istible faith, sweeping the invention out of
Jenner's hand and establishing it in a form which he himself repudiated.
Jenner was not a man of science; but he was not a fool; and when he
found that people who had suffered from cowpox either by contagion in
the milking shed or by vaccination, were not, as he had supposed, immune
from smallpox, he ascribed the cases of immunity which had formerly
misled him to a disease of the horse, which, perhaps because we do not
drink its milk and eat its flesh, is kept at a greater distance in our
imagination than our foster mother the cow. At all events, the public,
which had been boundlessly credulous about the cow, would not have the
horse on any terms; and to this day the law which prescribes Jennerian
vaccination is carried out with an anti-Jennerian inoculation because
the public would have it so in spite of Jenner. All the grossest lies
and superstitions which have disgraced the vaccination craze were taught
to the doctors by the public. It was not the doctors who first began to
declare that all our old men remember the time when almost every face
they saw in the street was horribly pitted with smallpox, and that all
this disfigurement has vanished since the introduction of vaccination.
Jenner himself alluded to this imaginary phenomenon before the
introduction of vaccination, and attributed it to the older practice
of smallpox inoculation, by which Voltaire, Catherine II. and Lady
Mary Wortley Montagu so confidently expected to see the disease made
harmless. It was not Jenner who set people declaring that smallpox, if
not abolished by vaccination, had at least been made much milder: on the
contrary, he recorded a pre-vaccination epidemic in which none of the
persons attacked went to bed or considered themselves as seriously ill.
Neither Jenner, nor any other doctor ever, as far as I know, inculcated
the popular notion that everybody got smallpox as a matter of course
before vaccination was invented. That doctors get infected with these
delusions, and are in their unprofessional capacity as members of the
public subject to them like other men, is true; but if we had to decide
whether vaccination was first forced on the public by the doctors or on
the doctors by the public, we should have to decide against the public.

STATISTICAL ILLUSIONS

Public ignorance of the laws of evidence and of statistics can hardly
be exaggerated. There may be a doctor here and there who in dea