October 12, 1906.] 



SCIENCE. 



451 



things has taken the place of centuries-long 

 localization, a localization which sometimes 

 secured checks, antidotes or immunities. 

 Since, then, modern society can not help 

 incurring new risks, it should seek new 

 defenses. These defenses it may reason- 

 ably expect medical education to plan, and 

 public and private expenditure to provide. 



If civilized society is to endure under its 

 new exposures and dangers, it is clear that 

 the medical profession must take up with 

 new ardor the work of preventing ap- 

 proaching disease in addition to the work 

 of treating disease arrived. The profession 

 must recognize that health is eminently a 

 social product, just as the psychologists 

 have recognized that the mind of a civilized 

 man is a social product. 



When we consider what has already been 

 learnt about the production, transmission 

 and prevention of smallpox, cholera, yellow 

 fever, the black death, typhoid fever, diph- 

 theria, anthrax, rabies and tetanus, we can 

 not resist the conclusion that in the future 

 medical science must include the study of 

 causes and sequences which will carry the 

 student through a large portion of the 

 animal and vegetable kingdoms, and par- 

 ticularly into the habits and habitats of 

 their minute parasitic forms. Systematic 

 medical education must, therefore, produce 

 a considerable number of men capable of 

 studying in this region the causes of dis- 

 ease, and the ways of interrupting the 

 means of communication, or breaking the 

 chain of sequences, through which at last 

 the germs of disease get a chance to produce 

 their malignant effects within the human 

 body. Considering the great obscurity of 

 the physiological processes which go on 

 within the body and the dense ignorance of 

 mankind concerning the microscopic animal 

 kingdom, it is a great wonder that medical 

 science in its imperfect state has con- 

 structed so many effective defenses against 



disease within the last thirty years. In- 

 deed, we are now using some efficient de- 

 fensive methods, the real nature of which 

 we but imperfectly understand, as for in- 

 stance, the vaccinations against smallpox 

 and hydrophobia. Although we are not 

 yet able absolutely to prevent disease, we 

 are able in many cases to restrict the com- 

 munication of diseases and to modify their 

 course in the individuals attacked. 



The medicine of the future has, there- 

 fore to deal much more extensi-s^ely than in 

 the past with preventive medicine, or in 

 other words, with the causes of disease as 

 it attacks society, the community, or the 

 state, rather than the individual. The ob- 

 ject in view will be not only to arrest or 

 modify a malady which has appeared in 

 the body of a patient, but, as in the recent 

 case of yellow fever, to learn how the dis- 

 ease is communicated and how to prevent 

 that communication. The study of miti- 

 gations, remedies and cures is to continue; 

 but the study of the causes of disease and 

 the means of prevention is to be greatly 

 developed. The function of the nineteenth- 

 century physician will continue, and in- 

 deed will become more effective through a 

 better knowledge of the forces which may 

 be made to act upon his patient both from 

 within and from without; but another sort 

 of physician will be at work in the twen- 

 tieth century preventing the access of epi- 

 demics, limiting them when they arrive, 

 defending society against bad food and 

 drink, and reducing to lowest terms the 

 manifold evils which result from the con- 

 gestion of population. The explorers and 

 pioneers in medical science must be encour- 

 aged to press on their patient work of an- 

 alyzing all the processes which accompany 

 disease, in order that they may learn their 

 actual sequences. Only through the knowl- 

 edge of these sequences can real control 

 over disease be certainly gained. And this 



