being formed. The
chemical basis of black Mustard is "sinnigrin" and its acid myronic.
The acridity of its oil is modified in the seeds by combination with
another fixed oil of a bland nature which can be readily separated by
pressure, then the cake left after the expression of this fixed oil is
far more pungent than the seeds. The bland oil expressed from the hulls
of the black seeds after the flour has been sifted away, promotes the
growth of the hair, and may be used with benefit externally for
[377] rheumatism. Whitehead's noted Essence of Mustard is made
with spirits of turpentine and rosemary, with which camphor and the
farina of black Mustard seed are mixed. This oil is very little
affected by frost or the atmosphere; and it is therefore specially
prized by clock makers, and for instruments of precision.

A Mustard poultice from the farina of black Mustard made into a
paste with, or without wheaten flour commingled, constitutes one of
the most powerful external stimulating applications we can employ.
It quickly induces a sharp burning pain, and it excites a destructive
outward inflammation which enters much more into the true skin
than that which is caused by an old fashioned blister of Spanish fly.
This has therefore superseded the latter as more promptly and
reliably effective for the speedy relief of all active internal
congestions. If the application of Mustard has caused sores, these
may be best soothed and healed by lime-water liniment.

Mustard flour is an infallible antiseptic and sterilising agent. It is
a capital deodoriser; and if rubbed thoroughly into the bands and nails
will take away all offensive stink when corrupt or dead tissues have
been manipulated.

If a tablespoonful of Mustard flour is added to a pint of tepid water,
and taken at a draught it operates briskly as a stimulating and sure
emetic. Hot water poured on bruised seeds of black Mustard makes
a good stimulating footbath for helping to throw off a cold, or to
dispel a headache; and meantime the volatile oil given out as an
aroma, if not too strong, proves soporific. This oil contains erucic,
and sinapoleic acids. When properly mixed with spirit of wine,
twenty-four drops of the oil to an ounce of spirit, the essential oil
forms, [378] by reason of its stimulating properties and its contained
sulphur, a capital liniment for use in rheumatism, or for determining
blood to the surface from deeper parts. Caution should be used not
to a