16 
] 
These results plalnl}" show that the plague bacillus will live a long 
time in water containing a trace of albuminous matter — there were 
four drops of bouillon to 15 c. c. of water. 
The influence of temperature is very marked in these tests, for the ' 
organism lived only six days at 37° C., whereas it lived one hundred 
and sixteen days at 17° to 19° C. It will also be noticed that it lived 
longer at 17° to 19° than at 22° to 29° C. That is, the cooler the 
temperature the better does the organism resist. 
It is of special importance to notice that the bacillus sometimes lost 
its virulence in water before it lost its power of veg’etation. 
PLAGUE ON PAPER. 
I 
It was found that plague will not live very long on paper, even when 
in the presence of moisture. It usually died out in a few da^^s, except- | 
ing when kept cool at 17° to 19° C., at which temperature it remained 
alive eight and fourteen da}"s. It would appear from these experi- , 
ments that letter mail is not apt to carry the infection, especially in 
hot weather. 
Small slips of white filter paper were inoculated with a three-day- 
old bouillon culture of the bacillus pestis and placed in a Petri dish 
under the following conditions: 
Xo. 9. — Bouillon Cultuke on Papee, 37° C. ' 
Time. 
Result. 
Remarks. 
2 da vs 
4 davs 
- 
6 davs 
8 davs 
10 davs 
12 davs 
Contaminated with a sarcina. 
14 davs 
Xo. 10. — Bouillon Cultuke on Paper, 17° to 19° C. 
Time. 
Result. 
Remarks. 
2 davs 

4 davs 
- 
Contaminated with a long rod. 
6 days 
- 
8 davs 
— 
10 davs 
— 
12 davs 
— 
14 davs 
_ 
Xo, 11. — Bouillon Culture on Filter Paper, 17° to 19° C. - 
Time. 
Result. 
Remarks. 
3 davs 
4- 
The slips are dry. Delayed growth. 
8 davs 
+ 
14 davs 
Contaminated with a mould. 
2b davs 
