f wine; and the dose of this in a diluted form is from
five to ten drops, of the third decimal strength, two or three times a
day, with a spoonful of water. The condition which indicates its
medicinal use, is that of a severe catarrh, with chilliness, a heavy
head, sneezing, a dry mouth, and general aching, lassitude, with
stupor, and heat of face. Its chemical constituents have not been
ascertained. In the Isle of Skye it is used for causing salivation, as
a vegetable mercury; and _per contra_ for curing a sore mouth.

Such virtues as the herb possesses were thought to have been taught
by the god Mercury. The Greeks called it Mercury's Grass (_Ermou
poa_). When boiled and eaten with fried bacon in error for the
English spinach, Good King Henry, it has produced sickness,
drowsiness, and convulsive twitchings. The root affords both a blue
and a crimson colour for dyeing.

MINTS. (Pennyroyal, Peppermint, and Spearmint).

Several kinds of the Mints have been used medicinally from the
earliest times, such as Balm, Basil, Ground Ivy, Horehound,
Marjoram, Pennyroyal, Peppermint, Rosemary, Sage, Savory,
Spearmint, and Thyme, some being esteemed rather as pot herbs,
than as exercising positive medicinal effects. The most useful as
Herbal Simples which have yet to be considered are Pennyroyal,
Peppermint, and Spearmint. The Cat Mint (_Nepeta cataria_) and
Horse Mint are of minor importance.

[334] All the Mints are severally provided with leaves of a familiar
fragrant character, it having been observed that this aromatic
vegetation is a feature of deserts, and of other hot, dry places,
allover the world. Tyndall showed the power exercised by a spray of
perfume when diffused through a room to cool it, or in other words
to exclude the passage of the heat rays; and it has been suggested
that the presence of essential oils in the leaves of these plants
serves to protect them against the intense dry heat of a desert sun
all effectively as if they were partly under shelter. Nevertheless
Mints, with the exception of "Arvensis," are the inhabitants of wet
and marshy wastes.

They have acquired their common name _Mentha_ from Minthes
(according to Ovid) who was changed into a plant of this sort by
Proserpina, the wife of Pluto, in a fit of jealousy. Their flowering
tops are all found to contain a certain portion of camphor. Pliny
said: "As for the garden Mint, the very smell of it alone recovers
and refreshes the spirits, as t