PRESIDENTIAL ADDRESS. 659 
drawn into the lungs with the inspired air, passes from the pulmonary air to the 
pulmonary blood, combines with its corpuscles, is thus carried first to the heart 
and then distributed with the blood to all parts of the body; in the capillaries 
the molecule of chloroform parts company from hemoglobin, passes from the 
blood to the tissues and tissue fluids and enters into combination with the living 
cells which it immobilises more or less profoundly, temporarily or permanently. 
The various kinds of living cells that constitute our organs are unequally suscep- 
tible as regards the immobilising effect of this general invasion of the system by 
the narcotising molecules. 
Of all the cells of the body, the most labile, and therefore the first immo- 
bilised, are the master cells of the body—the cells of the grey matter of the 
brain, that is, the seat of sensation and the organ of voluntary motion. The most 
stable, and therefore the last immobilised, are the executive cells of the body 
that constitute muscle and nerve. The order of lability from greatest to least is 
as follows: Brain; spinal bulb and cord; terminal nerve cells; cardiac muscle ; 
skeletal muscle; nerve fibres. And while all living cells and tissues of the body 
are subject to the immobilising action of narcotic substances, their individual 
differences of susceptibility are such that, whereas one part of chloroform in 
5,000 of blood is sutticient to immobilise cortical nerve cells, a nerve fibre requires 
a more than tenfold eftective mass of chloroform before exhibiting any falling-off 
of its normal excitability. 
Let us now briefly consider what happens when a patient is anzsthetised by, 
say, chloroform in the usual manner by inhalation of an unknown mass of vapour. 
The inhaled vapour, more or less diluted in air, diffuses into, and is distributed to, 
the entire body by the circulating blood. The lymph bath that surrounds and 
permeates all the tissues and cells of the body becomes a weak solution of chloro- 
form in water, and gradually within that weak chloroform atmosphere the most 
labile parts fall under the immobilising effect of the anesthetic, first the organ 
of conscious sensation and movement—the cortical grey matter of the brain— 
then the organ of unconscious reactions, the medullary grey matter of the 
spinal bulb and cord. So that the order in which the effects unfold themselves 
are (after a brief stage of excitement or mobilisation) first a suppression of 
sensation and voluntary movement, then a suppression of reflex and automatic 
movements, inclusive of the movements of respiration. Finally—and if this 
finally is reached the immobilisation can no longer be recovered from—the heart 
stops beating. The patient is dead. 
From life to death by the way of anesthesia there are three principal finger- 
posts dividing the journey into three stages. Of these three finger-posts two are 
to be carefully watched for; the third should never be sighted. 
During the first stage of aneesthesia— commencing, it may be, by some amount 
of preliminary agitation—sensation and voluntary motion become suppressed, 
while reflex and automatic movements are preserved. The finger-post between 
this first stage and the next is quite clear: if when the conjunctiva is touched the 
eye winks the anesthesia is ‘light’; if the eye does not wink the anxsthesia is 
‘deep.’ 
Dating the second stage of anesthesia not only voluntary but also reflex 
movements (of which the conjunctival reflex is the most convenient indicator) 
are wholly suppressed, while the automatic movements of respiration persist. 
This is the degree of anesthesia required for any major surgical operation, and is 
therefore frequently spoken of as surgical anesthesia. The finger-posts to its 
boundaries are: on this side the conjunctival reflex, on that side the movements 
of respiration. 
The third and last finger-post—arrest of the heart’s beat—should not be passed. 
Arrest of the pulse signifies an almost hopeless state. The time of grace 
between arrest of respiration and arrest of the pulse from which recovery is almost 
hopeless is very brief indeed—hardly more thun a minute. The doctrine of the 
Edinburgh school—watch the respiration, not the pulse—is sound doctrine. 
Stoppage of respiration means danger ; stoppage of the pulse means death, 
I think this sketch, rough as it is, will be sufficient to bring before our minds 
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