116 SANITARY ENTOMOLOGY 



It is of interest to note that in nineteen species the organism has been 

 proven to pass freely through the intestinal canal of the larvae, in thirty- 

 seven species through the intestines of tlie adult, and in eleven species 

 to be capable of persisting in the larvae through metamorphosis to the 

 adult. What greater argument could be found that flies are dangerous 

 not only because of what they as flies have fed on, but also because of 

 food they took while larviE, possibly a long distance away? 



We have not, however, gauged the depth of the fly's infamy, as we have 

 so far only listed the evidence of plant diseases transmitted. 



DISEASES OF UNSETTLED ORIGIN PKOBABLY CAUSED BY 

 MICROORGANISMS 



PURULENT OPHTHALMIA is said to be carried by flies in Egypt. 

 Brumpt accused Musca domestica of being a carrier of TRACHOMA. 

 Rosenau stated that flies have been found breeding in open lesions of 

 SMALLPOX, and that flies may transmit MEASLES and SCARLET 

 FEVER. Definite experiments certainly should be carried out with a 

 view to determining the exact relationship of flies to these diseases, seek- 

 ing first the possibility of transmission by fecal contamination. 



Howard and Clark (1912) found that Musca domestica flies can 

 retain the virus of INFANTILE PARALYSIS or POLIOMYELITIS 

 either in or on their bodies for 24 and 48 hours. The virus may remain 

 alive in the body of the fly six hours after ingestion. The fly can obtain 

 the virus from secretions of nose and throat and discharge of intestines. 



Very recently Dorset (1919) and associates have experimentally 

 transmitted HOG CHOLERA by inoculating with crushed bodies of 

 infected Musca domestica and Fannia canicularis, and also by bringing 

 such flies in contact with abraded surfaces. 



ANIMAL ORGANISMS CARRIED BY NON-BITING FLIES 



We will now consider in a similar manner the evidence of transmission 

 of animal organisms by these same flies. 



Protozoa 



Sarcodina: Amoebima: Amoebidae 



Loschia coli (Losch) (Endamoeha) a supposedly harmless commensal 

 in the alimentary canal of man, where it feeds on the contents of the. 

 bowels, may be carried in the encysted form by Musca dovwstica, accord- 



