8 NEW YORK STATE MUSEUM " 



The maggot, or more properly larva, is invariably whitish at 

 first, very small and when full grown only about yi of an inch 

 long. The body tapers from the large, nearly truncate posterior 

 extremity to the slender head. 



The resting or transforming stage known as the puparium, is 

 oval, brownish, ringed and scarcely }i of an inch long. 



The parent insect or adult fly is about % of an inch long, 

 rather slender, dull grayish and therefore easily distinguished 

 from the stouter, metallic blue or green bottle flies occasionally 

 seen in houses and especially about meats. 



A disease carrier.^ Typhoid fever is one of the most serious 

 ailments to which man is subject. There are about 500,000 cases 

 of this disease annually in America, about 50,000 proving fatal. 

 60^ of the deaths in the Franco-Prussian War and 30^ of the deaths 

 in the Boer War were caused by this disease. Dr M. A. Veeder 

 of Lyons in i8g8, was very strongly of the opinion that the 

 house fly was largely responsible for the dissemination of this 

 disease in camps. Dr Walter Reed writing of an outbreak near 

 Porto Principe in the annual report of the War Department 

 states that the outbreak '' was clearly not due to water infec- 

 tion but was transferred from the infected stools of patients 

 to the food by means of flies, the conditions being especially 

 favorable for this manner of dissemination." Dr Vaughan, a 

 member of the army typhoid commission, writes as follows re- 

 specting conditions in the Spanish-American War : 



27 Flies undoubtedly served as carriers of the infection. 



My reasons for believing that flies were active in the dissemi- 

 nation of typhoid may be stated as follows : 



a Flies swarmed over infected fecal matter in the pits and then 

 visited and fed upon the food prepared for the soldiers at the 

 mess tents. In some instances where lime had recently been 

 sprinkled over the contents of the pits, flies with their feet whit- 

 ened with lime were seen walking over the food. 



b Oflicers whose mess tents were protected by means of screens 

 suffered proportionately less from typhoid fever than did those 

 whose tents were not so protected. , 



c Typhoid fever gradually disappeared in the fall of 1898, with 

 the approach of cold weather, and the consequent disabling of 

 the fly. 



It is possible for the fly to carry the typhoid bacillus in two 

 ways. In the first place fecal matter containing the typhoid germ 

 may adhere to the fly and be mechanically transported. In the 



^For a bibliography of flies and disease, see N. Y. State Mus. Biil, 

 134, 1909. p. 32-40. 



