555 



The Rate of the Assumption of Chloroform by the Blood during 



Ancesthesia. 



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.R.S. Eeceived March 7, — Kead 



April 18, 1907.) 



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



Although it is obvious that the essential condition of anaesthesia is one in 

 which chloroform is associated with the cells of the body, and among these 

 the cells of the central nervous system, the gradual storing-up of the drug 

 must depend upon the supply available in the blood, the red corpuscles of 

 which are, as we have shown, the chief agents for the transport of chloroform 

 either from or to the pulmonary alveoli. 



A definite threshold-value for the percentage of chloroform in arterial 

 blood must be reached in order that anaesthesia shall occur, and the state be 

 maintained. The drug, as Tissot, Nicloux, and ourselves have found, 

 is eliminated at first rapidly, and subsequently more slowly, on the cessation 

 of the administration of chloroform. During anaesthesia the drug does not 

 simply accumulate, since the processes of intake and output go on side by 

 side. Though chloroform is eliminated at first with great rapidity, the last 

 traces of the drug take a long time to slowly leak out of the tissues, but 

 apart from this fact the elimination of a high percentage of chloroform in the 

 blood takes place nearly as rapidly, and perhaps at times even as rapidly, as 

 the assumption of a high percentage. 



The following scheme probably represents what occurs during anaes- 

 thesia : — 



B. Portion which 



does not reach the 



alveoli, but is expired. 



A. Mixture of chloro- 

 form vapour and air, 

 constantly supplied in 

 excess. 



C D. Portion which is 

 1 associated by the 



< 



C. Portion which tissues. 



reaches the alveoli and^ . . . 



,, , , , E. Portion which is 



enters the blood. . 



eliminated at the pul- 

 monary epithelium. 



The relative amounts of B and C will, for a given percentage of chloro- 

 form, depend upon the rate and depth of the respiratory movements. This 



