140 BACTERIOLOGY FOR NURSES 



50 per cent to 95 per cent, Yersin reporting the 

 latter after the Hong Kong epidemic in 1894. 



Race mortaUty shows also a wide variation, but it 

 is attributed rather to differences in social condi- 

 tions than to physical differences of the races. At 

 Hong Kong the mortality was 93.4 per cent among 

 Chinese; 77 per cent among Indians; 60 per cent 

 among Japanese; 100 per cent among Eurasians; 

 and only 18.2 per cent among Europeans. 



There are two forms of plague in man: the bubonic 

 and plague pneumonia. The bubonic form often 

 passes into a septicaemic form when the baciUi pass 

 from the buboes into the blood. There are some- 

 times subcutaneous hemorrhages, causing dark 

 spots, from which the name "black death" no doubt 

 originated. In plague pneumonia, which is much less 

 frequent than the bubonic type, the sputum con- 

 tains enormous numbers of bacilli; this form of 

 plague is usually fatal. 



Modes of Infection and Transmission. — Poverty 

 and filth may be considered the two greatest con- 

 tributing factors in the continuance and spread of 

 plague. In the middle ages the hygienic condition 

 of the whole world was identical with those found at 

 present in China and India. 



The "infectious droplets^' from the pneumonic 



