1901] MICROSCOPICAL JOURNAL. 187 
2 Temperature is the most important factor in the vi- 
ability of the plague bacillus. It keeps alive in the cold, 
under 19° O,, a very long time. It dies quickly, especi- 
ally when dried, at the body temperature, 37° C. 
3 Moisture favors the life of the bacillus pestis. It 
usually dies in a few days when dry, evenin the presence 
of albuminous matter, provided the temperature is above 
30° C. It may keep alive and virulent when dry for months . 
in the cold, under 19° C. 
4 Sunlight kills the organism within afew hours, pro- 
vided the sun shines directly upon the organism and the 
temperature in the sun is over 30° C. The effect of sun- 
light is not very penetrating. 
5 The virulence of the bacillus pestis is often lost be- 
fore its vegetability. 
6 It is unlikely that new dry merchandise would car- 
ry the infection. The organism usually dies in a few days 
on the surface of objects such as wood, sawdust, bone, etc. 
7 Clothing and bedding can harbor the infection for 
a long time and may act as fomites. The bacillus lives 
for months when dry in albuminous media at tempera- 
tures under 20° C. 
8 Food products may carry the infection of plague. 
The bacillus lives a long time in milk, cheese, and butter. 
It usually dies quickly on the surface of fruits and per- 
pared food. 
- 9 The organism may live a long time in water, al- 
though plague is not a water-borne disease, 
10 The plague bacillus does not live long on paper, 
and first-class mail is therefore not apt to convey the in- 
fection. 
11 The colder the climate the greater the danger of 
conveying the infection on fomites—clothing, bedding, 
food, merchandise, etc.—and. more extensive disinfection 
is required in such a climate in combating the disease than 
in tropical regions. 
