660 



SCIENCE. 



[N. S. Vol. XX. No. 516. 



bacteriology has sustained close and mu- 

 tually advantageous relations with, the 

 science of medicine. This has been the 

 scene at once of its greatest endeavors 

 and of its greatest triumphs. To recount 

 these would be superfluous. There is 

 hardly an hypothesis in scientific medicine 

 that has not been freshened and modified, 

 hardly a procedure in practice that has 

 not been influenced by bacteriological con- 

 ceptions. The experimental method in par- 

 ticular has been given new support and 

 received brilliant justification. Experi- 

 mental pathology and experimental phar- 

 macology practically owe their existence to 

 the methods and example of bacteriology. 

 The security afforded by aseptic surgery 

 has made possible physiological exploits 

 that could not otherwise have been dreamed 

 of, a pregnant illustration of the way in 

 which applied science may directly further 

 the advance of pure science. Conspicuous 

 as these achievements of bacteriology have 

 been, it can not be truly said that the field 

 is exhausted. There is hardly an infectious 

 disease of known or unknown origin that 

 does not still harbor many obscurities. 

 Some of the most difficult problems that 

 medicine has to face are connected with 

 the variation and adaptation of pathogenic 

 bacteria. The phenomena of immunity, 

 certainly among the most complicated and 

 important that human ingenuity has ever 

 set itself to unravel, still await their full 

 description and interpretation. The study 

 of the ultra-microscopic, or perhaps more 

 correctly the filterable viruses, is being 

 prosecuted with great energy and in a 

 sanguine spirit. The extension of bac- 

 teriological method into the field of pro- 

 tozoon pathology has been already referred 

 to and constitutes one of the latest and 

 most hopeful developments in. the study of 

 the infectious diseases. Medicine, perhaps 

 more than any other department of human 

 knowledge, is most indebted to, and main- 



tains the most intimate relations with, the 

 science of bacteriology. 



At the present time the relations of bac- 

 teriology to public hygiene and preventive 

 medicine seem to me of particular impor- 

 tance, and it is upon this theme that I wish 

 chiefly to dwell. Personal hygiene is not 

 necessarily pertinent to this topic, but falls 

 rather into the same province with the 

 healing art. Matters of diet, of clothing, 

 of exercise, of mental attitude affect the 

 individual and contribute more or less 

 largely to his welfare. But except in so 

 far as the individual is always of moment 

 to the community, they do not affect the 

 larger problems of public hygiene. The 

 pathological changes that take place in the 

 tissues of the diseased organism and the 

 methods that must be employed to combat 

 the inroads of disease in the body of the 

 individual patient must for a long time to 

 come remain questions of supreme impor- 

 tance to the human race. But over and 

 above the treatment and cure of the dis- 

 eased individual, and the investigation of 

 the processes that interfere with the proper 

 physiological activities of the individual 

 organism, rises the larger and more far- 

 reaching question of the prevention of 

 disease. 



Racial and community hygiene are but 

 just beginning to be recognized as fields 

 for definite endeavor. The project may 

 seem vast, but the end in view is undoubt- 

 edly the promised land. More and more 

 will the problems of curing an individual 

 patient of a specific malady become subor- 

 dinated to the problem of protection. 

 More and more will scientific medicine oc- 

 cupy itself with measures directed to the 

 avoidance of disease rather than to its 

 eradication. 



Whatever else may be said of it, this is 

 certainly the age of deliberate scrutiny of 

 origins and destiny. Man no longer closes 

 his eyes to the possibilities of future evolu- 



