The bark of Quillaia Saponaria. Chili.

Characters. - Flat, large pieces, about one-fifth of an inch (5 millimetres) thick; outer surface brownish-white, often with small patches of brown cork attached, otherwise smooth; inner surface whitish, smooth; fracture splintery, checkered with pale brownish bast-fibres embedded with white tissue; inodorous, very acrid and sternutatory.

Composition. - It contains a glucoside, saponin. Saponin is also contained in senega and sarsaparilla. It appears to be identical with cyclamin from Cyclamen europceum and with pri-mulin from Primula officinalis. Digitonin from digitalis appears to be a kind of saponin differing somewhat from the others.

Action and Uses. - The bark has little or no application in medicine. The powder when snuffed provokes sneezing. Its infusion and extract are used for cleaning cloth and taking out stains. On account of the saponin it contains, the infusion froths easily and the froth remains long. A little of it is sometimes added to syrups, lemonade, or other drinks, to give them a head. It also retains fine powders in suspension and forms emulsions. It is used to form an emulsion with coal-tar.

Saponin when applied locally acts as a powerful irritant, local anaesthetic, and muscular poison. On account of its local irritant action, it produces most intense pain when injected sub-cutaneously; sneezing when applied to the nose; vomiting, diarrhoea, and gastro-enteritis when taken internally in large doses. Locally applied it paralyses nerves both sensory and motor, and muscular fibre both voluntary and involuntary. It therefore produces local paralysis and local anaesthesia when injected under the skin in a frog's leg. The muscles and motor nerves being paralysed, no irritation to either will cause contraction; and the sensory nerves being also paralysed, local irritation does not produce reflex action. In the voluntary muscles it produces a condition of rigor mortis, and the muscular substance becomes brittle and structureless, as after myositis.

When locally applied to the intestine, either by internal administration or injection into the peritoneal cavity, it paralyses the involuntary muscular fibre of the intestinal wall.

Preparation.

Dose.

Aqua Laurocerasi (prepared by mixing the leaves, 1 lb., with water 2 1/2 pints, distilling off one pint, and bringing the distillate to the strength of 0.1 per cent. of real hydrocyanic acid by diluting with water, or by adding hydrocyanic acid as required).................................................

1/2-2 fl. dr.

When applied to the heart it causes rapid stoppage in diastole. It counteracts the effect of digitalis on the heart, and vice versa digitalis counteracts the effect of saponin on the heart, so that when the ventricle of the frog's heart has been brought to a standstill by one of these drugs, its pulsations may be restored by the other.

When absorbed into the circulation, saponin paralyses the nerve-centres in addition to the nerves and muscular structures. The symptoms it produces depend on the mode in which it is introduced into the body and the structures which it first reaches in consequence. If injected into the jugular vein so as to reach the heart first, it usually kills by producing cardiac paralysis, with slow pulse, and rapid fall of blood-pressure, and convulsions which are probably asphyxial and due to the failure of circulation (p. 239), respiratory movements still continuing. Saponin also paralyses the respiratory and vaso-motor centres, so that the blood-pressure falls much and the respirations become feeble and slow. In large doses saponin may paralyse the respiratory centre before the heart, so that death ensues from failure of the respiration while the heart continues to beat.

It is possible that quillaia might be used instead of sarsa-parilla, and it might perhaps be useful in cases of aortic disease with hypertrophy (p. 338).