BY DR. A. JEFFERIS TURNER, M.D. LOND., D.P.H. CAMB. 115- 
private interests, and public convenience. In pursuance 
of this policy, every occurrence of plague was notified to. 
the police, and not only the patient, but every one on the 
premises, and in the case of an hotel, their number might 
be considerable, was conveyed to the Quarantine Station, 
on the other side of the harbour. These proceedings 
certainly made a great stir, and had an appearance of: 
energy. But I found to my surprise that the highest 
authorities in the Department of Health held views as to 
the epidemiology of plague, which were, to put it mildly, 
hardly consistent with these administrative measures. 
To them the infectiousness of plague from patient to patient 
was very problematical, and played very little if any, part 
in spreading the epidemic. They regarded plague rather 
as a disease of the rat, occasionally communicated to man- 
kind, probably by the bite of rat-fleas, and therefore 
requiring for its prophylaxis entirely different measures 
from those that I have described. While excellently 
devised to stamp out an epidemic of small-pox, isolation 
and segregation of contacts were, they considered, quite 
inoperative in the case of plague, except in so far as they 
facilitated the cleansing of affected dwellings and areas. 
and the destruction of rats. 
To understand how this position was arrived at, we must 
briefly recapitulate the position at that time of scientific 
knowledge segarding plague. The discovery of the bacillus 
of plague was made in Hongkong in 1894 by Kitasato and 
Yersin, and since then there has been no room for doubt 
that the bacillus pestis is the causal organism. But its 
method of spread from case to case long remained a matter 
for conjecture. One of the characteristics of the plague 
organism in artificial culture is its slight power of resistance 
to unfavourable conditions. 1t behaves in the laboratory 
rather like a frail exotic, and in mixed cultures is readily 
killed out by more vigorous saprophytes. It does not 
survive long when dried in the ordinary way, and the 
conjectures that plague may be due to food or soil contamina- 
tion had never any solid foundation. Again on the assump- 
tion that the disease is infectious it is difficult to understand 
how the bacilli make their exit from the patient. Certainly, 
in the rare cases of pulmonary plague, the bacilli are con-- 
