4
CALCUTTA AND THE SUBURBS.
one large enough to cope successfully with small-pox—such large numbers of people still die
from this disease. I am the more anxious to year by year bring to notice that Calcutta is
still in a position of great danger from small-pox, as the danger is a progressingly increasing
one. After a great epidemic of small-pox, as when five thousand people die in one year of it,
the city is comparatively safe. Such large numbers of people have become protected, that by
comparatively easy means the rest can be kept in a state of safety. As year by year passes,
and thousands upon thousands of unprotected persons became mixed up in the community,
the danger again becomes great, and the difficulty immeasurably increases of keeping the
metropolis free from the disease.
8. Animal vaccination.—In my report in the year 1865 I mentioned that some trials
had been made to induce vaccinia in the cow, but had not succeeded. Subsequently it was
also reported that similar trials had failed. As animal vaccination was established last year
in Bombay, arrangements were made to have virus forwarded from that presidency direct
from the cow, so as to allow of calves being vaccinated in Calcutta. Just as on previous
occasions the " animal virus" had lost its infecting power during transmission when sent
from London and Paris, the first supplies from Bombay failed in producing the disease.
There can be no doubt that the virus itself had become inert, and that the calf, or mode of
operating, is no way to blame for the want of success. My own success on subsequent occa-
sions, and my having watched successful operators both in Paris and Lyons, would have been
sufficient to convince me of the correctness of the above statement; but an additional
evidence is derived from the fact that Dr. Pinkerton, the Superintendent-General of Vaccin-
ation in Bombay, who has successfully vaccinated in that presidency, failed in Calcutta
in securing a supply of vaccine from the virus procured from Bombay. To his dexterity
and care in operating I can bear abundant testimony. A supply of virus, dated 7th
February, was received in tubes from Bombay, and used on the 17th to vaccinate. Charac-
teristic vesicles resulted, and were used on the 25th to vaccinate another calf from; this also
succeeded, and the virus was transmitted from calf to calf without difficulty. Five calves
were thus successfully vaccinated. It is worthy of note that in no case, even when vaccin-
ating from calf to calf, did all the points of insertion take, so that unless it is afterwards
shown that such failures are in a measure due to preventable causes, should the experiment be
repeated, it will be necessary to make a greater number of points of insertion than the
number of vesicles wished for. The virus was used both by inserting it into punctures and
rubbing it over incisions. The successful points were almost entirely limited to the seat of
the punctures. Many of the vesicles were very typically perfect, and seemed identical with
the usual vesicles seen on the childs' arm. One great peculiarity noticed was that though
on examining the calf on one occasion, on the fifth or sixth day, not a single sign of success
was seen, on the next day perfect large vesicles were met with. In other cases a similar
apparent irregularity in developing the disease was noticed. Some of the calves used were
too young, and in one instance, owing to a difficulty in feeding the calf, it became very feeble,
and the vesicles were so flabby and badly filled, that I could not use the virus they contained
to vaccinate a child. The experiment is not an easy one to carry on in a town, as calves
cannot be got at the time they are wanted; they are very noisy, and for want of a special
servant to look after them, they are very troublesome. In the event of its ever being found
necessary to establish animal vaccination in Calcutta, such difficulties could be easily provided
against, as any permanent requirement can be easily arranged for.
As far as I can judge by this limited experiment, it seems quite easy to transmit the
disease from one calf to another, and I have no doubt I could without any difficulty teach a
vaccinator to do it, should it ever become necessary to do so. The tendency of the virus to
become inactive in a very short time in tubes makes it by no means easy to secure the
infection of the first calf. Though I am aware of the fact that many experimenters have
failed to keep up a continuous supply, I saw nothing in these experiments to lead me to think
that with good calves and ordinary care in selecting virus a continuous supply could not be
kept up.
9. Vaccination with animal virus —On the ground of losing caste none of the vaccinators
would open the vesicles on the calf and remove the virus contained in them. When the virus
was handed them on a lancet, they made no objection to vaccinating with it. After careful
inquiry it was judged expedient not to vaccinate publicly from the calf. Two children,
however, were vaccinated direct from the calf without the virus being stored in any way In
both the vaccination succeeded, and seven vesicles resulted from eight points of insertion.
The vaccination could in no way be distinguished from that obtainable from the virus in
ordinary use.
From these two children others were vaccinated, and the supply of virus thus obtained
has been kept up from arm to arm. I have seen these vaccinations as late as the twelfth