STUDIES ON PNEUMONIC PLAGUE AND PLAGUE 

 IMMUNIZATION. 



VI. BACTERIOLOGY. 



By flicHARD P. Strong and Oscar Teague. 

 (From the Biological Laboratory, Bureau of Science, Manila, P. I.) 



CONTENTS. 



Characters of the Pneumonic Strain of "Bacillus pestis." 



Morphology. 



Cultural characteristics. 



Mucus production. 



Virulence. 



Agglutination tests. 

 Infectivity of the Excreta of the Plague Patient. 

 Bacteriological Diagnosis of Pneumonic Plague from: 



Examination of the sputum and blood. 



CHARACTERS OF THE PNEUMONIC STRAIN OF ''BACILLUS PESTIS." 



During the epidemic in Manchuria the idea became rather 

 general that the organism of pneumonic plague differed, in 

 some respects at least, from Bacillus j^estis of bubonic plague. 

 Apart from cultural variations, some physicians believed that 

 while the bacillus of bubonic plague on inoculation into guinea 

 pigs gave rise to buboes, the bacillus of this epidemic, on injection 

 into these animals, caused only pneumonia and septicaemia. Also, 

 it was claimed by some, that the virulence of the organism of 

 pneumonic plague was much greater than that of the bacillus of 

 bubonic plague. These ideas were erroneous, as is apparent 

 from a consideration in detail of the properties of the pneumonic 

 strain arrived at from the study of numerous microscopical 

 preparations and cultures obtained from the sputum and from 

 necropsies performed during the epidemic. 



morphology. 



From a morphological standpoint, the causative organism of 

 the Manchurian epidemic of pneumonic plague apparently differs 

 in no respect from other strains of Bacillus pestis isolated during 



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