‘24 ANIMAL COMPETITORS 
It is now understood that the first thing to 
do when a case of plague is brought to some 
port ‘in a ship’ sailing from the Orient is to 
exterminate the rats of the locality; and the 
best preventive against this and other afflictions 
getting a foothold anywhere, is to keep the rats 
down. The Japanese were quick to take ad- 
vantage of the new knowledge, and by the fierce 
crusade. they’ waged against the wharf-rats in 
their ports prevented a spread of bubonic 
plague, always threatening them, in the armies 
they sent into Manchuria. In this way, too, by 
a vigorous crusade against the animal in Cali- 
fornia, ih which many hundreds of thousands 
were trapped or poisoned, the plague was re- 
cently eradicated in San Francisco before ‘it 
‘had reached alarming ‘proportions. 
Rats and trichine. But rats disseminate 
diseases other than bubonic plague. ‘Trich- 
imosis among. Swine is probably perpetuated 
entirely by rats, since trichine in the hog can 
result only from its eating the flesh of animals 
infested with ‘the parasite. The only two an- 
imals of the farm-known to be subject to this 
