qually proof against the contagion and inoculation of vaccination and
variola, in spite of repeated attempts to secure both, while their
respective mothers suffered terribly with smallpox at periods
subsequent to the birth of their children; and it is well understood
that there are striking analogies between the poisons of certain
contagious fevers and those of venomous serpents, inasmuch as one
attack conveys exemption from future ones of like character. In other
words, many animal poisons, as well as the pathological ones of
smallpox, measles, scarlatina, whooping cough, etc., have the power of
so modifying the animal economy, when it does not succumb to their
primary influence, as to ever after render it all but proof against
them. Witness, for instance, the ravages of the mosquito, that in
certain districts punishes most terribly all new comers, and who after
a brief residence suffer little, the bite no longer producing pain or
swelling.

Regarding the supposed correlation of serpent poison and the septic
ferments of certain tropical and infectious fevers, they are not
necessarily always contagious. It may be interesting to note that one
Doctor Humboldt in 1852,[9] in an essay read before the Royal Academy
of Medical Sciences at Havana, assumed their proximate identity, and
advocated the inoculation of the poison of one as a prophylactic of
the other. He claimed to have personally inoculated numberless persons
in New Orleans, Vera Cruz, and Cuba with exceedingly dilute venom,
thereby securing them perfect immunity from yellow fever. Aside from
the extraordinary nature of the statement, the fact that the doctor
affirmed, he had never used the virus to an extent sufficient to
produce any of its toxic symptoms, cast discredit over the whole, and
proofs were demanded and promised. This was the last of the subject,
however, which soon passed into oblivion, though whether from failure
on the part of the medico to substantiate his assertions, or from the
inanition of his colleagues, it is difficult to determine, though the
presumption is largely in favor of the former. Nevertheless, it is
worthy of consideration and exhaustive experimentation, since it is no
less plausible than the theory which rendered the name of Jenner
famous.

[Footnote 9: London _Lancet_.]

Outside of the transfusion of blood, for which there are strong
reasons for believing would be attended with happy results, the sole
remedies available in se