PREVENTIVE MEDICINE. 353 



Japanese bacteriologist, Kitasato, who had received his training in 

 the laboratory of the famous Professor Robert Koch, of Berlin. This 

 discovery was made in the month of June, 1894, in one of the hospitals 

 established by the English officials in Hong Kong. About the same 

 time the discovery was made, independently, by the French bac- 

 teriologist, Yersin. From this time the study of the plague has been 

 established upon a scientific basis and very material additions have been 

 made to our knowledge with reference to the prevention and 'treatment 

 of the disease. 



That the plague bacillus has not lost any of its original virulence 

 is amply demonstrated by the high death-rate among those attacked, 

 and we are justified in ascribing its restricted prevalence to the gen- 

 eral improvement in sanitary conditions in civilized countries and to 

 the well-directed efforts of public health officers in the various locali- 

 ties to which it has been introduced during recent years. In the 

 Philippine Islands, where it prevailed to a considerable extent when 

 our troops first took possession of the City of Manila and where the 

 conditions among the natives are extremely favorable for its extension, 

 it has been kept within reasonable bounds and, indeed, the latest reports 

 indicate that it has been practically exterminated by the persistent 

 efforts of the medical officers of our army, charged with the duty of 

 protecting the public health in those Islands. 



The monthly report of the Board of Health for the city of Manila 

 for September, 1902, the last at hand, records but one death from 

 plague during that month. During the same period there were ten 

 deaths from typhoid fever, thirty-five deaths from dysentery and 

 seventy-six deaths from 'the great white plague,' pulmonary tuber- 

 culosis. 



Bubonic plague, cholera and typhoid fever have long been classed 

 as 'filth diseases,' and in a certain sense this is correct, although we 

 now know that the germs of these diseases not only are not generated 

 by filth, but do not multiply in accumulations of filth. They are 

 present, however, in the alvine discharges of the sick, and when this 

 kind of filth is exposed in the vicinity of human habitations or gains 

 access to wells or streams, the water of which is used for drinking, the 

 germs are likely to be conveyed to the alimentary canals of susceptible 

 individuals, and thus the disease is propagated. Until quite recently 

 the attention of sanitarians was so firmly fixed upon the demonstrated 

 transmission of cholera and typhoid fever through the agency of con- 

 taminated water or milk that certain other modes of transmission were 

 overlooked, or at least underrated. I refer to the transmission by 

 insects, or as dust by currents of air. I have for many years insisted 

 upon the part played by flies as carriers of infectious material from 

 moist masses of excreta from cases of cholera and typhoid fever. There 



VOL. LXII. 23. 



