320 PROFESSOR E. A. SCHAFER AND DR H. J. SCHARLIEB ON THE 
brief rise of pressure at the beginning of an experiment is sufficiently manifest, and in 
others again there is apparent, even when the respirations are maintained, a rise towards 
the end of the experiment. Since in these cases asphyxia is eliminated, and the heart 
is probably not beating more but less strongly, such a subterminal rise can only be 
ascribed to the excitatory action of the drug upon the vasomotor centre, or directly upon 
the arterioles. It is exemplified in fig. 5, which shows the tracing from the latter half 
of an acute chloroform poisoning, terminating by a slowing and arrest of the respirations, 
followed after a few seconds, suddenly, by complete arrest of the heart. In this tracing 
it will be observed that long before the failure of the respiration begins to show itself 
there is a decided tendency to rise on the part of the arterial pressure, although the 
heart at this time is not beating more but rather less strongly (the increase in size of 
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Fic. 6.—Tracing (dog) showing marked secondary rise of blood-pressure during chloroform inhalation, probably due to early 
failure of respiration. The chloroform was administered between the two marks on the signal line. Notice the cardiac 
inhibition, which in this case is more gradually developed than usual, and the subsequent escape of the ventricle, which 
continued to beat feebly for a minute or two, but with hardly any rise of blood-pressure. Artificial respiration by pump 
commenced 10 minutes after natural respiration had ceased, failed to effect recovery. 
a, blood-pressure ; b, tracing from needle passed through chest wall into ventricle; c, thoracic movements ; d, dia- 
phragmatic respirations ; ¢, time in 10 seconds; f, signal. The horizontal line at b is 10 mm. below the abscissa of blood- 
pressure. 
the arterial pulsations seen near the end is a result of slowing of the cardiac rhythm). 
This rise of pressure therefore must be due to arterial constriction caused by the drug. 
The chloroform was given as concentrated vapour, producing abolition of corneal reflex 
in one minute and death in about four minutes; but how far the constriction was due to 
direct action upon the arterioles, and how far to an action upon the vasomotor centre, 
the experiment does not determine. The continuation of the rise in the tracing may 
perhaps be ascribed to a condition produced by the commencing failure of respiration, the 
vasomotor centre being stimulated by the venous blood; especially as it is accompanied 
by a certain amount of cardiac inhibition. Such asphyxial rise may be very marked 
