THE PRICE OF ANESTHESIA 615 



be administered with plenty of air, but that it was practically 

 very difficult if not impossible to secure the administration of 

 the vapour between an}'- definite limits of percentage. 



This opinion was, I think, in the main correct. Snow's 

 inhaler, in which the patient inspired through a bottle con- 

 taining liquid chloroform, had been found to be not free from 

 danger, the estimated percentage was rather high (4 per cent, 

 or 5 per cent.) and the apparatus fell into disuse until recently,, 

 when it was revived under a slightly different form by Vernon- 

 Harcourt, and favourably reported on by a committee of the 

 British Medical Association.^ The percentage of delivery of 

 this modified form is adjusted to be from o'5 to 2 per cent., 

 but in my opinion the percentage scale with which the instru- 

 ment is furnished is no real indication of the actual percentage 

 of delivery. The method is the everyday method of the 

 laboratory, where prompt rather than safe anaesthesia is 

 required ; but obtained at a price of accidental deaths by over- 

 doses with which every physiologist is familiar. 



Paul Bert's method to deliver to the patient chloroform and 

 air at known percentage from a large gasometer proved to be 

 quite impracticable. 



Another French apparatus, that of Raphael Dubois, has 

 fallen out of use in France, and has been condemned in this 

 country as being cumbrous and expensive. It is, as I have 

 elsewhere stated/ a very safe apparatus indeed, and my opinion 

 has been confirmed during the last three years by the far more 

 extensive experience of Dr. Paul Chapman, of Hereford. I 

 believe, however, that the method is inferior both in certainty 

 and in convenience to that which I shall finally describe. 



An apparatus of my own,^ called the wick-vaporiser, based 

 on the principle of the carburettor of a motor-car, and adjusted 

 to deliver by the evaporation of chloroform from i, 2, or 3 wicks, 

 I, 2, or 3 per cent, of chloroform vapour, has rendered good 

 service in the laboratory, has proved satisfactory in a limited 

 number of trials in hospital, but is open to an objection that 

 applies in more or less degree to all other forms of apparatus 



^ Brii. Med. Joiirn., July 1903. 



* "An Examination of Apparatus proposed for the Quantitative Administration 

 of Chloroform," Lancet., July 9, 1904. 



3 " The Wick- Vaporiser," Proceedings of the Physiological Society, August 19,, 

 1904 ; Journal of Physiology., vol. xxxi. 



