309 



The Estimation of Chloroform in the Blood of Ancesthetised 



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 February 1, — Eead 



February 21, 1907.) 



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



In a former paper* we expressed doubt whether the methods employed by 

 Dr. Maurice Mcloux and other French observers for accurately determining 

 the percentage of chloroform in the blood of ancesthetised animals were 

 capable of yielding such satisfactory results as those obtained by Mcloux 

 when known quantities of chloroform were added to blood in vitro; 

 on the ground that the mixing of blood and chloroform in vitro is an 

 essentially different process from that which takes place during the 

 physiological process of inhalation, since it has been shown that, daring 

 anaesthesia, chloroform associates itself particularly with the red corpuscles. 



In order to test the validity of our criticism, and to enable the results 

 obtained by the French observers to be correlated with our own, and also to 

 gain an idea as to how far the method employed by Mcloux is capable of 

 giving reliable results in the case of tissues to which our method may not be 

 readily applicable, we have made a series of parallel estimations by the two 

 methods on the blood of anaesthetised animals. 



In our experiments with the method of Mcloux, we followed closely the 

 procedure which he has detailedf, and we take this opportunity to express 

 our indebtedness to Dr. Mcloux for his kindness in supplying us with the 

 distillation-apparatus which he uses, and in giving us a demonstration of his 

 method. As Mcloux points out,J the chief difficulty in his method consists 

 in determining exactly the end-point of the reaction which occurs in 

 titrating with silver nitrate, using potassium chromate as an indicator. 

 While taking every care to hit the end-point as closely as possible, we 

 uniformly slightly over-stepped rather than under-stepped the mark. In 

 carrying out the method, we found it necessary to use caustic soda made 



* ' Roy. Soc. Proc.,' B, vol. 78, p. 418, 1906. 



t " Dosage de petites quantites de chloroforme," ' Extraits du Bulletin de la Soci6t6 

 Chimique de Paris,' 3rd series, vol. 33, p. 321, 1906. 



X ibid. 



