"10 



SCIENCE. 



[N. S. Vol. XX. No. 517. 



tuberculosis and typhoid fever— to reflect 

 upon how far cholera and plague have lost 

 their terrors — to contemplate the brilliant 

 results of the discovery by Ross and the 

 Italian school of the life history of the 

 malarial parasites as manifested in the 

 anti-malarial campaigns carried on in vari- 

 ous regions by Koch, and in Italy by the 

 Society for the Study of Malaria, a noble 

 institution of which our Latin brothers 

 may well be proud, and lastly, to look upon 

 the beneficent and far-reaching influence 

 of the recent work of Reed and Lazear and 

 Carroll and Agramonte with regard to 

 yellow fever, to realize what bacteriological 

 and parasitological studies are doing for 

 preventive medicine. 



But beyond this external prophylaxis, 

 the studies of the problems of immunity 

 beginning with Pasteur's inoculations 

 against anthrax in 1881, have given us, so 

 to speak, an internal prophylaxis, a func- 

 tional prophylaxis if one will, in the possi- 

 bility of producing a greater or less degree 

 of individual immunitj^ such, for instance, 

 as is now possible in diphtheria, cholera, 

 plague, typhoid fever and dysentery. 



The enforcement of scientifically planned 

 and accurately deduced prophylactic meas- 

 ures has become to-day one of the main 

 duties of the practitioner of medicine. It 

 is as much the task of the physician nowa- 

 days to guard over the disposal of the 

 sputa of his tuberculosis patient, of the 

 excreta of the sufferer from typhoid fever 

 or cholera or dysentery, as it is to attend 

 to the immediate wants of the invalid. 

 How rapidly has the exact replaced the 

 conjectural in this branch of medicine ! 



But while diagnosis and prophylaxis 

 were being removed from the domain of 

 conjecture to the field of exact observation 

 and reason and research, while the possi- 

 bilities of surgery were rapidly widening 

 through the discovery of aneesthesia and 

 the introduction of antiseptic methods, 



medical treatment, until the last two 

 decades, still remained largely empirical. ' 

 The development of exact clinical methods 

 of observation and the statistical tabulation 

 of experience for which we are especially 

 indebted to Laennec and Louis and their 

 followers, gradually brought about, to be 

 sure, many advances, while a large number 

 of useful therapeutic agents introduced by 

 the newly developed science of pharmacol- 

 ogy, and exactly tested by improved meth- 

 ods of physiological study added greatly 

 to the armamentarium of the physician 

 for the relief of symptoms. The power to 

 combat disease specifically, however, re- 

 mained much as it was at the beginning of 

 the century. Mercury in syphilis, quinine 

 in malarial fever, were the only specifics 

 known to the medical world— and the ac- 

 tion of these was unexplained. 



The introduction by George Murray, less 

 than fifteen years ago, of the treatment of 

 myxoedema and allied conditions by ex- 

 tracts of the thyroid gland, was a direct 

 application of the results of physiological 

 observation to the treatment of disease. If 

 this gave rise to hopes of the possibility of 

 obtaining like results from roughly ob- 

 tained extracts of other ductless glands, 

 which have hardly been fulfilled, yet this 

 discovery was the first step toward the 

 rational scientific therapy to which we are 

 beginning to look forward to-day. 



But a moment ago I spoke of the impor- 

 tance of the influence of the discovery of 

 the causal agents of the infectious diseases 

 upon the development of exact diagnostic 

 and prophylactic methods. Great and im- 

 pressive as these have been, yet the studies 

 which have followed as to the manner in 

 which these agents act upon the human 

 organism, and of the powers of resistance 

 which the body exerts against them, the 

 investigation of the problems of immunity, 

 have opened out a far wider field. The 

 early studies of Metschnikoff and Buchner 



