QUALITIES. _Form_, blackish-grey cakes; _Taste_, bitter and sub-acrid;
_Odour_, heavy and peculiar; when rubbed with water, the surface lathers
or _lactifies_. _Specific gravity_ 1·235. CHEMICAL COMPOSITION. Resin is
the principal constituent; 16 parts of good _Aleppo_ Scammony yield 11
parts of resin, and 3½ of watery extract. That from _Smyrna_ contains
not more than half the quantity of resin, but more extractive, and gum.
SOLUBILITY. Water, by trituration, takes up one-fourth, alcohol
two-thirds, and proof spirit dissolves all, except the impurities.
INCOMPATIBLE SUBSTANCES. Neither acids, metallic salts, nor ammonia,
produce any change in its solutions, but the fixed alkalies occasion
yellow precipitates; and yet they do not appear to be _medicinally_
incompatible with it; thus Gaubius, “_Scammoneum acidi commixtio[631]
reddit inertius; alcali fixum, contra, adjuvat_.” The mineral acids
appear to destroy a part of the substance, without in the least altering
the rest. The discrepancy which exists in authors respecting the power
of this drug, seems to have arisen from its operation being liable to
uncertainty, in consequence of peculiar states of the alimentary canal;
for instance, where the intestines are lined with an excess of mucus, it
passes through without producing any action, but where the natural mucus
is deficient, a small dose of scammony may irritate and even inflame the
bowels. In this latter case, my practice has been to administer the
purgative in a mucilaginous draught, or emulsion. MED. USES. It is an
efficacious and powerful cathartic, very eligible in worm cases, and in
the disordered state of the bowels which so commonly occurs in children.
DOSE, grs. iij to xv, in the form of powders triturated with sulphate of
potass, sugar, or almonds; when given alone, it is apt to irritate the
fauces; it may be also administered as a solution, effected by
triturating it with a strong decoction of liquorice, and straining.
(_Form. 78, 83._) OFFICINAL PREPARATIONS. _Confect: Scammon:_ L.D.
_Pulv: Scammon: co._ L.E. _Extract: Colocynth: co._ L. (=F=) _Pulv.
Sennæ, co_. L.[632] (=F=) ADULTERATIONS. Two kinds of Scammony are
imported into this country, that from _Aleppo_, which is the best; and
that from _Smyrna_, which is more compact and ponderous, but less pure:
it is commonly mixed with the expressed juice of the _cynanchum
monspeliacum_; it is also sophisticated with _flour_, _sand_, and
_ashes_; their presence may be detected by dissolving the sample in
proof spirit, when the impurities will sink, and remain undissolved;
carbonate of lime is moreover frequently added to Scammony, in which
case the sample will effervesce in acids: there is however a compound
bearing the name of Scammony, to be met with in the market, which is
altogether factitious, consisting of jalap, senna, manna, gamboge, and
ivory black. Good Scammony ought to be friable, and when wetted with the
finger, it should _lactify_, or become milky: and the powder should
manifest its characteristic odour, which has been compared to that of
old ewe milk cheese.