Function of Red Corpuscles in Chloroform Ancesthesia. 567 



haemorrhage, is known to be a very slow process, and one dependent upon the 

 activity of the bone-marrow. The evidence which exists on this point, there- 

 fore, negatives the idea that any appreciable effect on the chlorine-content of 

 the blood can be due to this cause. 



3. Abnormal depth and frequency of respiration, combined with a high 

 percentage of chloroform, might conceivably cause abnormality in any set of 

 parallel experiments made before and after bleeding by the chloroform 

 entering the plasma to an excessive amount.* The possibility of this factor 

 coming into play necessitated a large number of experiments. 



Finally, the peculiar nature of the anaesthetic process, to which we have 

 drawn attention in another paper,t as an examination of the published 

 curves will at once make clear, renders it unlikely that any definite con- 

 clusions could be drawn from a small number of experiments as to the effect 

 produced by alteration in the volume of circulating blood. In the paper 

 referred to w T e showed that the percentage of chloroform in blood rapidly rises 

 to a point approaching a maximal value. When this point is reached, which 

 may occur within the first few minutes of an experiment, the animal often 

 ceases to breathe. This we have alluded to as the first danger-point of 

 anaesthesia. When this point is passed naturally, the chlorine-content of the 

 blood falls, but again rapidly rises. In most experiments, when breathing 

 stopped at this point, we found it better to allow the animal to resume 

 breathing and restart the experiment. In either case the maximal value was 

 quickly reached again, when an equilibrium occurred between the intake and 

 output of the drug. This state of equilibrium, when the percentage of 

 chloroform only rose very slowly, was often maintained for a considerable 

 period of time. During this period the respiration may stop at any moment 

 from slight causes which cannot be controlled. This further rendered it 

 necessary to make a large number of experiments. 



The operative procedures for the administration of chloroform and for 

 withdrawing blood were identical with those described in former papers. 



Experiments in ivhicli the Asphyxial State was rapidly reached. 



The percentage of chloroform used in these experiments was above 

 3 per cent, and under 5 per cent. Sometimes bags were used, sometimes 

 a WoulfFs bottle such as we have employed in experiments previously 

 described, so that a slight drag on the respiratory movements was produced. 

 These experiments may be fairly taken as representative of those in which 

 death occurred at the first danger-point of anaesthesia. 



* Buckmaster and Gardner, ibid. 

 t ' Roy. Soc. Proc./ this volume. 



2 s 2 



