102 INFECTION AND IMMUNITY 



for competent bacteriologists to make scientific in- 

 vestigations relating to the specific cause of this 

 scourge of the human race and to the demonstration 

 that it is due to a minute bacillus. This discovery 

 was first made by the Japanese bacteriologist, Kita- 

 sato, 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 

 bacteriologist, 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 general 

 improvement in sanitary conditions in civilised coun- 

 tries and to the well directed efforts of public health 

 officers in the various localities 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 



