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among records of old date, but represent occurrences which have taken place, one during
the vaccinating season just passed, and the other in the preceding one. They represent not
what was in India in times past, but what exists at the present day.
Is vaccinia in India protective ?
7. We may consider now the question in a narrower form, and enquire whether vaccinia
is really protective in India. It is as yet impossible
to adduce proof in a statistical form in support of
vaccinia being protective. During the small-pox epidemic in Calcutta in 1864 as well as on
previous occasions, the fact that numbers who had been vaccinated had been exposed in the most
prolonged and careless manner to contagion, without contracting the disease, is however a
very striking one.
Under these circumstances, large numbers were found to be exempted from small-pox by
previous vaccination, and when they did contract the disease in the great majority of instances
they had it in a mild form. Even when the eruption was abundant, the danger to life from post-
vaccinal small-pox was found to be very slight indeed. The exact degree in which failure of
protection existed may be judged of by the revaccination test to be presently detailed, and is in
no way the fault of the vaccinia. During the months in which the epidemic was at its height,
thirteen thousand re-vaccinations were practised. Had there been any imperfection in the
protective power of the virus, many of these cases would have been found to contract
small-pox in spite of the use of the prophylactic. In some the disease was incubating before
the vaccination was practised, and these got the disease modified or not by the vaccination,
according to the length of time which had elapsed between the reception of the contagion
and the vaccination. After the vaccination had run its course, I do not know an instance
of one single individual having been attacked by small-pox.
After children had been vaccinated, they have been subjected to the test of inoculation;
I do not know of a single case in which it was possible to infect them under these
circumstances.
Is vaccinia in India as protective against small-
pox as inoculation is ?
8. It is not sufficient simply to establish the fact that vaccination is protective, but it
must be shewn to be as efficacious as inoculation
against small-pox. The immunity enjoyed by those
who have gone through one attack of small-pox from
a repetition of the disease is relative and not absolute. In certain races, such as the Goorkhas
and other Hill tribes, instances of severe attacks of small-pox for a second or third time are
much more common than among European nations. The exact liability of the Bengallee to
such subsequent attacks of small-pox is not known, though the fact that they are liable is
certain. It is extremely difficult to collect statistical data on this point. A similar difficulty
exists when an attempt is made to obtain precise information regarding the liability to small-
pox after inoculation and vaccination.
Vaccinia is only a modified small-pox, which results on the use of that cultivated small-pox
virus which is called vaccine. By applying the test of vaccination, the exact amount of
liability to small-pox can be ascertained. The test is a more searching one than mere exposure
to infection, and hence the protection found defective by vaccination might still have served
to guard against the lesser degrees of contagion consequent on simple exposure to the influence
of a case of small-pox. In 1864 this test was applied to large numbers of persons in
Calcutta; persons who had previously suffered from small-pox, those who had been already
inoculated, and those who had been vaccinated, were subjected to the test. In each of the
three classes the results obtained from the vaccination were surprisingly uniform. The
deduction was irresistible, that the protection afforded by the previous attack was the same,
whether it had been of spontaneous origin, had followed on inoculation, or had been
communicated in the form of vaccinia.
Question of vaccination versus inoculation.
9. When the result has been arrived at, that vaccination is as protective as inoculation,
the question of the respective merits of the two is a
very simple one indeed. Connected with the practice of
small-pox inoculation, there is the direct as well as the indirect mortality already considered,
which though it may be small still always exists; when the disease has been produced in a severe
form, you have besides this all the suffering connected with a spontaneous attack of small-pox, as
well as disfigurement, lameness and blindness, which may also ensue; and besides, those
undergoing inoculation have to subject themselves besides to several restrictions. With the
practice of vaccination no such drawbacks and disadvantages as those above enumerated are
associated.