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The Pharmacology of Ethyl Chloride. 

 By E. H. Embley, M.D., Hon. Anaesthetist to the Melbourne Hospital. 



(Communicated by Dr. C. J. Martin, F.E.S. Eeceived June 13, — Read June 28, 



1906.) 



(From the Physiological Laboratory of the University of Melbourne.) 



The rapidity with which ethyl chloride has established its claims as 

 a general anaesthetic for short operations appears justified by the advantages 

 which its employment offers. It induces anaesthesia pleasantly and very 

 rapidly, and compares favourably with nitrous oxide in these respects. The 

 rapidity with which anaesthesia is induced, and the comparatively prompt 

 recovery upon cessation of the administration, combined with the relatively 

 small degree of vomiting or nausea, are its great advantages over ether and 

 chloroform. The greater duration of anaesthesia following upon cessation 

 of administration together with its portability are its advantages over nitrous 

 oxide. Its position, therefore, in the armamentarium of the anaesthetist is 

 that of filling the important gap between the light and brief anaesthesia of 

 nitrous oxide and the deep narcosis of chloroform or ether. 



This position is held, however, not without disabilities. In the first place 

 muscular relaxation is not often completely attained until a deep degree of 

 narcosis is reached and, more important by far, it is not as safe as nitrous 

 oxide. The death rate . is much greater than that of nitrous oxide and 

 according to McCardie (1), is as high as 1 in 3000. 



Ethyl chloride was first used as a general anaesthetic in 1848 by 

 Heyfelder. Benjamin Ward Richardson experimented with it in 1867 and 

 it was the subject of an enquiry by a Committee of the British Medical 

 Association in 1880, who reported unfavourably upon its employment as 

 a general anaesthetic. The revival of ethyl chloride as an anaesthetic for 

 short periods occurred in 1895 — 6 and an historical account of its 

 re-introduction will be found in a paper, "Ethyl Chloride as a General 

 Anaesthetic," by W. J. McCardie (2). According to McCardie some experi- 

 mental observations upon its pharmacological action have been made by 

 Wood and Cerna, Koenig, Malherbes, and Roubinovitch, but I regret that 

 the literature has not been available, and I have been unable to consult 

 these papers. 



The physiological action of a commercial preparation containing ethyl 

 chloride 65 per cent., methyl chloride 30 per cent., and ethyl bromide 

 vol. lxxviii. — b. 2 H 



