106 SCIENCE PROGRESS. 



cated from person to person it is by the inhaling the pes- 

 tiferous breath or exhalations which emanate from the body 

 of the patient. The communication of plague by inoculation 

 with the matter of a bubo or other morbid product has been 

 by no means proved ; on the contrary, there is every reason 

 to believe that the disease cannot be produced by these 

 means." Vague conceptions such as these are now fortu- 

 nately only rarely met with in medical literature since in- 

 quiries into the etiology of disease are at the present time 

 conducted by methods, and upon lines identical with those 

 that have advanced natural and physical science. 



On the 14th of June, 1894, Kitasato of Tokio discovered 

 the specific microbe of plague during an outbreak in Hong 

 Kong (3). Independently Yersin (4) made the same dis- 

 covery a few weeks later in the same year ; and to this 

 micro-organism, the pest-bacillus or Bacillus pestis bubonicce 

 the name of Coccobacillus pestis has been given by Metch- 

 nikoff (5). The majority of bacteriologists regard the 

 bacillus of Kitasato as identical with that of Yersin, but 

 according to Ogata (6), whose researches were made in 

 Formosa during 1896, this is by no means certain, and he 

 adduces among other evidence a statement to that effect 

 made by Kitasato himself. Although it is only to be ex- 

 pected that two original researches on the same subject 

 should exhibit certain differences, which undoubtedly did 

 exist as to the mode of growth, staining, behaviour and 

 motile power of the bacillus, the discrepancies between the 

 two observers are not sufficient to justify the attitude taken 

 by Ogata, Aoyama, Okada and other Japanese observers, 

 which aims at discrediting Kitasato's work. His researches, 

 however, are confined to the actual discovery of the bacillus 

 and the proof of its pathogenic nature. 



An excellent account by Kruse in the third edition of 

 Die M ikro-organismen, by C. Fliigge, contains all that was 

 known of the pest-bacillus in 1895, Dut si nce that date 

 numerous papers on this subject have appeared, and the 

 reports of the Scientific Commissions sent to India by most 

 European Governments for the purpose of studying the 

 outbreak of plague in that country have been published, 



