e and potash convert it into di-iodthymol,
which has been introduced in surgery under the names _aristol_ and
_annidalin_, as a substitute for iodoform.

_Borneol, Borneo camphor_ or camphol, also known as Malayan, Barus or
Dryobalanops camphor, C10H17OH, occurs in fissures in the wood of
_Dryobalanops aromatica_, a majestic tree flourishing in the East
Indies. This product is dextro-rotatory; the laevo and inactive
modifications occur in the so-called baldrianic camphor. Borneol melts
at 203 deg. and boils at 212 deg.. It is very similar to common or Japan
camphor, but has a somewhat peppery odour. Sodium and alcohol reduce
common camphor to a mixture of d- and l-borneol.

_Common camphor, Japan or Laurel camphor_, C10H16O, which constitutes
the bulk of the camphor of commerce, is the product of the camphor
laurel, _Cinnamonum camphora_, a tree flourishing in Japan, Formosa and
central China. It also occurs in various volatile oils, e.g. lavender,
rosemary, sage and spike. To extract the camphor, chips of the tree are
steamed, and the mixed vapours of camphor, volatile oils and water are
conducted to a condensing plant, where most of the camphor separates
out. This is filtered, and the remainder, about 20% of the total, which
is retained in solution, is extracted by fractional distillation and
cooling the distillate. The crude camphor so obtained is exported from
Japan in two grades--Samuel A and Samuel B. It is purified by mixing
with a little charcoal, sand, iron filings or quicklime and subliming,
by steam distillation or by crystallization. Common camphor forms a
translucent mass of hexagonal prisms, melting at 175 deg. and boiling at
204 deg. It sublimes very readily. In alcoholic solution it is
dextro-rotatory; the laevo form, Matricaria camphor, occurs in the oil
of _Matricaria parthenium_ and closely resembles the d form. Camphor
is chiefly used in the celluloid industry. The so-called "artificial
camphor" is pinene hydrochloride (see TERPENES).

Externally applied it acts medicinally as a counter-irritant, and, in
some degree, as a local anaesthetic, being also a definite antiseptic.
It is, therefore, largely used in liniments for the relief of myalgia,
sciatica, lumbago, etc. Combined with chloroform, thymol or carbolic
acid, it is a valuable local application for neuralgia and for toothache
due to dental caries. Taken internally, camphor is a nerve stimulant, a
diaphoretic and a feeble antipyretic. It is e