This section is from the book "A Text Book Of Materia Medica, Being An Account Of The More Important Crude Drugs Of Vegetable And Animal Origin", by Henry G. Greenish. Also available from Amazon: A Text Book of Materia Medica : Being an Account of the More Important Crude Drugs of Vegetable and Animal Origin.
The scammony plant is a twining plant indigenous to the eastern Mediterranean and resembles the common bindweed, but is much larger. It produces a root attaining as much as a metre in length and 10 cm. in thickness, from which a number of slender aerial stems spring. The gum-resin is collected in Asiatic Turkey, chiefly near Smyrna and Aleppo.
The abnormal structure of the root has been already alluded to (see Scammony Root). In the cortex as well as in the parenchyma surrounding each of the columns of wood are cells containing a resinous emulsion. These cells are arranged in vertical rows, and when an incision is made the contents drain from a series of cells by the breaking of the transverse walls. In collecting the drug the workman clears away the earth surrounding the upper part of the root so as to leave 10 or 15 cm. of the root exposed. This is then cut off in a slanting direction 5 to 10 cm. below the crown, and a mussel shell is stuck into it just beneath its lowest edge so as to receive the milky sap which instantly flows out. The shells are usually left till the evening, when they are collected and the cut parts of the roots scraped with a knife so as to remove any partially dried drops of juice ('Pharmacographia'). If the gum-resin were then dried at once a drug of fine golden brown colour and translucent appearance would be produced; but as a rule the contents of the shells are collected, and daily added to, until a sufficient quantity has accumulated; this is then softened, mixed into a homogeneous mass, and allowed to dry. During the long standing in a more or less moist condition the scammony undergoes a fermentative change, and the drug when dry has a dark colour and porous appearance when broken. It is also frequently adulterated whilst in the soft state.
Scammony is usually imported in flattened cakes about 1.5 cm. thick and 10 or 15 cm. in diameter. It varies in colour from dark grey to dark brown or nearly black, the surface being often covered with a grey powder. It breaks very readily, and the freshly exposed surface is glossy, resinous, often more or less porous, and of a dark brown or nearly black colour. Thin fragments, however, when viewed by transmitted light, are seen to be brown in colour and translucent. It is very easily reduced to an ash-grey powder, and readily yields a milky emulsion when rubbed with water. Scammony has a characteristic cheesy odour and an acrid taste.
Very fine qualities of the drug which, however, are scarce, differ in being of a golden brown colour, almost transparent in thin fragments, and less porous.
The student should observe its brittle nature, translucent brown colour in thin fragments, and characteristic odour; it yields a milky emulsion when rubbed with the wet finger, a character that distinguishes it from scammony resin, which does not emulsify when so treated.
Pure scammony contains about 88 or 90 per cent of resin identical with that obtained from the root (see p. 351) and entirely soluble in ether; the residue consists principally of gum. But scammony of such purity as this is seldom met with in commerce. Good qualities yield from 70 to 80 per cent, of resin to ether, and are known as ' virgin ' scammony.
Scammony is used as a brisk cathartic and vermifuge, especially for children.
The high price of scammony and its plastic nature before it is dried invite and facilitate adulteration. Starch, chalk, and earthy matter are frequently used to increase its weight, and occasionally other resins are fraudulently mixed with it.
Adulteration with inorganic matter is readily detected by incineration. Good scammony should not yield more than 3 per cent, of ash. Starch is easily recognised by microscopical examination or by the iodine test, but traces of the starch of scammony root are often present in genuine scammony, and caution must be used in concluding that the drug has been adulterated. Most foreign resins may be detected by dissolving the drug in hot solution of potassium hydroxide; on the addition of an acid, scammony resin is not precipitated whereas most foreign resins are.
Inferior scammony is usually tough and has a dull fracture, small splinters being opaque instead of translucent. Factitious scammony that was practically free from resin soluble in ether has even been offered for sale as genuine scammony.