PHYSIOLOGY. 
275 
deep irregular respirations and at last three or four convulsions, 
followed by death. If one stops quick enough the tracheal in¬ 
halation, the accident disappears, the respiration being re-estab¬ 
lished. 
In administering ether in the same condition, the production 
of so alarming symptoms does not take place. The first inhala¬ 
tion may last four or five minutes without producing the slowing 
or stopping of the heart. The respiration is also less disturbed. 
In resum6, the introduction of anaesthetic vapor into the circula¬ 
tion is accompanied—with chloroform, by acceleration of the 
heart, suddenly followed by lowering in action and stopping of 
this organ (sideration). With ether—by acceleration and a sim¬ 
ple weakening of the contraction of the heart. 
The second period of excitation is observed after the section of 
the par vagum nerves, proof that the explanation given is not ac¬ 
ceptable. In combining this section with those of the spinal 
marrow, one may convince himself that the acceleration of the 
heart and the increase of the arterial tension are placed under the 
influence of the bulbo-medullary centers and of the sympathetic, 
and the stopping of the heart under the dependence of the par 
vagum. 
2d. If, stopping and continuing at times the tracheal inhalation, 
one continues the administration of the anaesthetic until the appari¬ 
tion of the toxic phenomena, one with astonishment will 
observe that the animals present a kind of accoutumance, a moment 
arrives when the inhalations must be continued to bring on death. 
In this case the chloroform produces an increasing acceleration of 
the heart, in spite of which, the arterial pressure diminishes more 
and more, because the length of the systole becomes less and less ; 
soon the pulsations, separated by long intervals, become rare and 
soon difficult to feel; at last the heart stops, two or three minutes 
after the respiration. This function offers, before it stops, 
phases of acceleration and of apncea; at times it diminishes in ampli¬ 
tude to such extent that its tracing resembles the graphic of 
rapid arterial pulsations. The intoxication by ether has a 
special physiognomy. The heart stops, and then after the res¬ 
piration, beats faster and faster. The pulsations are small, 
