238
the chloroform or diluting it in a mechanical inhaler is any guide whatever to the amount
of the anæsthetic a patient inhales or absorbs. Moreover, breathing through an inhaler is not
natural breathing.
8. The Commission has shown that the key to the safe administration of chloroform is
that the breathing be natural, so as to avoid struggling and any form of respiratory embarrass-
ment; and that it may be so the anæsthetic must be administered in an open cone or cap,
which is held far enough from the patient's face to avoid causing him to hold his breath or
struggle, and into which he is at first made to blow after each inspiration, the cap being
brought nearer to the face, and eventually quite close to it, as the chloroform begins to take
effect and he breathes regularly.
The two tracings dated March 6th, 1890, Nos. 3 and 4, Ludwig, show very conveniently
all the points claimed by the Commission. They demonstrate: (a) The gradual fall of
blood-pressure caused by chloroform inhalation, when the chloroform is properly given, so as
to entirely avoid struggling or holding the breath, &c. ( b) The value of reflex winking when
the eye is touched, as a guide to the state of anæsthesia. When this point is reached, the
subject may, as a rule, be said to be ready for operation, and this, it will be seen from the
tracings, occurs long before the fall of pressure, if this be regular, reaches a dangerous stage.
(c) The effects of pushing chloroform till the stoppage of the respiration, the heart being un-
affected till long after this stage is passed. (d) The slowing of the circulation and fall of
blood-pressure caused by irritation of the vagus. No one doubts that the vagus has the same
action in man as it has in animals. (e) The effect of electrical irritation of the vagus when the
respiration has ceased; and the slowing of the circulation, which retards the conveyance of
chloroform, to the nerve centres. It is not difficult to understand how slowing of the circula-
tion necessarily retards the conveyance of chloroform to the medulla. For example, if the
pulse is sixty, and sixty atoms of chloroform are conveyed to the brain in a minute, only thirty
atoms a minute will reach the brain (other things being equal) if the pulse is reduced to thirty
by stimulation of the vagus. Tracings 3 and 4 of the effects of ordinary chloroform inhalation
are identical up to the point where the respiration ceased. Tracing 3 then shows that the
breathing having entirely ceased, stimulation of the vagus slowed the circulation from eighty-
six to forty-two a minute and saved the dog's Tracing 4 shows how, after the stoppage
of the respiration, when artificial respiration was not employed and the vagus was not irritated,
the heart's action gradually ceased. Both tracings show how useless it would have been to
have taken the action of the pulse as a guide. When the pulse failed, as it did at the end of
Tracing 4, it was a sign of impending death. The two tracings demonstrate that by taking
the respiration alone as a guide, danger could have been averted, as it always can be in the
human subject under chloroform, if the breathing is carefully kept free. It is remarkable that
in these two experiments the chloroform was given undesignedly or precisely the same length
of time, viz., 4.42 minutes. Considered by the light of the work of the Commission, these
tracings prove incontestably that the slowing of the heart and circulation through the stimuli
tion of the vagus is a safeguard in chloroform poisoning. The symptoms—pallor and loss of
pulse—produced in a similar manner in man are none the less signs of the greatest danger,