ich
has found lodgment on the skin, and has burrowed and made itself at home
there. Kill that insect and the disease is no more; hence it has come to
be an axiom with the modern physician that the itch is one of the three
or four diseases that he positively is able to cure, and that very
speedily. But it was far otherwise with the physicians of the first
third of our century, because to them the cause of the disease was an
absolute mystery.

It is true that here and there a physician had claimed to find an insect
lodged in the skin of a sufferer from itch, and two or three times the
claim had been made that this was the cause of the malady, but such
views were quite ignored by the general profession, and in 1833 it was
stated in an authoritative medical treatise that the "cause of gale is
absolutely unknown." But even at this time, as it curiously happened,
there were certain ignorant laymen who had attained to a bit of medical
knowledge that was withheld from the inner circles of the profession. As
the peasantry of England before Jenner had known of the curative value
of cow-pox over small-pox, so the peasant women of Poland had learned
that the annoying skin disease from which they suffered was caused by
an almost invisible insect, and, furthermore, had acquired the trick of
dislodging the pestiferous little creature with the point of a needle.
From them a youth of the country, F. Renucci by name, learned the open
secret. He conveyed it to Paris when he went there to study medicine,
and in 1834 demonstrated it to his master Alibert. This physician, at
first sceptical, soon was convinced, and gave out the discovery to the
medical world with an authority that led to early acceptance.

Now the importance of all this, in the present connection, is not at all
that it gave the clew to the method of cure of a single disease. What
makes the discovery epochal is the fact that it dropped a brand-new
idea into the medical ranks--an idea destined, in the long-run, to
prove itself a veritable bomb--the idea, namely, that a minute and quite
unsuspected animal parasite may be the cause of a well-known, widely
prevalent, and important human disease. Of course the full force of this
idea could only be appreciated in the light of later knowledge; but even
at the time of its coming it sufficed to give a great impetus to that
new medical knowledge, based on microscopical studies, which had but
recently been made accessible by the invent