Pathogenic Bacteria

CHOLERA. 325

necrosis and perhaps death. Protection certainly seems
to follow the operation of these vaccines.

Haffkine's studies embrace more than 40,000 inocula-
tions performed in India. From his latest paper (Dec.,
1895) the following extract will show the results:

"i. In all those instances where cholera has made a
large number of victims, that is to say, where it has
spread sufficiently to make it probable that the whole
population, inoculated and uninoculated, were equally
exposed to the infection,—in all these places the results
appeared favorable to inoculation.

U2. The treatment applied after an epidemic actually
breaks out tends to reduce the mortality even during the
time which is claimed for producing the full effect of the
operation. In the Goya Garl, where weak doses of a
relatively weak vaccine had been applied, this reduction
was to half the number of deaths ; in the coolies of the
Assam-Burniah survey-party, where, as far as I can gather
from my preliminary information, strong doses have been
applied, the number of deaths was reduced to one-seventh.
This fact would justify the application of the method in-
dependently of the question as to the exact length of time
during which the effect of this vaccination lasts.

" 3. In Lucknow, where the experiment was made on
small doses of weak vaccines, a difference in cases and
deaths was still noticeable in favor of the inoculated
fourteen to fifteen months after vaccination in an epidemic
of exceptional virulence. This makes it probable that a
protective effect could be obtained even for long periods
of time if larger doses of a stronger vaccine were used.

" 4. The best results seem to be obtained from applica-
tion of middle doses of both anticholera vaccines, the
second one being kept at the highest possible degree of
virulence obtainable.

"5. The most prolonged observations on the effect of
middle doses were made in Calcutta, where the mortality
from the eleventh up to the four hundred and fifty-ninth
day after vaccination was, among the inoculated, 17.24