10 
stances such as sponge we found it alive after one hundred and twenty- 
five days, when allowed to dry, at 19° C. Here again temperature 
pla 3 ^s an important role, for at 37° C., all the other conditions being the 
same, it lived only two days. 
It is therefore veiy unlikel}^ that new merchandise would be so 
contaminated as to carry the infection of the disease, especially in hot 
weather. 
PLAGUE IN CLOTHING AND BEDDING. 
The bacillus of plague lives long in albuminous matter. Clothing 
and bedding are especially apt to be contaminated with the discharges 
from buboes and blisters, sputum, etc. Articles so infected and kept 
in a cool, moist place could retain the active infective principle a 
very long time. Our work shows plainly that clothing and bedding 
may harbor the bacillus of plague for months. In one instance we 
kept it alive on a piece of crash ninety-seven days; in albumin gela- 
tin balls one hundred and twenty-live days; in sponge, also, one hun- 
dred and twenty-live days; in wool lifty-two days. 
PLAGUE IN THE MAIL. 
According to our results the plague bacillus can not live long in let- 
ter mail. In seven tests made with cultures of the organism on paper 
we found that it usually died within twenty-four hours. At most it 
kept alive eight days on paper allowed to dry, and fourteen da}^s on 
paper kept in a moist atmosphere. To live this long it must be kept 
cool, for, just as in all our other experiments, it died very quickly 
when dried at the body temperature. We had similar experiences 
with plague blood upon paper. Letter mail is therefore not apt to 
carry the infection of plague a long time, especially in warm weather. 
VIABILITY AND VIKULENCE. 
The bacillus pestis often loses its virulence before it dies. In many 
of our experiments we found that the time came when the organism 
grew in bouillon, but lost its pathogenity for animals. This is an 
important fact from an epidemiologic standpoint, for an attenuated 
plague bacillus is probably harmless to man, even though its virulence 
can be increased by artificial means in the laboratory. 
GASEOUS DISINFECTANTS FOR THE PLAGUE BACILLUS. 
The experiments conducted in this laboratory plainly prove that 
either sulphur dioxide, when moist, or formaldehyde will kill the 
bacillus pestis when applied in the strength and methods usually 
employed for these gases as disinfecting agents. In order to be effect- 
ive there must be direct contact between the gas and the germ. In 
other words, these gaseous clisinfectants can onH be depended upon as 
surface disinfectants. 
