414 



The Ancesthetic and Lethal Quantity of Chloroform in the Blood 



of Animals. 



By G. A. Buckmaster, Assistant Professor of Physiology, University 

 College, University of London ; and J. A. Gardner, Lecturer on 

 Physiological Chemistry, University of London. 



(Communicated by Dr. A. D. Waller, F.E.S. Received July 11, — Eead 

 November 1, 1906.) 



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



Observations made in vitro on the relations which exist when liquid 

 chloroform and defibrinated blood are in contact have shown that with 

 equal concentrations of chloroform the tension of this in blood, serum or 

 solutions of haemoglobin, is very much lower than in water or saline 

 solutions ; a definite quantity of chloroform is associated with some con- 

 stituent or constituents of the blood. When known weights of chloroform 

 and blood are mixed together at 37° C, a percentage of 1*5 or more produces 

 a precipitate of haemoglobin. Determinations of the quantity of chloroform 

 held by defibrinated blood have shown that for a given weight of chloroform 

 this amount cannot be recovered by any of the methods which have been 

 employed. The deficit may range from 2 to 20 per cent. We are of opinion 

 that no experiment made in vitro can be regarded as an indication of what 

 obtains when chloroform vapour is inhaled. The normal physiological 

 conditions are not reproduced even when the vapour is in contact with 

 defibrinated blood, which is apparently not the mode in which the majority 

 of the experiments with which we are acquainted have been conducted, and 

 still less are physiological conditions preserved when liquid chloroform is 

 shaken up with blood. 



Our observations were commenced in October, 1905, and carried out in the 

 Physiological Laboratory of the University of London. We have employed 

 an entirely new method of chloroform determination applied to the blood of 

 anaesthetised animals — large cats were used for the majority of the experi- 

 ments since the phenomena of anaesthesia in these animals closely resemble 

 those in man (Mac William)* — and shall only refer briefly to the methods 

 and results of those observers who have carried out such determinations of 

 the quantity of chloroform found in the blood, with anaesthetic and lethal 

 doses of this drug, as can be fairly compared with the results we have 

 obtained. 



* 'Bril. Med. Journ.,' 1902. • 



