Cannabis consists of the dried flowering and fruiting tops of the pistillate
plant of Cannabis sativa Linn. (Fam. Cannabinaceæ), an annual
dioecious herb indigenous to Central Asia and the Northern and Western
Himalayas, and cultivated mainly in tropical districts of India, Africa, and
North America.
Cannabis occurs in flattened, dull green masses which remain more or less
compacted together by the adhesive resinous secretion. The tops vary in
length from about 3 to 30 centimetres, the smaller tops being preferred;
they consist of the upper part of the stem with ascending branches, which
are longitudinally furrowed and bear numerous covering and glandular
trichomes. The leaves are alternate and consist of simple or palmately
compound bracts, each having two linear stipules and bearing in its axil two
bracteoles, each of which subtends a single pistillate flower or a more or
less developed fruit occasionally containing an oily seed. The taste is very
slight and the odour somewhat heavy and narcotic.
The diagnostic microscopical characters are the conical, curved,o
unicellular cystolith-trichomes with enlarged bases; the similar but more
slender trichomes without cystoliths; the numerous, usually 8-celled,
rosette-shaped, glandular trichomes with either unicellular or multiseriate
pedicels; the bracteoles with very numerous small cluster-crystals of
calcium oxalate; the red stigmas with long cylindrical papillæ
laticiferous tubes with brown contents; occasional, more or less lignified,
phloem fibres from the stem, and brown, thick-walled, pitted cells from the
palisade layer of the pericarp.
Cannabis contains a soft, brown resin (cannabinone), the chief
constituent of which is cannabinol,
C21H26O2, a
viscid, reddish oil, possessing a powerful narcotic action, but resinifying
and becoming less active on exposure to air; choline, and traces of volatile
oil, fat, and wax are also present. Cannabis yields to alcohol (90 per cent)
from 10 to 22 per cent of extractive. The ash is about 15 per cent. The
following test has been used for the identification of cannabis: Shake 0.1
gramme in powder with 5 millilitres of light petroleum for three minutes and
filter; to 1 millilitre of the filtrate add 2 millilitres of a 15 per cent
w/v solution of hydrogen chloride in dehydrated alcohol; at the junction of
the two liquids a red colouration appears, and, after shaking, the upper
layer becomes colourless and the lower layer acquires an orange-pink
colouration which disappears on the addition of one millilitre of water.
Varieties: Tinctures of cannabis, prepared from African, American,
German, and Indian varieties of the drug, when examined by oral
administration to cats appear to possess about the same degree of activity,
and this activity is not destroyed by long storage of the drug in a dry
condition.
Standard: Cannabis contains not more than 10 per cent of fruits,
large foliage leaves, and stems over 3 millimetres in diameter, and not more
than 2 per cent of other foreign organic matter. Acid-insoluble ash, not
more than 5 per cent. When a mixture of 10 grammes of finely powdered
cannabis and 100 millilitres of alcohol (90 per cent) is shaken occasionally
during twenty-four hours and then filtered, 20 millilitres of the filtrate,
evaporated in a flat-bottomed dish, yields a residue weighing, when dried at
100 degrees, not less than 0.20 gramme. Cannabis indicæ herba I.A.
consists of the tops, in flower and in fruit, of the female plant cultivated
in the East Indies.
Cannabis, in powder (Pulvis Cannabis : Pulv. Cannab.), contains the
constituents and possesses the diagnostic microscopical characters of
Cannabis, and complies with the limits for acid-insoluble ash and residue on
extraction with alcohol (90 per cent) of the unground drug.
Action and Uses: Cannabis acts chiefly on the central nervous system.
It first produces excitement with hallucinations, a feeling of happiness and
indifference to surroundings, this stage being followed by deep sleep. The
hallucinations include inability to estimate time and space. In the East the
hemp is smoked and almost immediately produces symptoms of pleasurable
excitement, followed by depression and lethargy. Cannabis is used as an
anodyne sedative or hypnotic in mania, spasmodic coughs, phthisis, asthma,
and dysmenorrhoea. It has been used in the treatment of chorea and paralysis
agitans. It does not produce constipation or loss of appetite. Cannabis is
usually administered as the extract in pills, or as tincture. In
cases of poisoning the stomach should be evacuated and the usual
methods adopted to prevent collapse and respiratory failure.
CANNABINÆ TANNAS: Cannabine tannate is a brownish powder which
may be obtained from an aqueous extract of cannabis by precipitation with
tannic acid. It has been used as a hypnotic in nervous insomnia, in
dysmenorrhoea and in menorrhagia. Dose - 0.25 to 0.5 gramme (4 to 8
grains).
CANNABINONUM: Cannabinone, the brown resin obtained from cannabis,
has been used as a hypnotic in hysteria and insomnia. Dose - 0.016 to 0.06
gramme (1/4 to 1 grain).
| Metric | Imperial | |
|---|---|---|
| Cannabis, in coarse powder | 1000 g | 16 oz. |
| Alcohol (90 per cent) | (sufficient) |
Exhaust the cannabis by percolation with the alcohol and evaporate to a soft extract.
Dose: 0.016 to 0.06 gramme (1/4 to 1 grain).
In making this preparation the alcohol (90 per cent) may be replaced by industrial methylated spirit diluted so as to be of equivalent alcoholic strength, provided that the law and the statutory regulations governing the use of undustrial methylated spirit are observed.
This extract replaces the Extractum Cannabis Indicæ of the British Pharmacopoeia, 1914, which was prepared in the same way from Indian cannabis (Cannabis Indica).
| Metric | Imperial | |
|---|---|---|
| Extract of Cannabis | 50 g | 1 oz |
| Alcohol (90 per cent) | to 1000 ml | to 20 fl oz |
Dissolve.
Dose: 0.3 to 1 millilitre (5 to 15 minims).
Alcohol content, 83 to 87 per cent v/v of ethyl alcohol.
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