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middle line, which was carried by a pair of blunt scissors or boneforceps through the ensiform
cartilage and lower part of the sternum. This was effected generally with no serious bleeding.
It soon became apparent that, when chloroform is given in this way, there is at once a most
serious effect on the heart; the right ventricle almost immediately begins to distend, the
heart presently stops, with the right ventricle engorged with blood. The heart has often, in
the case of rabbits, virtually come to a stand-still within a minute of the introduction of chlo-
-roform by the method described. The contrast was most striking when ether was used instead
of chloroform, the other steps in the experiment being the same. Ether may be given
for an indefinite period without interfering with the heart. We kept up artificial respiration
with ether in the circuit for an hour, not including twenty minutes occupied in producing
anæsthesia, and at the end of that time the exposed heart was beating as vigorously as at first."
It might be objected to those experiments that the dilatation of the heart, especially of
its right cavities, may be due to asphyxia, but the fact that the heart is not affected in the
same way by ether as by chloroform, although the other conditions of the experiment are
precisely similar, meets that objection.
(b) During the operation of registering the blood-pressure either by the mercurial or
by the spring kymograph, we observed in several instances, both in rabbits and in dogs, and
especially in dogs, even when the blood-pressure was not very low, a sudden failure of the
heart's action. This effect was a common occurrence during the administration of chloroform
especially in the earlier stages or when the animal was recovering; it rarely happened with
ethidene, and we never observed it with ether. This effect is well seen in the blood-pressure
tracings from the rabbit, G and H.* During deep narcosis, these sudden variations do not
occur. We were quite aware of the fact that those effects might be held to be duo to a
reflex mechanism, irritation of sensory nerves of the outer openings of the respiratory passages
stimulating the inhibitory centre of the vagi in the medulla, and thus retarding or even
arresting the action of the heart. Whatever may be the explanation, the fact remains that
at certain stages in chloroform narcosis there may be sudden falls in blood-pressure due to
interference with the heart's action, and no one will deny that this is a serious state of matters.
(c) We have seen in more than one instance the blood-pressure of the dog become enor-
mously reduced, and the pulsations become so infrequent as to be virtually ineffectual while
respiration continued. A record of this experiment produced the "Glasgow trace," as it is
termed by the Hyderabad Commission.† The explanation of this trace is of great importance,
and on this point we venture to differ from the Hyderabad Commission, as will appear
further on.
6. The principal points in which the Hyderabad Commission differ from us are (i) the
question of how death occurs under the administration of chloroform, whether the danger is
only of failure of the respiration, or whether there is danger also on the side of the heart;
*
Journal. Vol. II., 1 8 8 0 . p . 9 6 6 .
†
See Trace A, Journal, Vol, II., 1880, p. 962, which we have here reproduced.
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