UNITED PROVINCES OF AGRA AND OUDH.
3
limited, and that sooner or later the degree of protection in a vaccinated
person becomes diminished. But the bulk of experience incontestable
proves, that a person even once vaccinated, usually escapes small-pox or
only takes it very mildly. The degree of protection is directly pro-
portionate to the number or size of the marks. From this we learn
two facts—that the marks when few in number should be good ones,
and that revaccination after eight or 10 years is desirable. During an
outbreak of small-pox if the person has been exposed to infection, the disease
will be superseded or not according to the time which has elapsed before
vaccination—that is to say, if the patient is vaccinated within three days
after taking the contagion, the vaccination, which takes eight or nine days to
develop, will have the start (for the poison of small-pox lies latent in the
system for 12 days) and the vaccine vesicle will have had time for full
development Hence the variolous disease will be suppressed. But if the
operation is not performed until after the third or fourth day of exposure,
the small-pox virus will have had time to mature and will not be arrested,
(although modified), the two diseases running concurrently. If performed
at a later date than that above given, the vaccine virus will have no effect.
(Small-pox in India is often by the natives confounded with lichen, febricula,
varicella, rubeola, roseola, and sudamina). Hence it will be noted, persons
successfully vaccinated in infancy, should be again vaccinated about the age
of puberty, as at that age a change in the constitution has taken place, and it
is therefore desirable to ascertain if the protection conferred in infancy is
still effective.
Secondary vaccination should be practised at all ages when the cicatrices
of the original vaccination are too few in number or not deeply marked—as
in cases with a single mark (one mark cases). It should be practised also
on those who have had an attack of small-pox naturally or by inoculation,
when the pitting is at all indistinct.
On revaccination one of three results ensues—
(1) the result is negative, showing perfect protection ;
(2) a modified pock appears about fifth day and the scab falls off a
day or two later; and
(3) a perfect pock appears, showing that protection was only very
slight.
In Germany re-vaccination was made compulsory in 1874, with the result
that small-pox epidemics have been abolished altogether. The rate is almost
nil, and the few cases that occur are due chiefly to importation.
Objections which have been urged against vaccination.
7. The opponents of vaccination have said that cow-pox, being a differ-
ent disease from small-pox, cannot possibly protect from small-pox. The
numerous recorded results of epidemics which have shown the vastly greater
safety enjoyed by the vaccinated, are a sufficient answer to this objection.
It is, however, now certain that cow-pox is not a different disease, but is
simply small-pox modified by passage through the body of the cow. As long
ago as 1840 (see paragraph 2), Ceely and Badcock proved this by experi-
ment. They inoculated a cow with the virus taken from a case of small-pox
in a human being. The cow developed typical cow-pox and was afterwards
shown to be protected against the cow-pox virus. Other cows inoculated
from the first cow reproduced the appearances of cow-pox, and human beings
inoculated from one of these animals showed the ordinary appearances of
successful vaccination. This change in the character of a disease produced
by passage through another animal is not an isolated instance: thus the