short time. There are other varieties that retain their via})ility under 
similar conditions a long- time.'’ Bacteria show quite as strong a 
tendency to ada[)tability as the higher animals. They may become 
accustomed to influences by a gradual survival of the fittest so that 
they finally resist conditions that would be fatal to the parent stock. 
All these fax'ts must be borne in mind in drawing conclusions from 
laboratory experiments. 
PLAGUE AND FOOD. 
Our experiments show that food products mav harbor the infective 
principle of plague, but according to experience food products are not 
much to be feared as far as their probabilit}^ of carrying the infection 
is concerned. This latter statement does not apply to milk and its 
products, for milk is a good culture medium for the bacillus pestis; 
and we kept it alive seventeen days in cheese and seventy-two days in 
butter. 
On the surface of food products it usually died very quickly. It 
did not live twenty-four hours on orange peel. We had similar results 
with figs and raisins and a large quantity of Chinese food products, 
such as smoked and dried ducks, dried oysters, dried cuttle fish, dried 
ducks' gizzards, ducks' gizzards dried and placed in oil, smoked and 
dried pork, and duck eggs preserved in a mixture of mud and rice 
chaff, all of which were infected with the bacillus pestis and kept at 
37^ C. 
In rice we found it alive eighteen days after inoculating. 
These results correspond with all our other experiments, which plainly 
prove that the bacillus can not live long on the surface of objects, when 
dry, at temperatures al)ove 30° C. Those results are also in accordance 
with the clinical and pathological facts, for cases of plague that have 
their origin in the alimentary tract are comparative!}’ rare, and the 
spread of the disease has not, as far as I am aware, ever been clearly 
attributed to food products. 
Ilow’ever, tonsillar and intestinal forms of the disease have been 
recorded, and these cases may be due to the fact that the bacillus can 
live in milk, butter, and cheese, and similar moist albuminous media, 
as well as in water {vidt' infra) a long time. 
ei.AGUE AND WATEK. 
Plague is certainlv not a water-borne disease, although wi' tind that 
the plague bacillus can live a long time when abundantly inoculated 
into water containing a trace of organic matter. In on(‘ case we kept 
it alive one hundred and sixteen djiys, and in another nim'ty-six days, 
in water preserved at low temperatures, 17 to li* C. Puder the sanu' 
(‘onditions the organism liv(‘d onlv six da vs at 37"^ C. 
