igoo-i.l Observations on Blood Pressure. 201 



are the advantages claimed for this preparation^" My experiments 

 were done through the several Canadian seasons upon many varieties of 

 dogs, and yet I never found the heart stop before the respiration, 

 although, as stated, on several occasions the pulse tracing did so. Dr. 

 B. W. Richardson in my opinion stated the case aright when he wrote 

 that " death in man during chloroform anesthesia is not generally due 

 to respiratory failure, but that in animals the physiological death from 

 chloroform is a respiratory failure."' He says that Snow also thought so. 



In my experiments the animals were killed with chloroform in the 

 horizontal and vertical postures, after poisoning with various drugs, 

 cutting of one or both vagi nerves, division of the spinal cord at various 

 levels, opening of the abdomen, bleeding, etc., and yet, as stated, the 

 respiration always stopped before the heart. 



Post mortem examinations were made on most of the animals 

 so killed, but the condition of the heart and great vessels then 

 does not seem to be any indication of what it was just after 

 death, as artificial respiration, abdominal pressure and other restora- 

 tives were all tried, and these must have altered the conditions 

 of things. Such remarks may also apply to the results of post 

 mortems on persons who have so died. With this proviso, one may 

 say that the right side of the heart was always engorged with blood, and 

 that the left was generally more or less empty, but occasionally also was 

 full. In one case after death from chloroform, followed by artificial 

 respiration, the animal's body was frozen, and transverse sections of the 

 chest made. Here the right side of the heart was found to be engorged 

 and the left was partially filled with blood.^' 



The most dangerous time for a dog is while he is going under first. 

 Then, if he be struggling, the danger is great. In most cases, as already 

 stated, when the breathing had stopped under these circumstances, 

 artificial respiration would restore it and save life, but occasionally it 

 failed to do so. 



When chloroform is given slowly and sufficiently diluted then 

 the animal goes under completely without necessarily much, if any, 

 fall in blood pressure. This is in agreement with Shore and Gaskell's 

 results.* The least struggle, however, even if only of the nature of 

 increased respiration, temporarily sends up the blood pressure more or 



1 Philadelphi.T Medical Journal, 1900, Viil. II., p. 1,113. 



2 Asclepiad, i8go. 



3 " Death from Chloroform," by the author, Canadian Practitioner and Review, Feb., i8q8. 



4 British Medical Journal, i8gi. Vol. II., p. 1089. 



