424 Messrs. G. A. Buckmaster and J. A. Gardner. [July 11, 



It was found more convenient to obtain the weight of the silver chloride in 

 this way, rather than directly by filtering through an already weighed 

 crucible, as it was almost impossible to prevent traces of glass dust getting 

 into the silver chloride during the heating and during the opening of the bomb. 

 This plan was, therefore, adopted in many of the experiments, but in any case 

 the result was always checked by dissolving out the silver chloride in the 

 manner described. We believe this plan far preferable in our case to that 

 usually followed of dissolving the silver chloride away from the glass and then 

 reprecipitating with nitric acid. 



Control Experiments. — In order to ascertain whether the percentage of 

 chlorine in the blood of an animal remains sufficiently constant during 

 prolonged anaesthesia accompanied by periodical bleeding, a number of 

 experiments were made with cats, which conclusively showed that under the 

 conditions of our experiments the percentage does remain constant. In 

 illustration we quote the following experiments : — 



Experiment 1. — A cat, weighing 3 - 2 kilogrammes, was anaesthetised by ether 

 and samples of the blood taken at intervals of ten minutes, the character of 

 the respirations being recorded on a drum. Every effort was made to keep 

 the anaesthetic condition of the animal as constant as possible during the 

 experiment. It was found that the colour of the blood afforded a good index 

 of the degree of the anaesthesia. Six samples of blood were taken, after which 

 chloroform was administered until the animal was asphyxiated, when a seventh 

 sample was taken. The results of the analysis are given in the following 

 table — Table I. The colour of the blood after respiration ceased was a deep 

 brownish-red, such as we have always found to be the case in chloroform 

 narcosis at this stage, though the oxygen-carrying property of haemoglobin 

 is known not to be impaired by chloroform. 



Experiment 2a. — A pregnant cat, weighing 3 3 kilogrammes, was anaesthetised 

 as before, and samples of blood taken. The experiment was somewhat similar 

 to No. 1, except that the intervals between the abstraction of the various 

 samples were longer. Five samples were taken, after which chloroform was 

 administered until the animal was very deeply under the influence of the 

 drug, but was still breathing satisfactorily. 



The results are given in Table IIa. 



Experiment 2b. — A cat, weighing 2'5 kilogrammes, was etherised. Four 

 samples of blood were collected for analysis, but between the first and second 

 samples 10 c.c. of blood were withdrawn, and between the third and fourth 

 5 c.c. After the fourth sample was taken the animal was chloroformed, using 

 a Woulff's bottle, until respiration ceased. 



The results are given in Table IIb. 



