ON ANESTHETICS. 155 



the past six months, principally in the hands of Mr. G. E. Phillips, 

 the resident anaesthetist, whose report is contained in Appendix III., 

 and under the frequent observation of Sir Frederic Hewitt, Dr. 

 Blumfeld, and Dr. Waller. 



This Committee desire to tender their sincere thanks to the House 

 Committee of St. George's Hospital for their liberal co-operation. 



In the laboratory our knowledge has been augmented by the inde- 

 pendent work of Dr. Buckmaster and Mr. Gardner, who have through- 

 out the year accumulated a large mass of valuable data concerning the 

 composition of the blood-gases in chloroform anaesthesia in the physio- 

 logical laboratory of the University of London. Their full paper has 

 been published in the ' Journal of Physiology ' of March 1911. 



A further paper on the ventilation of the lung during chloroform- 

 narcosis, of which the account must be deferred, has been commu- 

 nicated to the Royal Society during the present month [November 

 1911]. 



APPENDIX I. 



The Installation of a Chloroform-balance in Hospital for Ordinary Daily 

 Use. By A. D. Waller, M.D., F.R.S. 



The principle upon which the apparatus is based has been described 

 in several publications, most fully so in the fifth Hitchcock Lecture pub- 

 lished last year. 1 It will be sufficient in preface to the present descrip- 

 tion of the apparatus as set up for practical purposes at St. George's 

 Hospital to state that the object to be fulfilled is the delivery at a 

 face-piece of a sufficient volume of chloroform-and-air of known and 

 easily controlled percentage. 



The essential parts of the apparatus are : — 



1. The chloroform-balance, 



2. The chloroform flask, 



3. A mechanical blower, and 



4. Tubing from the blower to the flask and balance, and from 



the balance to the face-piece or mask. 



Graduation of the Chloroform Balance. 



The chloroform-balance consists of an ordinary enclosed balance 

 with the scale-pans replaced by a closed-glass bulb of a capacity 

 between 500 and 1,000 c.c. and a brass counterpoise. The bulb rises 

 and falls according as the density of atmosphere in the balance-case 

 is raised and lowered by chloroform vapour driven into the case from 

 the chloroform flask. The sensitiveness and range of movement of the 

 beam are such that the deflections of the index embrace a range of at 

 least 3 per cent, of chloroform-vapour present. The graduation of the 

 scale behind the index is determined by the weight of chloroform- 

 vapour per 100 in relation to the capacity of bulb used, taking the 

 litre-weight difference between chloroform-vapour and air = 4"045 

 grammes at 0° and 760 mm. Hg. Thus for a bulb of 1,000 c.c. the 

 weights corresponding to 1, 2, and 3 per cent, are 38, 76, and 114 



1 Physiology the Servant of Medicine, : Chloroform in the Laboratory and in 

 the Hospital. The University of London Press, 1910. 



