726 SCIENCE PROGRESS 



justify generalisation, difficult as it is to avoid it. The diseases 

 which in our country are disseminated by flies are all bacterial 

 and all mechanically conveyed. 



In passing it is worth recording that, contrary to the usual 

 statement that tsetse-flies are confined to the continent of Africa, 

 Captain R. M. Carter 1 has recently brought some back from 

 the Tabau River and from other localities in South Arabia. 

 Mr. Newstead has recognised the specimens as belonging to 

 the species Glossina tachinoides. It evidently does not live on 

 big game, since, except the gazelle, game is absent. The 

 Bedouins say that it bites donkeys, horses, dogs, and man, 

 but not camels or sheep. It is at times so troublesome as to 

 force the natives to shift their camps. 



The common house-fly has been known for some time to be 

 an active agent in the dissemination of bacterial diseases. In 

 intestinal disorders, such as cholera and enteric fevers, which 

 are caused by micro-organisms, the flies convey the bacteria 

 from the dejecta of the sick to the food of the healthy. In the 

 recent war in South Africa they are described in the standing 

 camps as dividing their activities " between the latrines and the 

 men's mess-tins and jam rations." 2 In the Spanish-American 

 War in Cuba, and in the South-African War, and in several 

 recent outbreaks of enteric fever in the British Army in India, 

 flies have been proved to be the carriers of the Bacillus typhosus. 

 Dr. Veeder 3 writes: "In a very few minutes they may load 

 themselves with dejections from a typhoid or dysenteric 

 patient, not yet sick enough to be in hospital or under 

 observation, and carry the poison so taken up into the very 

 midst of the food and water ready for use at the next meal. 

 There is no long roundabout process involved. It is very 

 plain and direct ; yet when thousands of lives are at stake in 

 this way the danger passes unnoticed." Similar records come 

 from the Boer camp at Diyatalawa in Ceylon. The bacilli are 

 conveyed direct just as they might be by an inoculating needle. 

 They do not pass into the body of the fly, neither do they 

 undergo any part of their life-history in its tissue. 



Dr. Sandilands 4 has recently investigated outbreaks of 



1 Brit. Med. Jonrn., No. 2394, November 17, 1906, p. 1393. 



2 Austen, Journal of the Royal Army Medical Corps, ii. 1904, pp. 651-67. 



3 Medical Record, vol. liv. 1898, pp. 429-30. 



4 Journal of Hygiene, vi. 1906, pp. 77-92. 



