The Plague of Flies. 19 



None, so far as I know, has undertaken to compute the 

 annual damage to man by the fly family all over the 

 world. I suppose there is no use stringing figures clear 

 across the page, and I am not sure that one line of them 

 would be enough. There would have to be the construc- 

 tive damage in such instances as the rendering uninhabit- 

 a b 1 e of countries like 

 South Africa, where the 

 bite of the tse-tse fly is in- 

 variably fatal to horses, 

 oxen, and dogs, without 

 which it is practically im- 

 possible for man to engage 



in agriculture. p ' s- I- Compsomyia macellaria. 



The screw-worm fly, adult, wings 

 In OUr OWn COUlltry expanded. 



those who saw the tottering 



wrecks of soldier boys come home from Tampa, where 

 they quarreled with the flies for their food, need no argu- 

 ment to convince them that the flies carried the typhoid 

 germs from latrine to mess-table and slew the flower of 

 our young men by hundreds and thousands. The War of 

 the Rebellion proved conclusively that flies inoculated 

 every open wound with gangrene. The terrible " malig- 

 nant pustule " is now known to be caused by the bite of 

 gad-flies which have come from cattle diseased with an- 

 thrax. 



The purulent ophthalmia almost universal in Egypt 

 is the work of the common flv, and these verv small 



f * 



flies that lay their vinegar-proof eggs in pickle-jars 

 get into folks' eyes in the Southern States. More than 

 once they have brought on such epidemics of " pink- 

 eye " in Florida that the schools have had to be closed. 

 Asiatic cholera is now so universally known to be spread 

 by flies that it is almost unnecessary to speak of it. 



