ACTION OF CHLOROFORM UPON THE HEART AND ARTERIES. 339 
by volume of absolute alcohol, is exemplified in fig. 22 (A and C). It will be observed 
that the effect of the addition of 1 part absolute alcohol to 9 parts chloroform is to largely 
prevent the fall of blood-pressure, which is recognised as being one of the most serious 
dangers attendant on chloroform inhalation, and at the same time to maintain the 
respirations at a force and frequency very little less than normal. The administration 
was made in both cases on the same animal by the same method, and using the same 
quantities of the solutions. 
It may also be observed how much more readily recovery takes place after removal 
of the mixed vapour than after removal of the chloroform. On the other hand, 
disappearance of the lid reflex occurs a little sooner when pure chloroform is used, but 
the difference is not great. | 
We have tried other proportions of alcohol and chloroform, but have obtained no 
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Fic. 24.—Administration by inhalation of air strongly charged with pure chloroform during 3 minutes to dog weighing 11 
kilog. which had received (13 hr. and 12 hr. previously) two doses of 00027 g. (x45 gr. in all) atropine sulphate. The vagus, 
tested immediately before this tracing was taken, gave no slowing and only a slight fall of pressure, even with coil at 0, 
Notice (1) the preliminary rise of blood-pressure due to excitation of vasomotor centre, succeeded by (2) a rapid and 
regular fall, less steep towards the end ; (8) entire absence of slowing of pulse ; (4) increase of rapidity, but decrease of 
excursion of respiratory movements, which became irregular, and eventually hardly perceptible. 
a, blood-pressure curve ; 6, respirations; c, time in 10 secs. ; d, signal of chloroformisation and abscissa of blood- 
pressure. The heart was still beating 4 minutes later, but the blood-pressure was at zero, and the respirations had wholly 
ceased. The animal was then subjected to artificial respiration by chest compression, and in 1 m. 40 secs. natural 
respirations were resumed, and the heart and blood-pressure rapidly recovered. The tracing shown in the next figure 
was taken prior to this one. 
better results. Indeed, with a 20 per cent. alcohol chloroform the respirations appeared 
to be more affected than with the 10 per cent. mixture. 
The beneficial effect can hardly be due to the mere dilution of the chloroform 
vapour by alcohol vapour; moreover, dilution with ether has not this effect, but 
the result is then practically the same as is obtained with undiluted chloroform. 
It is therefore to be ascribed directly to the beneficial action of the alcohol on the heart 
and respiratory centre. We are of opinion that a mixture containing one part by 
volume of absolute alcohol to nine parts of chloroform should be used when chloroform 
is indicated as the anesthetic, since these results show that it is far safer in its action 
than pure chloroform. There seems reason to believe that the greater safety of the 
A.C.E. mixture over chloroform depends upon the alcohol it contains, and that the ether 
is unnecessary ; it may further be noted that the alcohol in this mixture is in needlessly 
