It forms tasteless yellowish prisms, sparingly soluble in alcohol, requiring about 5000 parts of water for solution. With alkalis it yields intensely yellow crystallizable compounds, which, however, are easily decomposed already by carbonic acid. Gentianin may be sublimed if carefully heated at 250° C. By melting it with caustic potash, acetic acid, phloroglucin, C₆H₃(OH)₃, and oxysalicylic acid, C₆H₃(OH)₂COOH, are produced, as shown in 1875 by Hlasiwetz and Habermann. The name of gentianic acid or gentisinic acid had been applied to the oxysalicylic acid obtained by the above decomposition before it was identified with oxysalicylic acid from other sources.
Gentian root abounds in pectin; it also contains, to the extent of 12 to 15 per cent., an uncrystallizable sugar, of which advantage is taken in Southern Bavaria and Switzerland for the manufacture by fermentation and distillation of a potable spirit.[1616] This use of gentian and its consumption in medicine have led to the plant being almost extirpated in some parts of Switzerland where it formerly abounded.
The experiments of Maisch (1876) and Ville (1877) have shown tannic matters to be absent from the root.
Commerce—Gentian root finds its way into English commerce through the German houses; and some is shipped from Marseilles. The quantity imported into the United Kingdom in 1870 was 1100 cwt.
Uses—Gentian is much used in medicine as a bitter tonic. Ground to powder, the root is an ingredient in some of the compositions sold for feeding cattle.
Substitutes—It can hardly be said that gentian is adulterated, yet the roots of several other species possessing similar properties are occasionally collected; of these we may name the following:—
1. Gentiana purpurea L.—This species is found in Alpine meadows of the Apennines, Savoy and Switzerland, in Transylvania, and in South-western Norway; a variety also in Kamtchatka.[1617] The root is frequently collected;[1618] it attains at most 18 inches in length and a diameter of about 1 inch at the summit, from which arise 8 to 10 aerial stems, clothed below with many scaly remains of leaves. The top of the root has thus a peculiar branched appearance, never found in the root of G. lutea, with which in all other respects that of G. purpurea agrees. The latter is perhaps even more intensely bitter.
2. G. punctata L.—Nearly the same description applies to this species, which is a native of the Alps of South-Eastern France, Savoy, the southern parts of Switzerland, extending eastward to Austria, Hungary and Roumelia.
3. G. pannonica Scop.—a plant of the mountains of Austria, unknown in the Swiss Alps, has a root which does not attain the length or the thickness of the root of G. purpurea, with which it agrees in other respects. It is officinal in the Austrian Pharmacopœia.
4. G. Catesbœi Walter (G. Saponaria L.)—indigenous in the United States. Its root, usually not exceeding 3 inches in length by ⅓ inch in diameter, has a very thin woody column within a spongy whitish cortical tissue and a bright yellow epidermis. This root is less bitter than the above enumerated drugs; the same remark applies also to those European Gentianæ which like G. Catesbœi are provided with blue flowers.