il the year
1665.

The appointment of a forty days' detention, whence quarantines derive
their name, was not dictated by caprice, but probably had a medical
origin, which is derivable in part from the doctrine of critical days;
for the fortieth day, according to the most ancient notions, has been
always regarded as the last of ardent diseases, and the limit of
separation between these and those which are chronic. It was the custom
to subject lying-in women for forty days to a more exact superintendence.
There was a good deal also said in medical works of forty-day epochs in
the formation of the foetus, not to mention that the alchemists expected
more durable revolutions in forty days, which period they called the
philosophical month.

This period being generally held to prevail in natural processes, it
appeared reasonable to assume, and legally to establish it, as that
required for the development of latent principles of contagion, since
public regulations cannot dispense with decisions of this kind, even
though they should not be wholly justified by the nature of the case.
Great stress has likewise been laid on theological and legal grounds,
which were certainly of greater weight in the fifteenth century than in
the modern times.

On this matter, however, we cannot decide, since our only object here is
to point out the origin of a political means of protection against a
disease which has been the greatest impediment to civilisation within the
memory of man; a means that, like Jenner's vaccine, after the small-pox
had ravaged Europe for twelve hundred years, has diminished the check
which mortality puts on the progress of civilisation, and thus given to
the life and manners of the nations of this part of the world a new
direction, the result of which we cannot foretell.

THE DANCING MANIA

CHAPTER I--THE DANCING MANIA IN GERMANY AND THE NETHERLANDS

SECT. 1--ST. JOHN'S DANCE

The effects of the Black Death had not yet subsided, and the graves of
millions of its victims were scarcely closed, when a strange delusion
arose in Germany, which took possession of the minds of men, and, in
spite of the divinity of our nature, hurried away body and soul into the
magic circle of hellish superstition. It was a convulsion which in the
most extraordinary manner infuriated the human frame, and excited the
astonishment of contemporaries for more than two centuries, since which
time it has never reappeared. It w