658 TRANSACTIONS OF SECTION I. 
Section I.—PHYSIOLOGY., 
PRESIDENT OF THE SEctION—A. D, Water, M.D., LL.D., F.B.S. 
THURSDAY, AUGUST 1. 
The President delivered the following Address :— 
On the Action of Anesthetics. 
Tue duty laid upon me by the Chair which I have the honour to occupy to-day 
is in the first place to copy the example of my predecessors by submitting to the 
Section some distinct and definite contribution to the advancement of science. 
And inasmuch as the subject has firmly held my attention during the last 
fifteen years, | am naturally led to name Anesthesia as the title of my Presiden- 
tial Address to the Section of Physiology. 
With due regard paid to the fact that the audience to which the British 
Association addresses itself is not principally medical nor exclusively scientific, 
I shall deal with the subject in a manner that may,I hope, justify my opinion 
that it is a subject capable of being usefully considered by all educated minds. 
And surely, quite apart from its value as an illustration of the method of 
physiological inquiry, the subject is one with which any educated man may well 
desire to possess some rational acquaintance, since every one of us may some day 
require the saving boon of anesthesia. 
Most people have some idea of what is meant by an anesthetic, and will recog- 
nise by name at least one anesthetic drug—chloroform, It is even probable that 
the first stranger whom you should meet in the street might also name ether and 
‘gas’ as being anesthetics. And pretty surely he would also know that the use 
of an anesthetic is to abolish pain. But if you were to tell him that a plant can 
be anzsthetised—that seeds can be chloroformed or etherised—he might very 
possibly express surprise. 
The popular notion of an anesthetic, in conformity with the literal meaning 
of the word, is that it is something that abolishes sensibility and takes away 
pain. But how, then, can a plant be chloroformed? Does that mean that a plant 
is sensitive and can feel pain as we do? Well, probably not; nevertheless it is 
very certain that a plant can be anzesthetised, and when you have properly appre- 
ciated what this means I think you will admit that our notions of vital processes 
and of their anesthesia by ether, or by chloroform, or by a host of other reagents 
have been considerably widened. For we shall then have realised that the state 
of a person or of an animal rendered insensitive of pain by an anesthetic is a 
particular instance of the general principle that all protoplasm—vegetable as 
well as animal—is liable to be immobilised—put to sleep—more or less com- 
pletely—temporarily or permanently—by the action of substances which we 
therefore designate as anesthetics or narcotics. A volatile narcotic, like ether or 
chloroform, gets to the living cells of a plant by direct diffusion; in the case of 
ourselves and of the higher animals it gets to the living cells by the channels 
of respiration and of circulation. The molecule of chloroform (or of ether) is 
