1902.] Regulation of the Administration of Chloroform. 505 



The outlet of box I is connected, by an arched tube joining the stop- 

 cocks, with the inlet of box II. Air is drawn in at the inlet of box I, 

 and air and chloroform are drawn out from the outlet of box II. The 

 first box is charged about half-full with a mixture of chloroform and 

 alcohol, the second with water, about 2 J litres in each. The two boxes 

 stand in a shallow tank, and are immersed in water of which the 

 temperature can easily be kept constant. The second box, with its 

 charge of water, is for the purpose of absorbing alcohol vapour. 

 When the mixture of air with the vapours of chloroform and alcohol 

 has passed slowly for several hours, the water takes up no more 

 chloroform ; but the absorption of alcohol vapour continues almost 

 indefinitely. 



By varying the proportion of chloroform to alcohol and the tempera- 

 ture of the mixture, the proportion of chloroform to air in the gas 

 drawn through may be varied from a large percentage to a small 

 fraction per cent. If the apparatus is on a sufficient scale relatively 

 to the maximum volume of gas drawn through in unit time, the rate 

 of passage of the gas will not affect the composition of the mixture, 

 saturation under the actual conditions having been attained. 



The following experiments were made to test the fulfilment of the 

 last-named condition of constancy : — 



(1.) Air was drawn from the boxes through a flask for a quarter of 

 an hour at the rate of 400 c.c. per minute. The contents of the flask 

 were then analysed; percentage of chloroform, 1*45. 



(2.) Air drawn through for 8 minutes at the rate of 4000 c.c. per 

 minute; percentage of chloroform, T42. 



(3.) Eepetition of (1). Passage of air and chloroform at 400 c.c. 

 per minute, continued for half an hour. Percentage of chloroform 

 1-47. 



The temperature of the water in the tank was throughout 9° C. 



The difference in the proportion of chloroform when air is passed 

 through at 400 and at 4000 c.c. per minute is too small to be material. 

 Hence, in the apparatus employed, the length of travel of the air over 

 the surface of the liquid is sufficient for the vapour of chloroform to 

 have attained at the greatest rate of passage, being that of ordinary 

 respiration, its maximum tension at the actual temperature and partial 

 pressure upon the surface of the liquid. 



The method used for estimating chloroform is that in which a flask 

 having a capacity of 800 or 900 c.c, of which the interior has been 

 wetted with a few c.c. of water, is charged with the mixture of air and 

 chloroform (fig. 3). There is then brought into it a spiral of fine plati- 

 num wire, through which an electric current can be passed. The water 

 at the bottom of the flask is heated to between 50° and 60°, and the wire 

 is rendered incandescent. A cloud of hydrochloric acid appears, which 

 dissolves in the water. In 20 minutes the change is complete. The 



