30 Description of Plague: [ CHAP. II.
In pursuance of this view Mr. Hankin made a series of interesting
experiments on the floors of houses, which are described in Chapter
VIII in dealing with the subject of disinfection, and which are repro-
duced in Appendix VI.
Vitality of
bacillus in
food-stuffs and
dead bodies from
point of view of
susceptibility to
action of organic
acids.
Mr. Hankin made the following interesting deductions regarding
the vitality of the bacilli in food-stuffs and dead bodies from its sus-
ceptibility to the action of organic acids:-
"In view of the fact that most articles of diet either possess an
acid reaction or rapidly acquire it on the onset of decomposition owing
to the appearance of the above acids or their allies, it seems scarcely
probable that food-stuffs should retain for long the microbe of bubonic
plague. In the case of milk this speculation has been put to an
extended test by Dr. Srinivasa Rau in my laboratory in Bombay. He
found that as soon as milk has been kept long enough to acquire a
well marked acid reaction, that is to say, within a few hours of milking
under ordinary conditions, it has the power of destroying the bubonic
microbe within an hour. If, on the other hand, the milk is made faintly
alkaline, it is incapable of so doing, and appears to be a good food
medium for the bubonic microbe. Dr. Rau has also carried out exper-
iments on the vitality of the bubonic microbe in rotten grain. This
substance nearly always has an acid reaction, and is then capable of
rapidly destroying the bubonic microbe. I propose to describe his
experiments at length in another report. The tissues of animals after
death acquire an acid reaction owing to the development of an ally of
lactic acid. Dr. Rohak under my direction has found that this acid
reaction appears in the bodies of animals dead of plague. This point,
though it has no bearing on the admitted danger of handling and
washing plague corpses, may, if worked out, be found to have an im-
portant bearing on the old idea that graveyards may be a lasting
source of infection. "
Mode in which the Bacillus enters the System.
Scheube.
Scheube states that infection can take place by the air or touch, and
consequently the poison may gain access to the body by the respira-
tory organs or by the skin.
Hong-kong
observers.
Among the observers of the Hong-kong plague Surgeon-Major
H. E. R. James states that the bacillus so far as is known gains access
by (a) respiration, (b) inoculation and (c) food. Staff Surgeon Wilm ex-
pressed the opinion that infection through the skin is not common; "for,
on the one hand, in the great majority of cases the buboes do not appear