OTHER INSECTS THAT TRANSMIT DISEASE GERMS 99 



it, and how it is spread, the authorities there have been able not 

 only to hold the disease in check, but practically to stamp it 

 out with the loss of comparatively few lives. 



" A small army of men was employed, catching rats in every 

 quarter of the city. Dr. Rucker reports that fully a million rats 

 were slain in this campaign. Their breeding places were de- 

 stroyed by making cellars, woodshed, warehouses, etc., rat- 

 proof and removing all old rubbish. Garbage cans were installed 

 in all parts of the city, as it was required that all garbage be 

 stored where rats could not feed upon it, and altogether every 

 effort was made to make it as uncomfortable as possible for the 

 rats. 



FIG. 58. Sucking insects that carry disease germs. 



A, tsetse fly, which carries the germs of sleeping sickness ; B, stable fly ; C, bed- 

 bug. (After Howard.) 



" The marked success attending this work abundantly con- 

 firms the soundness of the theory upon which it was based, and 

 serves as another example of the way in which science is teaching 

 us how to prevent or control many of our most serious diseases." 

 (Doane.) 



Blood-sucking Flies and Disease. Blood-sucking flies are 

 known to transmit the germs of sleeping sickness, and probably 

 carry those of infantile paralysis (polyomyelitis) and anthrax. 

 Sleeping sickness is prevalent in certain parts of tropical Africa. 

 It is caused by a minute protozoan parasite and is transmitted 



