interpreted as a symptom of demonic possession. Primitive man had no
reason to know that the phenomenon of menstruation was in any way
connected with reproduction. The typical explanation was probably very
much like that of the Zoroastrians, who believed that the menses were
caused by the evil god Ahriman. A woman during the period was unclean
and possessed by that demon. She must be kept confined and apart from
the faithful, whom her touch would defile, and from the fire, which her
very look would injure. To this day there is in the house of the Parsee
a room for the monthly seclusion of the women, bare of all comforts, and
from it neither sun, moon, stars, fire, water, nor any human being can
be seen.[11]

All the ancient civilizations had such taboos upon the menstruous woman.
According to Pliny, the Romans held that nothing had such marvellous
efficacy as, or more deadly qualities than, the menstrual flow. The
Arabs thought that a great variety of natural powers attached
themselves to a woman during the menstrual period.[12, p.448] Rabbinic
laws demand that "a woman during all the days of her separation shall be
as if under a ban." The epithet Niddah, applied to a woman at that time,
means "to lay under a ban." The reconstruction of the ancient Assyrian
texts shows that the law of the unclean taboo on the woman in her
courses holds for them. Up to the present time the Semitic woman is
carefully segregated from the rest of the tribe, often for a long time,
and becomes taboo again on each successive occasion.[13] Peoples in the
eastern Mediterranean region will not permit a woman in her courses to
salt or pickle; whatever she might prepare would not keep. This belief
survives among the folk to-day in America, and was evidently brought
early in the history of the country, for it is common among pioneer
stock.