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dogs either by primarily paralysing the heart or the respiration." "In most cases respira
-
tion stops before the heart's action." "The danger of death from stoppage of the respiratory
functions must be borne in mind in every case in which anæsthetics are given," &c. These
sentences show that we recognised the danger to respiration. At the very beginning of our
report we state: "Without going into detail, we may say that it soon became apparent to
us that chloroform administered to dogs and rabbits has a disastrous effect on the respiratory
centres; it is easy to kill one of these animals by pushing the chloroform till respiration is
paralysed. In observing the rate of the heart during these experiments, it could often be
determined by auscultation that its contractions were maintained after respiration had ceased.
It was apparent, however, that even when failure of respiration was more directly the cause
of death, the heart was, to some extent, simultaneously affected; there were even cases in
which the heart appeared to fail at least as soon, if not before, the breathing."
It is evident from this that we regarded the danger to respiration as a proved and
indeed a well-recognised fact; and our special object was to investigate the question of how
far chloroform was dangerous to the heart. The result of our inquiries was to convince us
that danger to the heart is at least an occasional occurrence, and one to be kept in mind in
watching a patient under the influence of chloroform. In summing up, we put the matter
thus: "The chief dangers are (1) sudden stoppage of the heart; (2) reduction of the blood-
pressure; (3) alteration of the pulse respiration ratio; and (4) sudden cessation of the respira
-
tion." In this enumeration we did nut intend to place the phenomena in the order of their
relative frequency or importance, although we admit the sentence might bear this inter
-
pretation were it not taken in connection with the statements quoted above from the beginnin
g
of the report. The question, then, narrows itself down to this: Does chloroform ever kill by
paralysing the heart? We assert that it may do so; the Hyderabad Commission hold that
it never does so, and that it always kills by paralysing the respiratory centres or, in their own
words, referring to experiments without recording apparatus: "In every case in which
chloroform was pushed the respiration stopped before the heart."
5. Before entering on an examination of the Hyderabad observations, we may
reiterate some of the points which our experiments seemed to bring out:—
(a) We showed that chloroform vapour has a paralysing effect on the muscular tissue
of the heart and indeed on all kinds of protoplasm, when directly applied. When the heart of
a frog was exposed to the direct action of chloroform vapour, it "became rapidly weaker till it
ceased beating." As regards the action on the mammalian heart we make the following
quotation from our report: "With a similar view, a method was devised for warm-blooded
animals. Rabbits were first used and afterwards dogs. The animal was anæsthetised, then
the trachea was opened, a tube introduced, and artificial respiration begun by means of a
double acting pump (one cylinder forcing air in and another sucking it out). By an arrange
-
ment of India-rubber tubes, chloroform or any other anæstheic could be introduced in the
circuit between the pump and the trachea. It is to be understood that, in these experiments,
the air passing into the animal's lungs was saturated with the vapour of the substance used
.
After artificial respiration had been set going, the heart was exposed by an incision in the