CONVOLVULUS SCAMMONIA.,. 
ance of the concrete alone is the proper test. The fracture 
is irregular, but smooth, faintly shining, and the sharp edges 
of the shivers are of a lighter gray color and translucent. It 
is pulverulent, and the powder has a light-gray color. Its 
specific gravity is 1.235 (Brisson). When it is of a dark 
color, heavy, and splintery, it should be rejected. When tritu- 
rated with water, nearly one fourth of it is dissolved, and the 
solution appears slightly mucilaginous, opaque, and of a 
greenish-gray color. ‘This solution is not affected by alcohol, 
solutions of superacetate and acetate of lead and sulphate of 
iron, nor precipitated by the acids; but with sulphuric acid it 
gives out the odor of vinegar. Solution of ammonia does 
not alter it, but that of potassa occasions a yellowish precipi- 
tate, which is quickly redissolved on the addition of an acid. 
Ether takes up two parts in ten of Scammony, and when 
evaporated leaves a brownish semitransparent resin. Alco- 
hol dissolves two thirds of its weight, but proof spirit is its 
best menstruum, taking up the whole except the impurities. 
Aleppo Scammony contains, according to Bouillon, La Grange, 
and Vogel, 0.60 of resin, 0.20 of extractive, 0.03 of gum, and 
0.35 of impurities. Smyrna Scammony contains 0.29 of resin, 
0.08 of gum, 0.05 of extractive, and 0.58 of impurities. 
When these impurities consist of flour, sand, or ashes, they 
may be detected by dissolving the sample in proof spirit, as 
they sink and remain undissolved; but Scammony is some- 
times also adulterated with the expressed juice of Cynanchum 
monspeliacum, and a fictitious Scammony is sold for the real, 
consisting of jalap, senna, manna, gamboge, and ivory black. 
mmony is a drastic cathartic, operating in general 
quickly and powerfully. The purest is that which is most 
active and soluble. The ancients were acquainted with its 
purgative qualities, and also employed it as an external ap- 
plication for removing hard tumors, itch, scurf, and fixed pains, 
but for the latter purposes it is now seldom or never used. It 
is a good purgative in the torpid state of the intestines, in 
_leucophlegmatic, hypochondriacal, and maniacal subjects; in 
- worm cases and the slimy state of the bowels to which chil- 
_ dren are subject; and as a hydragogue cathartic in dropsy. 
Scammony has been regarded by some as a cathartic of so 
irritating a nature as to require to be corrected by exposing it 
_to the fumes of sulphur, defecating it with lemon-juice and 
“other acids, and uniting it with demulcent mucilages ; but 
_ except in an inflamed or very irritable state of the bowels, it 
is a safe and efficacious purgative. It is, however, apt to 
_ gripe, on which account it is generally united with an aro- 
a ‘he dose is from five to fifteen grains, whether given in 
eras a bolus, or in the form of mixture triturated with 
