DETECTION OF B. TYPHOSUS IN INFECTED MATERIAL in 
Koch 7 for the easier isolation of cholera vibrios from stools, led to the following 
preliminary experiment* : — 
Experiment 5. Three flasks A, B, and C were inoculated as follows : — 
Flask A 
Flask B 
Flask C 
Water, 2,000 c.c. 
B. typhosus, 1 loop. 
1,000 
Water, 2,000 c.c. 
B. typhosus, 1 loop. 
1,000 
Peptone, 10 grammes. 
Water, 2,000 c.c. 
B. typhosus, 1 loop. 
1 ,000 
Peptone, io - o grammes. 
Sodium taurocholate, IO'O grammes 
Remarks. Tap-water was used. One loop of a sixteen-hour bouillon culture 
of B. typhosus was inoculated into 100 c.c. of sterile water, and cr 1 c.c. of the mixture 
introduced into each flask. I he peptone (Witte's) was introduced in concentrated 
solution and the same was done with the sodium, taurocholate. 
The three flasks were placed together in the thermostat at 42 0 C. Two things 
were to be determined : (1) Whether the number of organisms was markedly greater 
in Flask B than in Flask A. (2) Whether the bile-salt prevented the growth of 
organisms other than in B. typhosus (Liverpool tap-water being daily shown to be free 
from B. coli) ; also, whether the introduction of the bile-salt apparently inhibited 
B. typhosus, so that there were less colonies of it on plates made from Flask C than 
on those made from Flask B. 
After twenty-two hours' incubation, gelatin plates were made from each flask, 
o - i c.c. of the fluid being added to each plate. The writer was obliged to bring the 
experiments abruptly to a close before exhaustive determinations of the results could 
be made. After forty-eight hours' incubation, however, the plates showed the 
following results : — 
Plates from Flask B showed a far greater number of colonies than those from 
Flask A. 
Plates from Flask C showed less colonies than from Flask B. This was to 
be expected, because of the bile-salt in Flask C. Time did not suffice to determine 
whether the number of colonies of B. typhosus on plates from Flask C was less than 
that on plates from Flask B. Sub-cultures made from the colonies of the former 
proved them to be without exception, however, those of B. typhosus. 
In conclusion. The experiments here reported are neither numerous enough 
* Experiments conducted by Vau^han 11 showed that, by incubation at high temperatures, water organisms could 
be excluded. 
