CARRIAGE OF DISEASE 
125 
Exact Proof 
From the laboratory point of view, a number of ex¬ 
act experiments have been made, and we quote the fol¬ 
lowing paragraphs from Nuttall and Jepson: 
“Celli (1888) fed flies with pure cultures of the 
Bacillus typhosus and examined their contents and de¬ 
jections microscopically and culturally. Inoculations 
on animals were also made, proving, as he supposed, 
that the bacilli which passed through flies were viru¬ 
lent. (He made similar observations with the Spiril¬ 
lum Finkler-Prior.) 
“As Ficker (1903, p. 274) properly points out, 
Celli’s statement has less value to-day, since at the time 
he carried out his experiments no suitable means ex¬ 
isted for properly differentiating B. typhosus from 
other organisms of similar character. 
“Firth and Horrocks (1902) kept M. domestica 
(also blue-bottles) in a large box measuring four by 
three feet, with one side made of glass. They were 
fed on material contaminated with cultures of B. 
typhosus. Agar plates, litmus, glucose broth, and a 
sheet of clean paper were at the same time exposed in 
the box. After a few days the plates and broth were 
removed and incubated with a positive result. The 
flies’ excreta on the paper yielded B. coli almost in pure 
culture. In a second experiment some fresh typhoid 
stool to which a typhoid culture had been added was 
dusted with earth and served as the infective material; 
colonies of B. typhosus appeared on the plates. In a 
