1902.] Regulation of the Administration of Chloroform.. 507 



end enter the mixture of chloroform and air, and also water falling into 

 a lateral tube at the rate of about one drop a second. The slow trickle 

 of water along the bottom of the tube is heated by the wire above it, 

 and thus furnishes the necessary supply of steam, while serving also 

 to dissolve the hydrogen chloride, and carry it into the flask beneath. 



Fig. 5. Fig. 6. 



A full account of these methods of testing with the record of the 

 experiments by which their trustworthiness has been established, will 

 probably appear in the ' Journal of the British Medical Association,' 

 for a Committee of which body the second method has been planned 

 and used. 



By the first method it has been found that to obtain a mixture of 

 98 per cent, air and 2 per cent, chloroform, which suffices to produce 

 full ansesthesia, the box should be charged with a mixture of 80 per 

 cent, alcohol and 20 per cent, chloroform and kept at a temperature 

 of 15°. With this mixture, and at this temperature, however slow an 

 inspiration may be, the proportion of chloroform to air cannot rise 

 above the comparatively safe limit of 2 per cent. 



To reduce the dose of chloroform below 2 per cent, a three-way stop- 

 cock has been made giving always free passage to air, but admitting at 

 one end of its range air with the full charge of 2 per cent, of chloro- 

 form, at the other end air only. Between the two is a graduated arc 

 over which a pointer moves, the divisions on which give approxi- 

 mately the percentage of chloroform in the air which is being inhaled. 

 The long handle of the stopcock which forms the pointer is easily 

 moved by the pressure of the finger. 



At the outlet of the stopcock are two valves, opening and closing 

 with each inspiration and expiration respectively. Between the two 

 valves is a short tube connected by a piece of flexible tubing with a 

 face-piece of the usual type (fig. 7). 



