ON ANASSTHETICS. 311 
Milligrammes of CHCl; per 100 grammes 
ood, 
of bl 
Chloroform adminis- 45 min. 2 hr. 
tration stopped. later. later. 
Arterial blood oH ies 53°2 58 0 
Venous blood mas ves 48-1 77 4°9 
In our own experiments, immediately the inhalation of chloroform 
stopped a sample of blood was taken from an artery, and this was 
repeated at intervals, until half or three-quarters of an hour had 
elapsed. In other experiments venous blood taken close to the right 
ventricle of the heart was examined in the same way, while in a few 
experiments samples of arterial and venous blood were taken simul- 
taneously. The main conclusion which can be drawn from these 
experiments is that the rate of elimination of the drug from the body 
vid the blood depends upon the physiological state of the individual 
animal. The rate of loss is at first comparatively rapid, and subse- 
quently becomes slower. But the initial rates of elimination are much 
less rapid than the initial rates of the intake of chloroform, and, on the 
whole, elimination is a much slower process than assumption, a view 
which is supported, not only by the actual determinations of chloroform 
in the blood, but by a comparison of the times at which the various 
reflexes disappear and reappear. From our curves the initial falls are 
not quite so rapid as the work of other observers had led us to suppose. 
60 
50 
40 
30 
20 
10 
Amount of OHCl, in milligrammes per 100 grammes, 
Smins. 10 15 20 
Plotted curve of the amount of chloroform in the blood (arterial) of a cat during recovery irom deep 
anesthesia. (Proc. Roy. Soc., vol. xxix. p. 585.) 
The chloroform-content of the blood was only reduced by 50 per cent. 
in fifteen to twenty minutes; three-quarters of the chloroform was 
eliminated in about half-an-hour. These statements hold good when 
the animal is breathing naturally, but, as might have been expected, 
the extent to which the lung is being ventilated during any period is the 
chief, if not the only, factor which determines the rate of elimination. 
Our experiments are in agreement with Tissot’s observations: that at 
the moment when chloroform inhalation stops arterial blood contains 
an excess of the drug when compared with venous blood, but the differ- 
ence between the amount of chloroform in arterial and venous blood 
after regular respiration is established is practically the same. . 
