704 



SCIENCE 



[N. S. Vol. XLII. No. 1090 



Putting aside for the present the impli- 

 cation in the expression "mere curiosity" 

 which we hear so often in this connection 

 I may answer that it is now possible to 

 measure the blood pressure in man without 

 resort to the method of Hales; no blood 

 vessel has to be opened and no pain has to 

 be inflicted. Blood pressure determination 

 forms a part of every examination for life 

 insurance, and of the routine of nearly 

 every present-day medical examination. In 

 certain conditions its measurement is of the 

 most extreme importance. It gives exact, 

 quantitative information on the state of the 

 heart and blood vessels that could be ob- 

 tained in no other way. And the useful- 

 ness of this information so far from being 

 confined to diagnosis of disease of these 

 organs themselves is quite as important in 

 the light it throws on the functioning of 

 other organs. 



I have given this rather disproportion- 

 ately long statement of the physiology of 

 the circulation to make very specific what 

 I mean in saying that the importance of 

 most investigations is to be found not in the 

 direct application of the specific discoveries 

 but in the reflex effect of these on aU related 

 work. Antivivisectionists use the knowl- 

 edge which has been obtained by experi- 

 ments on living animals. No modern 

 physician can for a single hour free him- 

 self from the deepest obligation to vivisec- 

 tion experiments, although he may never 

 himself have made such experiments. 



It is quite true that human blood pres- 

 sure may now be determined without open- 

 ing an artery and that the principles may 

 now be explained without appeal to animal 

 experiments; but I believe it to be equally 

 true that this would not now be possible, 

 and that neither the method of blood pres- 

 sure determination nor its significance 

 would now be known if the long series of 

 vivisections had not first occurred. 



In this connection it will be appropriate 

 to say a word about surgical shock. Every 

 one realizes that as surgery is practised 

 today the chance of coming out of a major 

 surgical operation is always good, yet it is 

 no light matter; there is usually real dan- 

 ger; and the memory still remains with us 

 of friends or acquaintances who in an 

 otherwise not serious operation succumbed 

 to shock. Shock is a peculiar complex not 

 easy to define. There is not usually the 

 suddenness which the word implies to the 

 lay mind ; but there is a great depression of 

 the functional activities; and most marked 

 of aU its symptoms is an excessive fall of 

 blood pressure. To discover the real nature 

 of shock and thus to furnish the surgeon 

 the means of its avoidance is no small boon 

 to humanity. "With this purpose in view 

 many researches have been carried on. It 

 has not been easy to find the true cause of 

 the lowered blood pressure but much prog- 

 ress has been made. Perhaps no one man 

 has made such untiring efforts to the solu- 

 tion of this problem as George W. Crile, and 

 for this he has been denominated "brute," 

 "savage," "arch fiend," "torturer" and 

 almost every other term which fanaticism 

 can devise. And yet it is to Crile and the 

 system of anoci-association which he has 

 worked out that every man or woman who 

 has to undergo a major surgical operation 

 owes a debt of gratitude which he can never 

 repay ; for not only does this method, where 

 applicable, reduce the immediate danger 

 from surgical shock, but it also greatly re- 

 duces or wholly sets aside the long period 

 of nervous impairment which so commonly 

 follows recovery from an operation in which 

 these principles are disregarded. 



I have selected the history of the study 

 of blood pressure on account of its com- 

 parative freedom from those details which 

 appeal to the emotional and dramatic side 

 of human nature. I have used it to illus- 



