328
The idea was that by certain combination of these several factors, the maximum quantity
of chloroform was absorbed by the blood in the lungs and hurried to the heart, the next organ
in the order of the circulation, not merely distending its cavities with chloroform-saturated
blood, but also being distributed by the coronary arteries to every part of its substance, and so
causing paralysis. This result is also assisted by the condition of distension of the heart and
the venous condition of the blood.
That the arrangement of these various factors—respiration, pulse, etc.,—has an im--
portant bearing in the action of the drug on the heart, is well shown by these experiments of
the Commission. These showed that by varying the methods of administration in different ex-
- p e r i m e n t s i t w a s p o s s i b l e t o m a k e t h e h e a r t c e a s e b e a t i n g a t i n t e r v a l s o f f r o m o n e t o t w e l v e
minutes after the cessation of the respiration. It is not impossible that by further variations
the time might have been reduced until the stoppage was simultaneous with, or even preceded
the cessation of respiration, and the experiments would have been thus made to accord with
certain reported fatal eases in man.
The cases in which the heart ceased soonest after the respiration were cases complicated
with asphyxia, that is, cases in winch semi-asphyxia was produced, presumably followed by
deep inspiration; under these circumstances the heart ceased beating one minute alter the res-
piration stopped. Now it is under conditions similar to these in man, that the so-called cardiac
syncope occurs, and it is by working on these lines that attempts to produce it in animals should
be made; but it appears that the Commission only made some four of these experiments hardly
a sufficient number upon which to base all important statement,
In ordinary practice, the several conditions giving a fatal result from cardiac syncope
are combined about once in every two or three thousand administrations. Because the Com-
mission did not obtain it in some 600 attempts they conclude that it cannot exist. This is
scarcely reasonable, especially as the bulk of their work was not upon the lines which promised
the nearest result, riz., those of deep inspiration after semi-asphyxia.
The manner or means by which the movement of the heart was tested are of some mo-
ment, as explaining the discrepancy between the results of experiment and practice.
Most of
the cases were tested by needle introduced into the heart, or by opening the chest. These
methods will indicate the merest quiver of the heart muscle.—movements that would give no
indication of their presence to ordinary observation, and movements that would probably be of
no funetional use,
i . e . , i n n o s e n s e c o n t r a c t i o n s .
I t h a s b e e n n o t i c e d b y o t h e r o b s e r v e r s , t h a t
the hearts of animals killed by chloroform show fibrillary after the heart muscle, as
a whole, is incapable of contraction,—a condition similar to this would indicate movement
tested by the above, but such movement would be fallaciou
s,
It would be interesting to know the degree of action exhibited by the heart after cessa-
tion of the respiration. Was the power of propelling blood retained? If the action consisted
only of muscular tremors it would be of little value, and hardly what is understood by action
of the heart.