For, although a few cases of small-pox occurred
in instances where vaccination had taken place,
it was believed that such cases were the result
of imperfect vaccination, of the appearance of
what was called false vaccine, or of an interruption
in the course of the development of the
cow-pox by pressure on the pustules. .

So entire was the belief during these years of
the unfailing result of the operation, that much
surprise was excited by an account of the
appearance of an undoubted case of vaccine in a
person who had previously been successfully
vaccinated, and whose arms bore unmistakable
marks that the cow-pox had, what is popularly
called, taken.  This case was cited by a well-
known French physician, Monsieur Rayer, in
1825, as being a most extraordinary and
unprecedented instance of a second development of
cow-pox: it being supposed that the reappearance
of that malady, after successful vaccination,
was as impossible as the breaking out of smallpox
under similar conditions.  The case, however,
being then an isolated one, the excitement
caused by its appearance seems to have died
away, and people returned to their former
convictions. Some years later, however, new facts
arose to dispel this assurance of security, for,
in Glasgow, several instances appeared, nearly at
the same time, of small-pox in persons duly
vaccinated.

The experiment of re-vaccination was then,
for the first time, attempted, and as in many
instances it produced a return of cow-pox;
the question raised by M. Rayer was solved;
and it was supposed that the repetition of the
operation at certain intervals, or whenever the
malady appeared in the form of an epidemic,
would prove an effectual security.  If the
cow-pox were duly re-developed, the partisans
of the system argued, there was complete
hindrance to any attacks of small-pox; if the
former failed to appear, it proved that the
system was proof against the invasion of the
latter.

But, further experience demonstrated that
this idea was also a fallacy.  In Paris and
elsewhere, during the last ten or twelve years,
frequent instances have occurred of persons who,
having been re-vaccinated several times without
success (vaccination having proved effectual
in their childhood), were supposed not to be
liable to small-pox, but who were yet seized
with the malady, and that sometimes in its
worst form.  Moreover, the question, long held
in abeyance, as to the possibility of the
communication of disease through vaccination, was
again brought forward, certain facts tending
to give colour to such a theory having been
observed.

Dr. de Paul, director of vaccination at Paris,
in his last annual report to the Minister of the
Interior, adduced various instances where
dangerous maladies had been communicated from
unhealthy children to those born healthy, and
of parents free from taint.  And in England,
within the last two years, during which period
the small-pox has in several places proved severe,
re-vaccination, on adults especially, has been
sometimes attended with very serious
consequences, leading to the inference that the virus
was of an injurious nature.

All these circumstances taken into consideration,
one conclusion became evident —namely,
that an attempt must be made to return to the
original source.  The complete efficacy of the
natural vaccine, not only when taken direct
from the cow, but even for a certain time after
its transmission through the human subject, had
been proved by undoubted evidence; the
impossibility of its being mistaken for any other
affection, and its perfect freedom from the danger of
introducing contamination into healthy blood,
had been equally clearly demonstrated; and,
though some still obstinately adhered to the
belief that vaccination lost nothing of its efficacy
by the usual method, and was free from
the evils it was accused of producing, men of
intelligence and energy resolved to recommence
the experiments of Jenner, persuaded of the
necessity of re-establishing the purity of the
virus, and doubting nothing of producing similar
results by similar means.

A Neapolitan physician was the first to carry
into effect these conclusions.  Dr. Negri
established, near Naples, a collection of heifers, to
which he communicated at different periods the
cow-pox from a cow sent over by the Queen
from England in 1857.  From these he vaccinated
and re-vaccinated many thousands of
persons with the most satisfactory results, and
medical men and savans visited the institution
to study the system and report on its effects.
France soon followed the example.

Dr. Lanoix, having, on the spot, obtained all
the necessary information, took back to France
a cow affected with cow-pox, and brought
together at Bel-Air a number of heifers on the
same plan as that of Dr. Negri.  He commenced
operations by re-vaccinating all the pupils of
the school of the Prince Imperial at Vanves,
and, in the majority of instances, the vaccination
took perfectly, showing how ineffectual the
first operation, performed by the old system,
had been.

Belgium followed.  A physician of Brussels,
studying the question under M. Lanoix, and
obtaining from him sufficient virus to perform
a large number of operations —attended in most
cases with the same results as those witnessed
in Italy and France —appealed to the communal
administration for a vote of funds to
set on foot a public establishment to carry out
a system so important to the public health.
The application was attended with success, and
money has been granted for the foundation of
what is called an Etablissement Vaccinogène at
Brussels.

Surely England, where the discovery was first
made, and which supplied the means of
re-establishing the purity of the preservative matter,
should not remain behindhand in the race!  The
frequency with which small-pox has displayed
itself in England of late years, the severity not
unfrequently attending the cases, and the by no