10 
sputum from plague-pneumonia. 
Object. 
Temperature. 
Longest 
time in 
days the 
organism 
lived. 
Glass 
30° to 32° C. 
1 
Silk thread 
3 
Piece of wool 
do 
6 
Pus from bubo. 
Glass 
Silk thread .... 
Piece of wool, 
30° to 32° C. 
.. ..do 
do 
6 
1 
1 
Peritoneal exudate from plague-infected guinea pig. 
Silk thread 
Filter paper 
29^ to 31° C. 
do 
Piece of silk 
do 
(a) 
Piece of wool 
do 
Glass tube 
do 
(ft) 
a still virulent on the second day. 6 Dead on the seventh day. 
The loDgest observation made by the commission on the viability of 
the plague bacillus was therefore eight days. 
It made no difference whether cultures one to two days’ old, or eight- 
day-old cultures were used, as far as the resistance to drying was 
concerned. 
Pieces of the skin of mice dead of plague were also kept and it was 
found that they had lost their infectiug power after four and six days. 
In dry organs the pest bacillus soon died. The longest time observed 
was in pieces of liver kept in sealed glass tubes. Here they lived seven 
days ; after seven days no result was obtained. 
Sterilized feces were inoculated with a bouillon culture of plague 
obtained fresh from a corpse and then saturated with silk threads, wool, 
and silk fabrics. After drying they were wrapped in sterile filter paper 
and, inclosed in cotton, were packed in a box and kept in the laboratory 
at about 29° C. After four days the pest bacillus was alive on all the 
test objects ; after six days only in the wool, and after eight days dead 
in all. 
The energetic drying in the desiccator over sulphuric acid hastened 
the death of the organism. 
On account of the great importance of this question, several more 
tests were made, at lower temperatures, by the committee after its return 
to Germany. It was there possible, on account of the more favorable 
laboratory conditions, to make cultures as well as inoculations into mice 
in order to establish the life and death of the bacillus. The bacillus 
was kept alive in a room at 15° to 18° 0. for twenty- eight days. After 
thirty-three days no more grawth was obtained. Even after twenty- 
four days the growth was very sparse. The pathogenicity for mice died 
out much quicker after eighteen days. 
