FLEAS 153 



the sweepings of rooms that contained no blood at all. 

 Multitudes of fleas often develop in a house left empty 

 during the summer. It is very probable that the only 

 food found by the larvae under such circumstances is the 

 organic matter in the cracks and crevices of the floor, 

 about the baseboards, in the corners, under the carpets, 

 and in similar places. 



THE RELATION OF FLEAS TO DISEASE 



Fleas are now known to be active and menacing agents 

 in the conveyance of disease, especially the bubonic 

 plague. 



In India, where the bubonic plague often decimates 

 the native inhabitants, careful experiments have demon- 

 strated that the rat flea found in tropical and subtropical 

 countries readily takes this plague bacillus from infected 

 rats and inoculates other rats with it ; that the plague 

 bacillus multiplies in the stomachs of fleas and that the 

 bacilli are found in the feces of fleas taken from dead 

 infected rats ; that the bubonic plague does not persist 

 in a locality apart from infected rats ; that the rat flea 

 will make use of man as a host and may be captured in 

 large numbers on men in houses infested with rats ; and, 

 lastly, that evidence proves the rat flea as the trans- 

 mitting agent of bubonic plague infection from rat to man. 



Verjbitski, as a result of an important series of experi- 

 ments that he made in 1902 and 1903, comes to the follow- 

 ing conclusions, among others, concerning the relation 

 of fleas to the bubonic plague : — 



"All fleas and bugs which have sucked the blood of 

 animals dying from plague contain plague microbes. 



