In the northern sagas, and in the old ballads and saintly legends of the Middle Ages—­supernatural agents who played a prominent part—­there are giants of enormous size and little dwarfs who can make themselves invisible, and do all sorts of good to their favourites, and harm to their enemies.  We are also introduced there to dragons and other monsters which have human understandings, and, guided by a wicked spirit, could do great mischief.  Such beings took the place of the ancient divinities, and in many cases when the hero or saint is in great straits, in combat with these evil spirits or fiends, Jesus Christ comes to their assistance.  One instance will exemplify this: 

   “O’er him stood the foul fiends,
    And with their clubs of steel,
    Struck him o’er the helmit
    That in deadly swound he fell. 
    But God his sorrow saw,
    To the fiends his Son he sent;
    From the earth they vanished
    With howling and lament. 
    The Christian hero thanked his God,
    From the ground he rose with speed,
    Joyfully he sheathed his sword,
    And mounted on his steed.”

    Illustrations of “Northern Antiquities."

By the beginning of this century these ideas of the personel of supernatural agencies had become slightly modified in this country at least, giants and dragons having given way to fairies, brownies, elves, witches, etc.  The Rev. Mr. Kirk, of Aberfeldy, published a work descriptive of these supernatural beings.  He says they are a kind of astral spirits between angels and humanity, being like men and women in appearance, and similar in many of their habits; some of them, however, are double.  They marry and have children, for which they keep nurses; have deaths and burials amongst them, and they can make themselves visible or invisible at pleasure.  They live in subterranean habitations, and in an invisible condition attend very constantly on men.  They are very fond of human children and pretty women, both of which they will steal if not protected by some superior influence.  Women in childbed stand in danger of being taken, but if a piece of cold iron be kept in the bed in which they lie, the spirits won’t come near.  Children are in greater danger of being stolen before baptism than after.  They sometimes, to supply their own needs, spirit away the milk from cows, but more frequently they transfer the milk to the cows of some person who stands high in their favour.  This they do by making themselves invisible, and silently milking and removing the milk in invisible vessels.  When people offend them they shoot flint-tipped arrows, and by this means kill either the persons who have offended them or their cattle.  They cause these arrows to strike the most vital part, but the stroke does not visibly break the skin, only a blae mark is the result visible on the body after death.  These flint arrow-heads are occasionally found, and the possession of one