taught. The precise chemical composi- 
tion of this fluid is not yet well known, the physical characters 
of it have been little studied. Whether it moves in current 
we do not know ; whether it circulates we do not know ; 
whether it is formed in the. centres and passes from them 
through the nerves, or whether it is formed everywhere where 
blood enters nerve we do not know. The exact uses of the 
fluid we do not, consequently, know. 
It occurs to my mind, however, that the veritable fluid of 
nervous matter is not of itself sufficient to act as the subtle 
medium that connects the outer with the inner universe of man 
and animal. I think — and this is the modification I suggest of 
the older theory — there must be another form of matter 
present during life ; a matter which exists in the condition of 
vapour or gas, which pervades the whole nervous organism, 
surrounds, as an enveloping atmosphere, each molecule of 
nervous structure, and is the medium of all motion communi- 
cated to or from the nervous centres. 
The source of this refined matter, within the body, is, I 
think, the blood. I look upon it as a vapour distilled from 
blood, as being persistently formed so long as the blood 
circulates at the natural temperature, and as being diffused 
into the nervous matter, to which it gives quality for every 
function performed by the nervous organisation. In the 
closed cavities containing nervous structure, the cavities of the 
skull and spinal column, this gaseous matter, or ether as I 
have called it, sustains a given requisite tension ; in all parts 
of the nervous structure it surrounds the molecules of nervous 
matter, separates them from each other, and is yet, between 
them, a bond and medium of communication. 
When it is once fairly presented to the mind that during life 
there is in the animal body a finely diffused form of matter, 
a vapour filling every part — and even stored in some parts ; a 
matter constantly renewed by the vital chemistry ; a matter 
as easily disposed of as the breath, after it has served its 
purpose — a new flood of light breaks on the intelligence. Our 
own consciousness re-echoes to us the fact. Our experience 
assures us that between ourselves and the outer world there 
is, while we live, an intercommunicating bond which connects 
us with the outer world ; which is apart from the gross visible 
substances we call flesh, bone, brain, blood ; which in some 
way, nevertheless, is connected with both heart and brain and 
organs of sense ; which is made in and within our own organism ; 
