ON ANAESTHETICS 159 
and such they found, as they believed, in ethidene dichloride, which they accord- 
ingly recommended as preferable to either of the others. But in order to ascer- 
tain the relative effects of the different substances upon the heart they used 
them all in a very concentrated form, the air being in many of the experiments 
made to bubble through the liquid contained in a Wolfe’s bottle on its way to 
a tube tied into the trachea; so that, to quote the words of the Committee, 
‘the air passed into the animal’s lungs was saturated with the vapour of the 
substance used.’ + Hence these experiments, though very interesting from the 
new facts which they elicited regarding ‘ ethidene’, and valuable as respects 
ether, by showing that it may be safely given, so far as the heart is concerned, 
in a very concentrated form, have really little bearing upon the use of chloroform 
in the human subject, where it is well understood that the agent must be given 
largely diluted with air. 
But these researches, by placing before the profession in an exaggerated 
form the effects of chloroform as a cardiac sedative, have tended to foster the 
idea that if chloroform kills, it always does so from the heart, and that the 
pulse is the main thing to be attended to in its administration. 
Against this pernicious error I have endeavoured in the earlier parts of 
this article to raise an emphatic protest. I have pointed out how liable 
the breathing is to become obstructed under chloroform, whether by the falling 
back of a relaxed tongue or by closure of the valve of mucous membrane which 
guards the orifice of the larynx ; and, further, how obstruction from either of 
these causes may occur without premonitory stertor, in an insidious manner 
requiring the utmost vigilance for its detection; so that, unless the attention 
is fixed upon the respiration, mere heaving of the chest and abdomen (which 
will continue long after air has ceased to enter the lungs), though doing nothing 
for the respiratory function, may be mistaken for effective breathing, the 
patient meanwhile being exposed to the serious dangers which attend a com- 
bination of asphyxia with the effects of chloroform. On the other hand, I have 
contended that if the breathing is carefully observed, and the obstructions 
referred to are removed as soon as they occur, due care being taken to avoid 
pushing the agent beyond what is needful to produce its anaesthetic and relaxing 
effects, the chloroform being given well mixed with the air by means of a folded 
towel held loosely over the face, all fear of primary failure of the heart may be 
dismissed from the mind. 
The experience of the last twelve years has confirmed me in the soundness 
of this doctrine ; and I venture to think it not undeserving of careful considera- 
tion that in my hospital cases I have still entrusted the administration of the 
? See ‘ Report on the Action of Anaesthetics,’ &c., Brit. Med. Journ., December 18, 1880, p. 957. 
