MEDICAL ENTOMOLOGY — HOWAED. 581 



studied by Plotz in New York, and American and English physi- 

 cians soon decided that it also was louse-borne, and measures were 

 at once instituted to control lice in camps and entrenchments. An 

 enormous amount of experimentation was undertaken as to the best 

 means of destroying lice, not only on the person but in temporarily 

 discarded clothing — toward the close of the war with great success. 

 Troops moving from country to country or returning from the front 

 were fumigated and their clothing was steamed or fumigated, and 

 all American troops returning from Europe were put through one 

 process or the other. 



Without the slightest doubt in the world, there are many species 

 of insects which act as carriers of disease in a purely mechanical way. 

 There are many species which are attracted to exposed foods which 

 are also attracted to excreta, to sputa, and to other substances carry- 

 ing disease germs. This fact has, however, only recently become a 

 matter of general information. The carriage of Asiatic cholera by 

 flies was considered most probable by a number of earlier writers, 

 but nothing seems to have been placed on record with regard to the 

 very certain carriage of typhoid fever by the house fly until the late 

 nineties. Kober in a report of the Health Department of the Dis- 

 trict of Columbia on an investigation of a small epidemic of typhoid, 

 suggested the contamination of milk by the house fly, which had pre- 

 viously visited the excreta of typhoid patients. The subject was 

 brought prominently before the public during the Spanish- American 

 war. Although the Surgeon General of the Army, Doctor Sternberg, 

 gave careful instructions regarding the disposal of the excreta in con- 

 centration camps, his orders were not well carried out, and typhoid 

 became epidemic at many points. A commission of Army surgeons, 

 consisting of Doctors Reed, Shakespeare, and Vaughan was ap- 

 pointed and their . full report indicated that under concentration 

 camp conditions the terrible spread of typhoid was due almost 

 entirely to the common house fly. During that brief war SO per cent 

 of the total deaths were caused by typhoid. From that time on the 

 control of the house fly became a very important subject, and many 

 volumes and hundreds of pamphlets have been written giving the 

 results of careful studies of the biology of the house fly in all its 

 aspects and of methods of control. Later vaccination against 

 typhoid was discovered and proved to be so effective that control of 

 flies in camps became less important. The house fly is nevertheless 

 a very dangerous species and is a very important factor in the spread 

 of infantile diarrhoea in the summer months and in other ways is a 

 constant menace to health. The necessity for laboratory proof of 

 its carriage of typhoid and other diseases of the same general nature 

 which has been insisted upon by Graham-Smith and other writers, 



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