324 PROFESSOR E. A. SCHAFER AND DR H. J. SCHARLIEB ON THE 
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Fic. 10.—Testing of cardiac centre by stimulation of central end of 
one vagus—the other being intact—in the dog from which 
the tracing given in fig. 9 was taken, and immediately 
previous to that tracing. 
a, b, c,d, e, f as before, Notice, as with chloroform, the 
great diminution in force of the auricular beats, but without 
arrest or slowing, the diminution in force of the ventricular 
beats being hardly perceptible. The fall in blood-pressure 
may be in part due to depressor action, but a similar fall 
was obtained by stimulation of the peripheral cut vagus, 
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Fic, 11.—Chloroform inhalation. Showing cessa- 
tion of auricle before ventricle, the latter then 
assuming its independent rhythm, with larger 
excursions, 
a, auricle ; b, ventricle; c, blood-pressure 
(the alignment of this pen is a little in ad- 
vance of the others); c!, zero of blood-pressure ; 
d, time in 10 seconds. Artificial respiration 
by perflation. 
Fic. 12,—Effect of excitation (with coil 100) of the peripheral vagus (second signal) during moderately deep chloroform 
anesthesia, strong chloroform vapour having just previously been administered during 14 minutes (first signal). - The 
result is seen to be an immediate heart arrest, with the blood-pressure falling to zero ; the respirations cease 30 seconds after 
the heart has stopped, but are only gradually arrested. In this case the heart (ventricle ?) begins to escape from the arrest 
renewed. 
after 40 seconds, beating at first very slowly, but after a minute faster: as the heart recovers, the respirations are also : 
! 
