50 ANIMAL BIOLOGY 



and poisoned in large numbers. Plague patients were 

 carefully isolated, and the epidemic which had already 

 made considerable progress, was fortunately held in 

 check. Without the knowledge of the parts played by 

 the flea and the rat in the dissemination of this terrible 

 disease the country might have been swept over a scourge 

 that would have claimed many thousands of victims. 



