SBS Roberg: Bacterial Infections 817 
Bacteria introduced into the intestinal tract of flies are passed 
in the feces, living and virulent, and contaminate the surface of 
the eggs as they are laid. 
The pathogenic bacteria occurring in meat also occur in the 
intestine of larve feeding thereon. 
Pathogenic bacteria occurring in the pupa are transmitted 
to the imago which in turn disseminates infection in its feeces. 
In 1909 Faichnie,(26) following Cao’s suggestions, used Bacil- 
lus typhosus. His procedure was as follows: 
Into a box of earth containing three ounces of feces, infected 
with typhoid bacilli, 30 flies were let loose and covered with a 
wire gauze. In a day or two all these flies died, but fourteen 
days later 1 fly emerged. On the fifteenth day 12 more emerged. 
On this day the box was replaced by an earthenware dish washed 
in bichloride of mercury, and water and sugar were intro- 
duced as food and covered. ; 
The 1-day-old fly was transfixed with a red-hot needle, flamed 
and washed in 1 cubic centimeter of sterile salt solution, part 
of which was inoculated into McConkey’s broth, which remained 
unchanged for forty-eight hours. This same fly, when crushed 
in sterile salt solution and a drop plated, showed the presence 
of typhoid bacilli. Four other 1-day-old flies gave identical 
results. 
Two flies 6 days old and two 9 days old gave the same results. 
Two flies 13 days old showed feces infected with B. typhosus. 
One fly 16 days old showed typhoid-contaminated feces; when 
crushed it showed the same contamination. 
Faichnie concludes that of 18 flies bred from a typhoid stool 
at least 6 contained the bacillus in the intestines and that a 
16-day-old fly contained bacilli both in the intestines and feces. 
The results described by Faichnie are to be questioned, be- 
cause there is no evidence in his paper that the larve fed on 
the infective material were separated from the pupz or newly 
emerged adult flies. There is no evidence to exclude the pos- 
sibility that the emerging adults were not reinfected by feeding 
on the typhoid feces. (The species of flies used are not men- 
tioned.) 
In considering later the work done by Ledingham, it will 
appear remarkable that the typhoid bacilli in the feces remained 
capable of infecting the flies for a period of twenty days. In 
Ledingham’s paper it will be further pointed out that typhoid 
