ii2 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
nor extensive enough to warrant any large general deductions. The results were 
uniform enough, however, to be summarized as follows : — 
1. The motility of B. typhosus is enough greater than that of B. coli, so that 
if infected material be introduced into the bottom of sterile tubes, temporarily con- 
fined there, and then liberated into a long column of fluid, preferably a viscid one, 
B. typhosus will regularly rise to the surface first, and can there be readily isolated, 
often in pure culture. 
2. The presence of sodium taurocholate in the fluid used arrests the activity 
and development of organisms other than intestinal, especially if incubation be at 42° C. 
3. If non-intestinal organisms are thus suppressed, and the medium be free 
from sugar, the presence of B. coli will, probably, not interfere with the development 
and detection of B. typhosus, in case the latter be present. 
4. It seems likely that if to fairly large quantities of suspected water there be 
added a small percentage of peptone, or other suitable sugar-free nutrient medium, as 
well as a concentrated solution of bile-salt, and the mixture be incubated for twenty- 
four hours at 42 0 C, the chances of isolating B. typhosus will be greatly increased. 
September, 1902 
