them. The incantation itself, _fith-fath_, is still remembered in
Highland glens.[1109] In the case of S. Patrick he and his followers
appeared as deer, and this power of shape-shifting was wielded both by
Druids and women. The Druid Fer Fidail carried off a maiden by taking
the form of a woman, and another Druid deceived Cuchulainn by taking the
form of the fair Niamh.[1110] Other Druids are said to have been able to
take any shape that pleased them.[1111] These powers were reflected back
upon the gods and mythical personages like Taliesin or Amairgen, who
appear in many forms. The priestesses of Sena could assume the form of
animals, and an Irish Circe in the _Rennes Dindsenchas_ called Dalb the
Rough changed three men and their wives into swine by her spells.[1112]
This power of transforming others is often described in the sagas. The
children of Lir were changed to swans by their cruel stepmother; Saar,
the mother of Oisin, became a fawn through the power of the Druid Fear
Doirche when she rejected his love; and similarly Tuirrenn, mother of
Oisin's hounds, was transformed into a stag-hound by the fairy mistress
of her husband Iollann.[1113] In other instances in the sagas, women
appear as birds.[1114] These transformation tales may be connected with
totemism, for when this institution is decaying the current belief in
shape-shifting is often made use of to explain descent from animals or
the tabu against eating certain animals. In some of these Irish
shape-shifting tales we find this tabu referred to. Thus, when the
children of Lir were turned into swans, it was proclaimed that no one
should kill a swan. The reason of an existing tabu seemed to be
sufficiently explained when it was told that certain human beings had
become swans. It is not impossible that the Druids made use of hypnotic
suggestion to persuade others that they had assumed another form, as Red
Indian shamans have been known to do, or even hallucinated others into
the belief that their own form had been changed.

By a "drink of oblivion" Druids and other persons could make one forget
even the most dearly beloved. Thus Cuchulainn was made to forget Fand,
and his wife Emer to forget her jealousy.[1115] This is a reminiscence
of potent drinks brewed from herbs which caused hallucinations, e.g.
that of the change of shape. In other cases they were of a narcotic
nature and caused a deep sleep, an instance being the draught given by
Grainne to Fionn and hi