Welsh is a substance found at a great depth in cavities of limestone
rocks. Ritson, in his "Fairy Tales," speaking of the fairies who
frequented many parts of Durham, relates how "a woman who had been in
their society challenged one of the guests whom she espied in the market
selling fairy-butter," an accusation, however, which was
deeply resented.

Browne, in his "Britannia's Pastorals," makes the table on which they
feast consist of:

"A little mushroom, that was now grown thinner
By being one time shaven for the dinner."

Fairies have always been jealous of their rights, and are said to resent
any infringement of their privileges, one of these being the property of
fruit out of season. Any apples, too, remaining after the crop has been
gathered in, they claim as their own; and hence, in the West of England,
to ensure their goodwill and friendship, a few stray ones are purposely
left on the trees. This may partially perhaps explain the ill-luck of
plucking flowers out of season[8]. A Netherlandish piece of folk-lore
informs us that certain wicked elves prepare poison in some plants.
Hence experienced shepherds are careful not to let their flocks feed
after sunset. One of these plants, they say, is nightwort, "which
belongs to the elves, and whoever touches it must die[9]." The disease
known in Poland as "elf-lock" is said to be the work of evil fairies or
demons, and is cured by burying thistle-seed in the ground. Similarly,
in Iceland, says Mr. Conway, "the farmer guards the grass around his
field lest the elves abiding in them invade his crops." Likewise the
globe-flower has been designated the troll-flower, from the malignant
trolls or elves, on account of its poisonous qualities. On the other