40 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 2 



Typhoid fever is one of the most serious aihiients to which man is 

 subject. There are about 250,000 cases of this disease annually in 

 America, about 35,000 proving fatal. Sixty per cent of the deaths 

 in the Franco-Prussian War and 30% of the deaths of the Boer War 

 were caused by this disease. Positive statements have been made to 

 the effect that the house-fly was an active agent in the dissemination 

 of this disease, while certain reputable physicians consider this charge 

 unproved. The Spanish- American War, if it accomplished nothing 

 else, called attention in a most forcible manner to the part flies might 

 play in the dissemination of typhoid bacilli. Dr. M. A. Veeder of 

 Lyons, writing in 1898, was very strongly of the opinion that the 

 house-fly was largely responsible for the dissemination of this dis- 

 ease in camps. Dr. Walter Reed, writing of an outbreak near Porto 

 Principe in the annual report of the War Department, states that the 

 outbreak 'Svas clearly not due to water infection 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 dissem- 

 ination." Dr. L. 0. Howard, writing in 1899 on the fauna of human 

 excrement, quofts from Dr. Vaughan, a member of the army typhoid 

 commission, as follows : 



27. Flies iindonbtertly served as carriers of the infection. 

 My reasons for believing that flies were active in the dissemination of ty- 

 phoid 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 whitened with lime were seen walking over the 

 food. 



b. Officers 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 ap- 

 proach 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 second place, it is possible that 

 the typhoid bacillus may be carried in the digestive organs of the fly and 

 may be deposited with its excrement. 



Dr. Alice Hamilton in 1903, studying the part played by the house- 

 fly in a recent epidemic of typhoid fever in Chicago, which could not 

 be explained wholly by the water supply, nor on the grounds of pov- 

 erty or ignorance of the inhabitants, captured flies in undrained priv- 

 ies, on the fences of yards, on the walls of two houses and in the 

 room of a typhoid patient and used them to inoculate 18 tubes from 



