THEORY OF A NERVOUS ETHER. 
387 
sob, the moan, or the muscular rigor is the echo of the pain ; 
it is more, it is the outlet of the evil, the excess of vibration 
reflected, diverted, given forth. The infliction of mental pain 
is followed by tears, sighs, and other varied forms of grief ; 
these are, again, the echoes and the outlets of the evil. 
The tension of the nervous ether generally may be too high 
or too low ; it may be so locally , owing to local changes in 
the nervous matter it invests and charges. Under undue 
tension of the brain or cord, both closed firmly in by bony 
walls, the ether, under sharp excitation, may vibrate as if in a 
storm, and plunge every muscle under cerebral or spinal control 
into uncontrolled motion — unconscious convulsion. 
Lastly, the nervous ether may be poisoned ; it may, I mean, 
have diffused through it, by simple gaseous diffusion, other 
gases or vapours derived from without; it may derive from 
within products of substances swallowed and ingested, or 
gases of decomposition produced, during disease, in the body 
itself. But here a field of observation opens relative to the 
production of some forms of acute and chronic diseases on 
which I must not enter, were even space at command. 
I have tried, and I hope with success, to offer a simple and 
practical view of a very difficult subject. The philosopher 
may think the subject void, the public may think it obscure. 
There are many, I am aware, who will say that although the 
theory is reasonable it is comparatively worthless until more 
is known — until, in short, the physical character of the assumed 
nervous ether is demonstrated and certain definite phenomena 
are made manifest by its mediation. This criticism, which I 
should be the first to suggest, I am the last to ignore. I 
profess only at the present moment to submit a theory ; I look 
to experiment for the trial of the theory, its truth, its falsity ; 
and as it is a theory which experiment can slowly, but in the 
most striking and solemn manner, truly and faithfully try, I 
abide the result with leisure and contentment. 
