gards the restriction not so much as a
matter of good omen, _i.e._ of freedom from contamination by the death
of a parent, but as pointing to a notion that they were "fuller of life
and therefore luckier than orphans."[366] Whether or no this explanation
is the right one, it is quite consistent, as we shall see directly, with
the general idea of sacrifice at Rome, and the learning by which it is
supported is in any case of interest and value.

There is abundant evidence from historical times that all worshippers,
and therefore _a fortiori_ all priests, when sacrificing, had to be
personally clean and free from every kind of taint; a rule which also
held good for the utensils used in the worship, which in many cases at
least were of primitive make and material, not such as were in common
use.[367] The need of personal purity is well expressed by Tibullus in
his description of a rural festival[368]:--

vos quoque abesse procul iubeo, discedat ab aris
cui tulit hesterna gaudia nocte Venus.
casta placent superis: pura cum veste venite
et manibus puris sumite fontis aquam.

These lines indicate an approach at least to the idea of mental as well
as material purity; and Cicero in his _ius divinum_ in the _de
Legibus_[369] actually reaches that idea: "caste iubet lex adire ad
deos, animo videlicet, in quo sunt omnia: nec tollit castimoniam
corporis," etc. But this is the language of a later age, and does not
reflect the notions of the old Roman, but rather those of the religious
philosophy of the Greek. The personal purity which the Roman rule
required was a survival from a set of primitive ideas, closely connected
with taboo, which we are only now beginning to understand fully. They
are common to all or almost all peoples who have made any progress in
systematising their sacrificial worship. As Dr. Westermarck has
recently expressed it,[370] "they spring from the idea that the contact
of a polluting substance with anything holy is followed by injurious
consequences. It is supposed to deprive a deity or holy being of its
holiness.... So also a sacred act is believed to lose its sacredness by
being performed by an unclean individual." And in the next sentence he
goes still farther back in the history of the belief, pointing out that
a polluting substance is itself held to contain mysterious energy of a
baneful kind. But I must leave this interesting subject now; the story
of the evolution of the habit of cleanline