DISEASES BORNE BY NON-BITING FLIES 107 



them out whole m the feces, but in all his experiments with the larvae he 

 found that the eggs were crushed. 



In addition to tlie ability of flies to carry disease germs in their 

 body, there are multitudes of proofs of their ability to carry them also 

 on their body and to deposit them when they feed. 



The transmission of disease hy non-hlood sucking flies is exclusively 

 hy contamination either of food, water or wounds. Most of the flies 

 which frequent houses and food or visit man because of attractive secre- 

 tions or injuries also are attracted to and breed in excreta or garbage. 

 Hence the contamination of food by direct transportation from infected 

 excreta is a very simple matter. 



This contamination may be by the simple depositing of disease 

 germs carried on the body of the flies, or by regurgitation, or the 

 deposition of feces. Wherever a fly alights and remains a few minutes 

 it deposits either vomit or feces. By the nature of its breeding it is 

 hardly to be expected that these deposits will not contain some kind of 

 bacteria, and possibly^ protozoa or worm eggs. If these deposits are 

 made on the moist media off'ered by foods the germs may easily retain 

 their virulence until eaten. 



As flies can travel considerable distances, at least thirteen miles, 

 the existence of a single disease case with insanitary conditions in the 

 vicinity enabling fly breedimg, might easily infect an entire city or army 

 camp if the flies were permitted to reach the food of the inhabitants. It 

 is because of the total lack of sanitary waste disposal in country dis- 

 tricts that diseases like typhoid fever and dysentery usually become very 

 widespread. We can not know the source of the -flies which enter our 

 houses. We must not let them visit our food. They must be kept away 

 from the eyes and mouths of babies. Our markets where meats and 

 vegetables are sold must be better protected. Only througli influencing 

 public opinion will we be able to have the fly nuisance in our own public 

 markets abated. Food offered for sale shoidd be kept under glass or 

 screen at all times. 



There are so many organisms transmitted by the non-blood-sucking 

 flies that we shall have to deal with them rather briefly and preferably 

 according to their classification. A thorough digest of the mass of 

 matter submitted below should impress the readers with the necessity 

 of fly prevention. 



PLANT ORGANISMS CARRIED BY NON-BITING FLIES 



Thallophyta: Fungi: Schizomycetes: Coccaceae 



Streptococcus equinus Andrewes and Horder, a non-pathogenic organ- 

 ism found in horse dung, was found by Torrey (1912) in a number of 

 cases on the surface of city caught flies. 



