ON ANASSTHETICS. 803 
penalty often has to be paid, so to speak, for this rapid induction—viz., 
some disturbance in the smoothness of the subsequent anesthesia. 
Although the method here advocated has the disadvantage of a com- 
paratively lengthy induction, the eventual type of anesthesia is highly 
satisfactory. In a word, we have no hesitation in recommending this 
mixture, administered by means of the particular mask and method we 
have described, as one which is capable of a wider range of applicability 
in general surgery than any other anesthetic or mixture with which we 
are acquainted. Whilst the anesthetic we have attempted to describe is 
undoubtedly safer than that produced by sprinkling undiluted chloroform 
upon lint, towel, or any form of open inhaler;we do not contend that 
it is safer, whilst the patient is wpon the operating table, than ether 
anesthesia. If, however, we take into account the risks of ether anes- 
thesia after the operation, we are of opinion that the method compares 
favourably with all known methods of etherisation, so far as safety is 
concerned. 
APPENDIX II. 
Descriplion of the Chloroform Balance. By Dr. A. D. Wautmr, F.R.S. 
A closed glass bulb (capacity=870 c.c.) is suspended from one 
side of the beam of an ordinary balance, the pointer of which shows 
3 millimetres per centigramme, and is counterpoised at the other side 
of the beam. 
The balance case (capacity =about 30 litres) is provided with inlet 
and outlet tubes, the former connected with a chloroform bottle through 
which a current of air (in this case about 15 litres per minute) is 
established by a pump or bellows, the latter connected with the mask 
or tube by which the mixture is delivered. The tube from the bellows 
or pump is provided with an elastic bag, and a constant stream of air 
of known volume per minute (10 to 20 litres) is secured by a perforated 
“ stop ’ fixed in the lumen of the tube; the chloroform bottle is provided 
with a regulating tap, by which all or none of the stream of air is passed 
through the chloroform bottle at will. The latter is graduated. 
The percentage of chloroform (or of ether vapour if ether be used) 
is indicated by the pointer of the balance. It is at the same time 
-recorded, if desired, on the smoked surface of a drum revolving once 
per hour (or per 12 hours), by means of a light pen fixed to the beam of 
the balance. This pen serves at the same time to damp the oscillations 
of the beam. 
The calibration of ? of the instrument is effected by means of weights 
corresponding to the weights of 1, 2, 3 per 100 of chloroform vapour 
in the volume of air represented by the bulb at ordinary temperature 
and pressure. 
The zero of the chloroform scale is given by the position of the 
1 For the calibration at 18° C. and 760 mm. Hg of a chloroform balance in relation 
to the volume of a given bulb, divide the volume in c.cms. by 26 35; the quotient 
expresses the number of milligrammes that correspond to 1 per cent. of chloroform 
vapour, e.g., for a bulb of 870 c.c. the corresponding weight is 870 : 26°35 or 33 milli- 
grammes, and the scale of 1 to 3 per cent. is given by weights of 33, 66, 99 mgms. 
The effect of variations of temperature and pressure may be disregarded in this 
connection. The corrected values of 1 per cent. would be 1:017 and 0983 at 28° 
and 13° res; ectively (i.e., at 74° 4 and 56°°4 F.). 
