This section is from the book "Ancient Legends, Mystic Charms, And Superstitions Of Ireland", by Jane Francesca Wilde. Also available from Amazon: Ancient Legends, Mystic Charms, And Superstitions Of Ireland.
When a person becomes low and depressed and careless about everything, as if all vital strength and energy had gone, he is said to have got a fairy blast. And blast-water must be poured over him by the hands of a fairy doctor while saying, " In the name of the saint with the sword, who has strength before God and stands at His right hand." Great care being taken that no portion of the water is profaned. Whatever is left after the operation, must be poured on the fire.