An extract of the leaves and young shoots of Uncaria Gambir. Prepared at Singapore and in other places in the Eastern Archipelago.

Characters. - In cubes, about an inch in diameter, externally brown, internally ochrey-yellow or pale brick-red, breaking easily with a dull earthy fracture. Taste bitter, very astringent, and mucilaginous, succeeded by slight sweetness. Entirely soluble in boiling water. The decoction when cool is not rendered blue by iodine.

Composition. - Catechu chiefly contains a crystalline bitter substance, catechin or catechuic acid, C13H12O5, probably itself inactive; and catcchu-tannic acid, the active principle, isomeric with it, and into which it is rapidly converted by boiling or by the action of saliva, with the development of a red colour. Both catechuic and catechu-tannic acids give a green precipitate with persalts of iron.

Incompatibles. - The alkalies, metallic salts, and gelatine.

Dose. - 10 to 30 gr.

Preparations.

1. Infusum Catechu

Infusum Catechu. 1 in 27. Dose, 1 to 2 fl.oz.

2. Pulvis Catechu Compositus

Pulvis Catechu Compositus. Catechu, 4; Kino, 2; Rhatany,

2; Cinnamon, 1; Nutmeg, 1. Dose, 20 to 40 gr.

3. Tinctura Catechu

Tinctura Catechu. 1 in 8. Dose, 1/2 to 2 fl.dr.

4. Trochisci Catechu

Trochisci Catechu. 1 gr. in each. Dose, 1 to 6.

Action And Uses

Catechu acts like tannic acid, and is used for the same purposes. It is a favourite astringent application to sore throat in the form of the lozenge, and the compound powder and tincture are very commonly prescribed for diarrhoea.

Caffein. (Not Officinal) - An alkaloid obtained from Coffea arabica, the coffee plant; from Thea sinensis, the tea plant (nat. ord., Camelliaceae); from Ilex paraguayensis, Mate, or Paraguay Tea (nat. ord., Aquifoliacae); and from Guarana. (See page 211.)

Characters. - Caffein, C8H10N2O4, occurs in fine long silky white prisms, soluble in water, with a bitter taste. It is a feeble base. Tea contains 1 to 4 per cent. of caffein; coffee, 0.2 to 0.8: mate, 1.2; guarana, 5 per cent. It is closely aliied to theobromin, C7H8N4O2, being, in fact, methyl-theobromin, C7H9(CH3)N4O2, which can be made synthetically.

Incompatibles. - Tannic acid, iodide of potassium, and salts of mercury.

Dose. - 1 to 5 gr., or more.

Preparation. Citrate of Caffein, in white needles. Dose, 1 to 5 gr.

Action And Uses. 1. Immediate Local Action And Uses

Coffee stimulates most of the digestive glands, being siala-gogue, stomachic and slightly laxative. So far it is diete-tically wholesome.

2. Action In The Blood, And Specific Action And Uses

Caffein is absorbed into the circulation unchanged; and acts chiefly upon the central nervous system. The cerebrum is first stimulated, causing the clearness of intellect, the removal of languor, and the sleeplessness, familiar after a cup of strong coffee. Larger doses cause a species of narcotism; but there are great differences in this and other respects according to the individual and other circumstances. In the lower animals the spinal centres are simultaneously affected to such a degree that tetanic convulsions may occur, not unlike those caused by strychnia; but in man these effects on the lower centres are quite subsidiary. The sensory and motor peripheral nerves are not certainly affected. The muscle curve is altered in character, and muscular contraction seems more easily executed. The heart is first accelerated - another familiar effect of a full cup of coffee; it is then slowed and weakened. The blood pressure first rises and then falls. Respiration is temporarily increased, then depressed; and death occurs in this way. Metabolism is probably somewhat in creased, and the temperature raised. In all these respects habit markedly reduces the influence of coffee.

Coffee and caffein may be used as a nervine stimulant and restorative in ordinary conditions of fatigue. Megrim is fre-quently relieved by either. Large doses must be avoided.

3. Remote Local Action And Uses

Caffein is excreted unchanged in the bile and urine, the latter presenting the characteristic odour of the substance.

In passing through the kidney, it appears to stimulate the cells, at least in some subjects, and acts as a diuretic. Citrate of caffein is thus a powerful, hut somewhat uncertain, remedy in dropsy, whether cardiac or hepatic. It is best given after, and then along with, a stimulant diuretic, such as digitalis; for a short time; and in moderate doses.