igoo-i.] Observations on Blood Pressure. 187 



OBSERVATIONS ON BLOOD PRESSURE. 



WITH SPECIAL REFERENXE TO CHLOROFORM. 



By R. D. Rudolf, M.D., Edin., M.R.C.P. Lond., Toronto. 



{Read zjth April, igoi). 

 Introduction, 



This paper contains the results of work which I have conducted 

 during the past three years in the Physiological Department of Toronto 

 University. A grant of money was made by the Scientific Grants 

 Committee of the British Medical Association towards defraying the 

 expenses, and is here gratefully acknowledged. 



The work has been of a somewhat intermittent character, owing 

 chiefly to the difficulty in obtaining a steady supply of animals. The 

 kymograph used was a Ludwig one, with a glass pen writing in ink 

 upon white paper. The tracings thus obtained were very long, as often 

 experiments extended over several hours, and only short pieces of them 

 are able to be used here to bring out the points mentioned in the text. 



I have as far as possible avoided theorizing, being rather content 



to state the results which were actually obtained under given 



conditions ; a certain amount of speculation is occasionally inevitable 

 however. 



I am greatly indebted to Professor A. B. Macallum for much 

 valuable advice, and to Mr. Scott, D.Sc, for constant assistance in the 

 carrying out of the experiments. 



Before actually passing on to discuss alterations in blood pressure 

 produced by definite causes, one should mention that occasionally 

 strange falls in the blood pressure of dogs occur without any apparent 

 cause. If these were not noted they might be wrongly interpreted. 



I 



Tracing I. — 9/38. — Dog under Morphia. No Chloroform for several minutes. This fall in blood 

 pressure occurred without apparent cause and gradually disappeared. 



Tracing i shows one of these vagaries. The animal, a mongrel 



