687 



an appropriate claim to the attention of congressional decisionmakers 

 at the present time. 



The Evolution of Preventive Medicine 



Xothing is more international than disease. It recognjzes no political 

 boundaries and few natural ones. It moves freely across national 

 frontiers and spreads as conditions permit from one area to another. 

 The picture usually drawn is that of great pestilences moving from 

 backward regions to the more modern countries. But disease can also 

 go the other way, as shown in numerous accounts of aboriginal popu- 

 lations' becoming infected by the customary diseases of tlie missionary, 

 trader, explorer, and traveler. If one extends the problem to include 

 the diseases of plants and animals, there is little doubt today that 

 pathogenic organisms themselves are either already globally distrib- 

 uted or can rather rapidly become so. However, large numbers of these 

 organisms, and the diseases which they cause, remain largely seques- 

 tered in regions Avhere unsanitary conditions and certain insect vectors 

 prevail. These conditions are the reasons for tlie generally endemic 

 nature of such diseases as cholera, malaria, and plague in the less 

 developed countries. 



Preventive medicine, like disease, is inherently international. Had 

 there not been the problem of preventing the entrance of disease from 

 one country to another and of controlling the spread of disease v.ithin 

 countries, preventive medicine would not have developed as early as 

 it did. Public outcry demanded that corrective measures be taken 

 against recun-ing epidemics based upon the observed- association be- 

 tween polluted water and disease. Thus was born the first phase of 

 preventive medicine — sanitary engineering and public hygiene. 



Historically, the origin of this phase is marked by legislative Acts 

 in England like the Great Keform Bill of 18S2, the Metropolis Water 

 Act of 1852, and the Public Health Act of 1875. In England, at least, 

 the origin of preventive medicine and its early institutionalization as 

 a public health service was essentially a layman's movement. 



The scientific or experimental phase of preventive medicine, which 

 both overlapped and followed the sanitation movement, provided the 

 factual foundation upon Avhich sanitary water and sewage disposal 

 remain in their pt^sent practice. It also provided a foundation for 

 more intelligent decisions regarding the limitations of sanitation, and 

 on whether or not to quarantine and for how^ long. A ^ast array of 

 vaccines and other measures for the prevention and control of com- 

 municable disease evolved. This experimental phase of preventive 

 medicine can be called the era of bacteriolog;\\ Although as a discipline 

 it goes well beyond bacteriology, the early classical discoveries vrhich 

 revolutionized the nnders<-an(lin<r of e^^ideriic diseases were in that 

 field. The developments include the identification of the causative 

 organism of cholera by Robert Koch in 1883, the identification of the 

 plague bacillus by Kitasato and Yersin in 1894, the discoverv of the 

 gonococcus by Neisser in 1879, and of the typhoid bacillus 'in 18S0. 

 Henle had seen anthrax bacilli iii sheep in 'l850, Lister had killed 

 infectious bacteria in wound dressings in 1865, and Pasteur created a 

 wave of enthusiasm in 1880 following years of fascinating experi- 

 ments on liohalf of the French silk and wine industries. The microbe 

 causing yellow fever w^as not identified until 1927. but as noted else- 

 where in this study, Walter Reed and associates in the U.S. Army dis- 



