544 



HOWARD 



of Tizzoni and Cattani, Savvtchanko, Simmonds, Uffelmann, 

 Flugge and Macrae, while Celli had shown as early as 1888 

 that flies fed on the pure cultures of Bacillus typhi abdom'inalis 

 were able to transmit virulent bacilli into their excrement. Dr. 

 Geo. M. Kober, of Washington, D. C, in his lectures before 

 the Medical College of Georgetown University, for some years 

 had been insisting upon the agency of flies in the transmission 

 of typhoid, and in the report of the Health Officer of the Dis- 

 trict of Columbia for the year ending June 30, 1895, referred 

 to the probable transference of typhoid germs from box privies 

 and other receptacles for typhoid stools to the food supply of 

 the house by the agency of flies. 



In the winter of i898-"99 an admirable paper by Dr. Geo. 

 H. F. Nuttall, entitled ' On the Role of Insects, Arachnids and 

 Myriapods as Carriers in the Spread of Bacterial and Parasitic 

 Diseases of Man and Animals ; a Critical and Historical Study,' 

 was published in Volume VIII of the Johns Hopkins Hospital 

 Reports. In this volume the previously published literature of 

 the subject was carefully reviewed and the agency of flies in 

 the transmission of intestinal diseases was made reasonably 

 apparent. 



In all this literature, however, the expression used in connec- 

 tion with insects was simply the word ' flies.' It seemed as 

 though it were intended by the writers to mean either that all flies 

 were concerned, or that there was but one kind of fly — presum- 

 ably the house fly. It did not seem to be realized that there 

 are many species of flies which are attracted to intestinal dis- 

 charges, nor did it seem to be realized that while certain of 

 these species may visit and do visit food supplies in dining- 

 rooms, kitchens or elsewhere, many others are not likely to be 

 so attracted. It occurred to the writer, therefore, during the 

 summer of 1898 that from the scientific point of view and pos- 

 sibly also from the practical point of view there was a distinct 

 necessity for careful investigation of the insect fauna of human 

 excrement, especially of the flies which breed in human fgeces 

 or are attracted to them. Such an investigation was therefore 

 begun and carried on, the main work being done during the 

 summer of 1899. The results are contained in the present 

 paper. 



