84 
BACTERIOLOGY. 
cellent results have been obtained by the use of Sclavo’s 
serum and Eichorn’s serum given intravenously. 
The Bacillus of Plague (Bacillus Pestis). 
The bacillus of bubonic plague was discovered by 
both Kitasato and Yersin during the epidemic in China 
in 1893. It is a short, thick, Gram negative, bacillus 
with rounded ends. In old cultures atypical forms are 
found, some like cocci, others club-shaped like the 
diphtheria bacillus. It is not motile and does not form 
spores. It will grow only in the presence of oxygen. 
In dark, moist places the organism will live for months 
or years. In the sputum and pus from patients it lives 
for one or two weeks. In cadavers they may live for 
several weeks. Dry heat destroys the bacillus in one 
hour, boiling in a few minutes. Direct sunlight re¬ 
quires four or five hours. Carbolic acid (5 per cent.) 
and bichloride of mercury (1: 1000) destroy them in 
ten minutes. 
The plague raged from the sixth to the seventeenth 
century, and in the fourteenth century the black death, 
as it is called, destroyed one-quarter of the population 
of Europe. The great plague in London in 1665 des¬ 
troyed 70,000 people. The disease subsided then and 
remained practically dormant until 1894, when it 
broke out in Hong Kong. It spread thence to other 
countries, and a small epidemic occurred in San Fran¬ 
cisco in 1907. In India the disease is endemic and 
annually causes the death of 500,000 people. 
The infection may enter through the skin or by 
