The drug aconite is the dried tuber of the monkshood (Fig. 178). This species and nearly related ones are among the most poisonous of plants. The juice of an East Indian species is used by the natives as an arrow-poison which is so powerful as to kill a tiger within a few minutes after it has been even slightly wounded with one of the poisoned arrows.

The chief active principle is aconitine (C33H45NO12) which is one of several poisonous alkaloids contained in the plant. Medicinally, aconite is used as an external application to relieve pain; but from what has been said it is plain that great caution should be observed to prevent the introduction of a poisonous quantity into the blood through a scratch or other slight wound in the skin.

Fig. 178. Monkshood (Aconitum Napellus, Crowfoot Family, Ranunculacece). Plant in flower. Flower. Same, with calyx removed. Flower, cut vertically. Fruit. Flower with sepals detached. Floral diagram. (Baillon.) Perennial herb about 1 m. tall, very poisonous; leaves dull green; flowers blue; fruit dry. Native home, Europe.

Fig. 178.-Monkshood (Aconitum Napellus, Crowfoot Family, Ranunculacece). Plant in flower. Flower. Same, with calyx removed. Flower, cut vertically. Fruit. Flower with sepals detached. Floral diagram. (Baillon.)-Perennial herb about 1 m. tall, very poisonous; leaves dull green; flowers blue; fruit dry. Native home, Europe.