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intake of an overdose, and not because there is any action on the heart peculiar to any particular
degree of concentration. The Hyderabad Commission's experiments, where chloroform was
injected into the large veins of the neck, show that even pure chloroform in the blood does not
stop the heart till after it has paralysed the respiration.
It is abundantly proved that diluted chloroform, provided it is not too dilute, gradually
causes an accumulation of chloroform in the blood sufficient to produce first narcosis, then
cessation of the respiration, and finally death. A higher concentration can only bring about
the same sequence of events in a shorter time. The higher concentration cannot have any
action on the heart peculiar to itself, unless it be that the more concentrated vapour gives rise
to spasm of the bronchioles, or in some other way impedes the oxygenation of the blood, and
so, pace Professor MacWilliam, affects the heart injuriously, it is impossible that the concen--
trated vapour can act upon the heart in a mysterious way before it gets into the blood. It is
clear also that the harmless dilute vapour must in time accumulate in the blood; otherwise it
could not bring about narcosis and cessation of the respiration But we may well enquire why,
when this point is reached, it does not then have the same effect as the concentrated vapour?
The truth is that the concentrated vapour interferes with natural respiration and the natural
oxygenation of the blood; and in the Hyderabad Commission's report, and in that of
Dr. Cushny, it is remarkable that there is an utter want of uniformity in all experiments where
normal respiration is interfered with, and complete uniformity in all experiments with chloro--
form inhaled in the natural way. The concentrated vapour of chloroform cannot be voluntarily
inhaled by man or by animals. When a patient or an animal is forced to inhale concentrated
vapour involuntarily, or if it is pumped into the trachea, the danger lies in the fact that when
it is desired to stop giving the chloroform it is entirely beyond control, and though the
administration be discontinued, the discontinuance does not actually commence until the
residual amount far down in the lungs has been got rid of. Long before this can be effected
either by artificial respiration or in any other way, the patient may be dead.
Dr. Cushy and the Hyderabad Commission are in complete accord with regard to the
practical administration of chloroform, and have them same object in view. That object is the
dilution of the anæsthetic to a point consistent at once with full anæsthesia and with safety
Dr. Cushny attains this end by means of an apparatus. The Hyderabad Commission attains it
with equal certainty by giving the chloroform in such a manner as to ensure normal regularity
of the respiration. Lister has demonstrated that the strength of vapour which can be naturally
inhaled on an open cone or on a towel is from two to four per cent. With regular breathing,
if the number of respirations and the number of cubic feet of air inspired in a minute are
known, the dose of chloroform inhaled in a given time can be estimated with almost uniform
a c c u r a c y . B u t i f t h e b r e a t h i n g i s i r r e g u l a r , t h e i n t a k e o f c h l o r o f o r m w i l l b e v a r i a b l e a n d
uncertain, and there will be danger in proportion to the uncertainty of the dose. Lastly, if the
vapour is concentrated so as to compel the patient to struggle and hold his breath, the risk of
overdosing is enormous. Asphyxia ensues and leads to deep gasping inspirations and rapid
and, may be, irremediable poisoning. It follows from these considerations that the strongest
vapour of chloroform which can be inhaled with regular natural breathing constitutes the safe
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