ly some primeval terror
or aversion evoked by certain objects, as we see animals shrink with
disgust at the sight or smell of blood. The nerves of savage man are
strangely excited by certain stimuli of touch, smell, taste, sight; the
specially exciting object is something that we should call mysterious,
weird, or uncanny."

Based on this notion of constant danger from infection, there arose a
code of unwritten custom as rigid as that enforced by a careful
physician in infectious cases at the present day; and thus, too, in
course of time there was developed the idea of the possibility of
_disinfection_, an idea as salutary as the discovery in medical science
of effective methods for the disinfection of disease. The code of taboo
had an obvious ethical value, as Dr. Jevons pointed out long ago;[28]
like all discipline carried out with a social end in view, it helped men
to realise that they were under obligations to the community of which
they were a part, and that they would be visited by severe penalties if
they neglected these duties. But it inevitably tended to forge a set of
fetters binding and cramping the minds of its captives with a countless
number of terrors; life was full of constant anxiety, of that feeling
expressed by the later Romans in the word _religio_,[29] which, as we
shall see, probably had its origin in this period of primitive
superstition. The only remedy is the _discovery of the means of
disinfection_, or, as we commonly call it, of _purification_: a
discovery which must have been going on for ages, and only finds its
completion at Rome in the era of the City-state. We shall return to this
part of the subject when we deal with the ritual of purification; at
present we must attend to certain survivals in that ritual which suggest
that at one time the ancestors of the Roman people lived under this
unwritten code of taboo.

Let us see, in the first place, how human beings were supposed to be
affected by this mysterious influence under certain circumstances and at
particular periods of their existence. As universally in primitive life,
the new-born infant must originally have been taboo; for every Roman
child needed purification or disinfection, boys on the ninth, girls on
the eighth day after birth. This day was called the _dies lustricus_,
the day of a purificatory rite; "est lustricus dies," says Macrobius,
"_quo infantes lustrantur_ et nomen accipiunt."[30] In historical times
the naming of the