22 ANIMAL COMPETITORS 
bed-bug, may do this; but the most common 
agent is the flea. 
Another fact is that the rat seems especially 
susceptible to the disease; and, indeed, it is be- 
MOUTH-PARTS OF A RAT-FLEA, SHOWING WHERD BACILLI MAY 
CLING AND BE CARRIED INTO THE NEXT WOUND. 
From Doane’s ‘‘Insects and Disease.’’ By Permission of Henry 
Holt & Co. 
lieved that it was originally a disease of this 
rodent. Rats abound in fleas, and, as is the 
case with most furry or feathered animals, 
have a species peculiar to their race. This 
