CHLOROFORM IN USE 567 



It is possible, however, to make an approximate comparison 

 between cases anaesthetised by the open method and the present 

 series. It was found that the time of induction by both methods 

 was about the same. It follows that approximately the same 

 percentage must have been given, but the individual variations 

 were very much greater with the open method, and depended 

 more on the anaesthetist. The results of the skilled professional 

 were very like the curves just given ; while in those of the com- 

 parative beginner one would judge that the percentage at the 

 beginning was greater than the optimum, and, later on, rather 

 less. 



One curious result sometimes occurs with the open method. 

 Although at least 4 per cent, can be obtained from a cone of 

 lint (see fig. 8 later), sometimes the anaesthetist complains that, 

 do what he will, the patient will not remain completely relaxed. 

 It is customary to lay the blame on the particular brand of 

 chloroform employed, but, as every brand is accused in turn, 

 and as this difficulty is not found with the machine, it is 

 probable that some other explanation must be sought. 



In some of the forty cases the operation was prolonged for 

 a considerable time. It is interesting to note how that, for a 

 very long period, the patient can be kept at a perfectly even 

 degree of anaesthesia with the same percentage of chloroform. 

 This evenness appears to depend on two factors, the first being 

 the steady percentage of chloroform, and the second the nature 

 of the operation. If the first factor is kept constant it is possible 

 to study the second, and a very curious observation was made 

 on a point which is of some importance. A patient is at the 

 even stage of anaesthesia just described, and the corneal reflex 

 is just absent. Now, if any violent afferent impulse is set up 

 (if, for instance, the parietal peritoneum is pulled to allow of 

 the sutures in it being tied), the patient becomes less deeply 

 anaesthetised, the respiration increases in depth and frequency, 

 the blood-pressure falls, and the corneal reflex comes back. 

 The analogy is very close to the condition seen in morphia 

 poisoning, where the subject can be aroused by shaking or 

 other measures, to fall back again into unconsciousness when 



individual variation. From the considerations mentioned above it follows that it 

 is not possible, even in these cases, to say that each patient retained the same 

 amount when breathing in 2 per cent, vapour, and so the dose cannot be calculated 

 exactly. 



