hunter knew every cranny of the greater part
of his environment with the accuracy born of long familiarity, but there
were some peaks which he could not scale, some caves which he could not
penetrate, some jungles into which he could not enter, and in these he
knew not what monsters might lurk or unknown beings might live. In
Celtic folk-lore the belief in fabulous monsters has not yet ceased. Man
was surrounded by dangers visible and invisible, and the time came when
some prehistoric man of genius propounded the view that all the objects
around him were no less living than himself. This animistic view of the
world, once adopted, made great headway from the various centres where it
originated, and man derived from it a new sense of kinship with his
world, but also new terrors from it. Knowing from the experience of
dreams that he himself seemed able to wander away from himself, he
thought in course of time that other living things were somehow double,
and the world around him came to be occupied, not merely with things that
were alive, but with other selves of these things, that could remain in
them or leave them at will. Here, again, this new prehistoric philosophy
gave an added interest to life, but it was none the less a source of
fresh terrors. The world swarmed with invisible spirits, some friendly,
some hostile, and, in view of these beings, life had to be regulated by
strict rules of actions and prohibitions. Even in the neolithic stage
the inhabitants of Celtic countries had attained to the religious ideas
in question, as is seen not only by their folk-lore and by the names of
groups of goddesses such as the Matres (or mothers), but by the fact that
in historic times they had advanced well beyond this stage to that of
named and individualised gods. As in all countries where the gods were
individualised, the men of Celtic lands, whether aborigines or invaders,
had toiled along the steep ascent from the primitive vague sense of being
haunted to a belief in gods who, like Esus, Teutates, Grannos, Bormanus,
Litavis, had names of a definite character.

Among the prohibitions which had established themselves among the races
of Celtic lands, as elsewhere, was that directed against the shedding of
the blood of one's own kin. There are indications, too, that some at any
rate of the tribes inhabiting these countries reckoned kinship through
the mother, as in fact continued to be the case among the Picts of
Scotlan