126 THE HOUSE FLY—DISEASE CARRIER 
third experiment the infected flies were captured and 
killed. By means of sterile forceps their heads, wings, 
legs, and bodies were separated and respectively placed 
in sterile broth. Sub-cultures of the broth all gave a 
positive result. The authors conclude that M. domes- 
tica can convey B. typhosus from infected sources to 
objects upon which they walk, rest, or feed, and that 
bacilli adhere to the external parts of flies. ‘It has not 
been proved that the enteric bacillus passes through the 
digestive tract of the fly.’ 
“Hamilton (II. 1903) in Chicago, caught eighteen 
flies in and about houses and rooms occupied by ty¬ 
phoid cases, and states that she found B. typhosus in 
five of them. 
“Ficker (1903) caught flies in a house in Leipzig 
where eight cases of typhoid had occurred. He isolated 
B. typhosus from the flies. He carried out experiments 
with M. domestica kept in ten-liter flasks into which he 
introduced some sugar, strips of filter paper, and cul¬ 
ture of typhoid bacilli in bouillon. This was spread 
on the glass and partly absorbed by the filter paper. 
After eighteen to twenty-four hours the flies were trans¬ 
ferred to clean flasks. He found the flies to survive 
over four weeks in captivity if protected from the cold 
and fed on sugar, bread and water, or milk. He notes 
that flies may all die during a cold night, irrespective 
of typhoid bacilli being present in their food. The 
flies were transferred to clean flasks every two or three 
days. The flies to be examined were etherized and 
rubbed up in a mortar—the crushed material being 
