5 
The little balls soon dry and the gelatin-albumin shrinks to a flaky, 
dry, hard mass. 
From time to 'time one of the dried balls is taken out, planted in 
bouillon, and incubated. In case a growth appears the organism is 
tested on all the media, and on mice. 
It was found that the organism lived and remained virulent for mice 
under these conditions for seventy-five days in the dark room at about 
20° to 23° C. and for seventy-five days in the cool chamber at 17° to 
19° C. Whether it may live longer will be determined from time to 
time and reported later on. 
CRASH INFECTED WITH PLAGUE CULTURE. 
In another series of experiments little squares of fabric (crash) were 
sterilized and inoculated with a three-day-old bouillon culture of the 
bacillus pestis. One set of these was allowed to dry out in Petri dishes 
in a dark corner of the laboratory where the temperature ranges from 
about 20° to 27° C., another set in the cool chamber (17° to 19° C.), and 
another set in the photographic dark room (20° to 23° 0.). The squares 
were removed at intervals and planted in bouillon and in case a growth 
appeared it was studied for purity and pathogenicity in media and mice. 
The following are some of the results : 
Bouillon culture on crash. 
Time. 
Laboratory 
20° to 27° C., 
Cool chamber, 17° to 19° C. 
Dark room, 20° to 23° C. 
4 days.. 
+ 
+ 
-f 
8 days 
— 
+ 
-U 
11 days 
+ 
— 
— 
13 days 
+ 
+ 
+ 
15 days 
— 
— 
-f- 
21 days 
. 
+ Killed mouse in two days. 
+ Killed mouse in two days. 
26 days 
— 
— 
+ Killed mouse in three days . 
35 days.... 
— 
+ 
+ 
48 days 
— 
+ Killed mouse in three days. 
+ Killed mouse in two days. 
From this table it appears that the organism died after thirteen days 
when kept at a temperature which occasionally rose to 27° C. 
At a somewhat lower temperature it remained alive and virulent 
forty-eight days. Whether longer, will be reported upon the comple- 
tion of the work. This table iodicates plainly how sensitive this par- 
ticular organism is to a very slight difference of temperature. 
PINE WOOD INFECTED WITH PLAGUE CULTURE. 
Another series of tests was made with splinters of pine wood about 
the size of a match stick. _ They were sterilized and soaked in a three- 
day-old bouillon culture of plague and then placed in Petri dishes 
