i879*] 
Safe Ancesthesia. 
1 77 
Dr. McKendrick, Professor of Physiology in the University 
of Glasgow, have already issued two reports, abstracts of 
which we propose to lay before our readers : — 
In studying the question of the effedts of chloroform on 
the respiration and the heart, it soon became apparent to the 
committee that chloroform administered to dogs and rabbits 
has a disastrous effedt on the respiratory centres ; it is easy 
to kill one of these animals by pushing the chloroform till 
respiration is paralysed. In observing the state of the heart 
during these experiments, it could often be determined by 
auscultation that its contractions were maintained after re- 
spiration had ceased. It was apparent, however, that, even 
when failure of respiration was more directly the cause of 
death, the heart was to some extent simultaneously affected ; 
and there were even cases in which the heart appeared to 
fail at least as soon as, if not before, the breathing. Con- 
sidering these facts, and bearing in mind that failure of the 
heart is often asserted in the reports of death from chloro- 
form, a method of experimentation was devised by which 
respiration would be eliminated, and the effects of chloroform 
on the heart observed apart from that complication. 
In the frog the movements of respiration are not necessary 
to life, so far as the heart is concerned, as that organ con- 
tinues beating long after these movements have ceased. 
After exposing this animal to the vapour of chloroform under 
an inverted jar until it was anaesthetised, it was found that 
the heart became rapidly weaker, till it ceased beating, but 
with ether the heart continued vigorously beating as long as 
the experiment was continued. 
A method was now devised for warm-blooded animals, 
such as rabbits and dogs. It was found that chloroform 
immediately produces a serious effedt on the heart ; the right 
ventricle almost immediately begins to distend, and the heart 
presently stops with the right ventricle engorged with blood. 
In the case of rabbits the heart often virtually came to a 
standstill within a minute of the introduction of chloroform. 
Ether may, however, be given under the same conditions for 
an indefinite period without interfering with the heart. 
Artificial respiration with ether was maintained in the circuit 
for an hour, and at the end of that time the heart was beat- 
ing as vigorously as at first. 
In this respedt, therefore, ether possesses an enormous 
advantage over chloroform, but ether has the great disadvan- 
tage of tardiness of adtion. In comparative experiments 
with rabbits, in which the anaesthetics were given on a towel, 
it appeared that with chloroform complete ansesthesia was 
VOL, IX. (N.S.) N 
