STUDY OF THE PHYSICAL CHEMISTRY OF ANAESTHESIA 
down as secondary factors, due also to the same primary cause as directly acting 
upon the nerve centres, produces the unconsciousness of sleep, of coma, or of 
anaesthesia. 
It is clear then that we must turn to a consideration of the effects of the anaes- 
thetic upon such constituents as are present in the cell, and as a preface to the 
consideration of the various theories which have been put forward, it may be well to 
point out that although anaesthesia in mammals means the abolition of consciousness, 
and the accompanying incapacity for the oroduction of sensation following peripheral 
stimulation of nerve endings, yet this effect only differs in degree from other effects 
which appear as the concentration of the anaesthetizing agent is gradually increased. 
The cortical nerve cells pass first under the influence of the anaesthetic, while other 
portions of the nervous mechanism are still active and amenable to stimulation. For 
example, the reflex nervous mechanisms throughout the medulla and cord are still 
active, such as those which regulate the respiratory and cardiac rhythms, peristalsiSj 
the condition of the vasomotor system, and the sphincters throughout the body, 
although the degree of activity is, in most instances, depressed. 
If the concentration of the anaesthetic be increased, however, these remaining 
portions of the nervous system also pass under the action of the anaesthetic, and 
death of the mammal ensues, usually from stoppage of the action of the nerve cells 
responsible for the continuance of the respiratory rhythm. 
Nor is it the cells of the nervous system alone which are affected by anaesthetics, 
for at increasing concentrations isolated mammalian tissues are affected, and their 
activities inhibited and finally stopped, as has been demonstrated experimentally for 
nerve fibres, for cardiac and skeletal muscle, and for ciliated cells. 
The same effects are demonstrable not only for mammalian tissues, but also in 
all living cells of whatever source, whether of vertebrate or invertebrate, of animal 
or plant, of the lowliest unicellular organism or of the highest mammal. 
This result is of importance, as clearly showing that the effect of the anaesthetic 
throughout the whole range of living cells is produced in some common fashion upon 
a constituent which is uniformly present in every living cell, and is not something 
peculiar to the nerve cell, nor explicable by some morphological arrangement present 
in the nerve cell and not present in other cells. 
The result teaches, for example, that no faith can be placed in a mechanical 
theory of anaesthesia, such as the withdrawal or profusion of the dendrites of the 
nerve cell, for this would yield no explanation of the similar action of anaesthetics 
upon other types of cell. 
The universality of the action of anaesthetics upon all living structures further 
narrows the field of search for the substance upon which the anaesthetic acts, since 
any occasional cell constituent may at once be removed from consideration, and only 
those left which are invariably present, 
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