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MANUAL OF VACCINATION FOR THE
incapable afterwards of contracting small-pox. The process of inserting the
lymph from arm to arm, or from calf to arm, is called vaccination, and if the
resulting vesicle rises properly, the person is said to have been successfully
vaccinated, or to have had modified cow-pox (vaccinia). As mentioned
above, vaccinia is small-pox deprived of its virulence by transmission
through the cow. So thoroughly and with such industry did Jenner follow
out his discovery that in the year 1801 he writes: " Upwards of 6,000 persons
have been inoculated with the virus of cow-pox, and the far greater part of
them has since been inoculated with that of small-pox and exposed to its
infection in every rational way that could be devised, but without effect."
From this time onwards the spread of the practice of vaccination was
rapid, and wherever it spread the prevalence of small-pox decreased. At
the present day, in most civilized countries, vaccination is enforced by law and
small-pox is rarely seen. Thus Germany, with a population of six hundred
lakhs, shows less than a dozen deaths from small-pox in a year. For this
remarkable discovery and its subsequent application, Parliament voted
Jenner a lakh of rupees;but no money reward can adequately recompense a
man who conferred such an inestimable benefit on suffering humanity.
Spread of vaccination.
4. The fame of this discovery soon became known throughout the whole
civilized world, and before many years were over, vaccination was almost
universally practised by all classes of people. As a consequence, where for-
merly thousands used to be carried off annually by small-pox, now the
disease is comparatively rare.
So very safe in its application and so generally successful in its object
was vaccination, that its performance was soon recognised as a necessity,
and compulsory vaccination was introduced into all civilized countries.
Vaccination does not, and Jenner did not pretend that it would, protect
absolutely from small-pox. Even an attack of small-pox by ordinary con-
tagion does not absolutely protect. But vaccination does ordinarily protect,
and an attack of small-pox does generally render the individual insusceptible
to a second attack. During an epidemic at Sheffield in England in 1887, it
was found that of children under five years of age who were unvaccinated,
no less than 1 in 10 caught small-pox, while among the vaccinated only 1 in
200 contracted it. If the mortality from the disease is considered, the results
are even more convincing. During the same epidemic at Sheffield, it was
found that no less than 37 died in every 100 among those who were unvacci-
nated, while only 1 in 100 died in those that were vaccinated. These are
matters of general knowledge, and have been verified again and again all
over the world.
Incidence with regard to sex, age, and race.
5. It has been noted, and statistics have confirmed the fact, that the
mortality from small-pox is greater among males than females, and among
dark races than fair. In pre-vaccination times, as MacVail has shown from
the Kilmarnock registers, 90 per cent. of the deaths were at ages below five,
the actual maximum being at the second year. For the above reasons it is,
therefore, very necessary for the people of this country to have their children
vaccinated, and preferably during the first year of their life. Very few
children are insusceptible to vaccination—probably not one in 30,000 ; but
not less than two attempts should be made to vaccinate a child.
Protective power of cow-pox and revaccination.
6. Vaccination is protective against itself as well as against small-pox.
All experience goes to show that the period of absolute protection is