FLIES AND TYPHOID FEVER. 



251 



standpoint, but from a desire to learn the principal source from which 

 our houses are supplied with this eternal nuisance, with a view to 

 being able to suggest remedial measures. Experimental work in this 

 direction was continued for some years. In the course of this work he 

 early decided that an overwhelming majority of the house-flies found in 

 domiciles breed in horse manure. This substance is its favored larval 

 food, and experimental work showed that by the semi-weekly treatment 

 of the horse manure in one large stable, the house-fly supply of the 

 neighborhood was very greatly reduced. In confined breeding cages he 

 had been unable to breed house-flies in any other substance than horse- 

 dung, and consequently when the camp typhoid question and the agency 

 of flies became a matter of such general comment in 1898, he saw the 

 desirability of a careful study of the insects which frequent or breed in 

 human excrement, in order to give exact data from which reliable state- 



Fig. 2. Sepsis violacea— enlarged. 



Fig. 3. Nemopoda minuta- 

 enlarged. 



ments could be made and upon which reliable conclusions could be 

 based. This work was begun and carried on through the summer of 

 1899 and to some extent in the summer of 1900, with results which will 

 be briefly summarized in the following paragraphs. The exact details, 

 somewhat too technical, altogether too long and certainly too un- 

 pleasant for publication in a journal of this character, will be published 

 in the Proceedings of the Washington Academy of Sciences. 



In all seventy-seven distinct species of flies, belonging to twenty- 

 one different families, were found by actual observation, either by 

 rearing or by captures, to be coprophagous; thirty-six species were found 

 to breed in human fasces under more or less normal conditions, while 

 forty-one were captured upon such material. All have been studied 

 with more or less care, and their other habits ascertained. The most 



