8 
nately applied on the viability of the plague bacillus and found it to be 
more harmful than simple drying. He found that changing the condi- 
tions from dryness to moisture caused the death of the organism in 
twenty to twenty- eight hours, while the same in the desiccator lived 
eight or nine days. 
He used twenty-four hour old cultures from agar-agar plates and made 
thin spreads on cover glasses by means of the platinum cese. Moisture 
was added twice daily. The cover glass was planted in bouillon and in 
case growth aj^peared this was plated out on gelatin. 
Alternate 
moisture. 
Desiccator. 
t 
0 
-f 
0 
Culture 24 hours 
Do 
Culture 36 hours 
Hours. 
20 
24 
36 
Hours. 
28 
36 
48 
Days. 
8 
9 
11 
Days. 
9 
11 
12 
This demonstrates that cultures die more rapidly in drying when 
moisture and dryness are alternated. 
Batzaroff (a) has been able to demonstrate that even in the dry 
state the pest organism remains living and virulent a long time. The 
organs of an animal dead of pest, as well as cultures mixed with infus- 
orial earth, are subjected to desiccation in vacuo at “ room temperature.’^ 
From time to time a piece of the dried substance is tested by grinding 
in a sterilized mortar, and the x>owder thus obtained is introduced 
in small amounts into the nose of an animal. The results of these 
experiments, which are indicated in the subjoined table, show that the 
virus of pest supports desiccation for a long time very well when it is 
in an albuminous medium, as the pulp of the spleen or any other organ. 
Under such conditions it attenuates very slowly; in fact, in the first 
two or three weeks scarcely at all. On the other hand, if it is not i^ro- 
tected, as in the case of dried cultures in infusorial earth, its virulence 
diminishes rapidly, so that in three weeks, inoculated into the nose of 
animals, the dried cultures produced no morbid effect. 
Plague-jmeumonia produced by nasal inomlations of dried virus. 
Splenic pulp. 
Dried cultures in infusorial earth. 
Duration of desiccation. 
Duration 
of sickness. 
Duration of desiccation. 
Duration 
of sickness. 
Days. 
Days. 
5 davs 
^V2 
2 days 
8 davs 
4 
5 davs 
634 
12 davs 
7 days 
(6) 
14 davs 
5 
19 days 
12 
20 davs 
4H 
31 davs 
d>) 
26 davs 
30 davs 
i 6K 
33 days 
1 634 
38 days 
: 634 
i 
44 davs 
: (ft) 
a La Pneumonie pesteuse experimentale. Annales de I’lnstitut Pasteur, May, 1899, page 392. 
6 Resisted. 
