468 
under which the plague invasion occurs. This is especially true when 
the medium of propagation is outside the human patient, and it is not- 
ably the case where rats are the agents. So far, in every case, the plague 
outbreaks in Japan were first evidenced in localities which have direct 
communication with foreign countries and from these points the spread 
to the regions of the interior occurred. Moreover, the first case in any 
place which subsequently became a source of plague was invariably 
associated with freight imported from India or from Hongkong. ‘The 
first epidemic owes its origin to a steamer which entered the port of 
Kobe with a cargo of raw cotton and Chinese rice from Bombay and 
Hongkong. The second one may be traced to a vessel which came to 
the port of Yokohama with freight consisting of raw cotton. The 
present great epidemic which prevails in Osaka and Kobe is due to a 
steamer which anchored in Kobe Harbor laden with a consignment of 
raw cotton from Bombay. ‘These statements demonstrate the almost 
identical origin of the fatal pestilence in each instance. 
As a rule, the plague germ on entering these trading ports does not 
immediately attack man; it first infects rats and by the time the first 
human victims are discovered, the epidemic has assumed a well-advanced 
form; this fact has been demonstrated on several occasions. ‘The present 
epidemic in Osaka may be considered as an example. In February it 
was preceded by the discovery of infected rats, but only during May of 
the same year did human victims begin to appear, thus showing how 
deep rooted was the source of the infection. 
The season during which an epidemic occurs has a marked influence. 
Thus it is apparent that a winter outbreak is generally of a most chronic 
character; it rages for a long period with great severity, spreading over 
a large extent of territory. The first invasion, the present epidemic in 
Osaka and Kobe, and the second one in Tokyo and Yokohama, belong 
to this class. A summer epidemic is usually acute in character and as 
a rule is spread by contagion. It may be severe though of short duration, 
and it is limited to a small area. The epidemics in Chiba and Kagawa 
during the past year and that of Hamamatsu in 1900 were of this nature. 
It should be noticed that during a winter epidemic a large number of 
infected rats are met with, while in a summer one but a small number 
or even no infected rodents are encountered. (See Pl. I.) 
PREVENTIVE MEASURES. 
As the plague epidemics in Japan, according to observation, originated 
in the Indian Peninsula, in Southern China, and in Formosa, the first 
and most urgent step to prevent the introduction of the disease was to 
establish quarantine against vessels coming from these regions. With 
this end in view, quarantine stations were erected at Yokohama, Kobe, 
Nagasaki, Moji and other principal trading ports and the necessary 
measures enforced as strictly as possible. So far, several cases of plague 
