_Physiological action._ The alkaloids generally possess great medicinal power; some of them act with terrific energy, and are the most violent poisons with which we are acquainted. Perfectly pure aconitia is about 200 times more poisonous than arsenic, and at least 50 times more poisonous than ordinary medicinal prussic acid. The greater number act on animals in the same way as the plants which produce them, provided they are given in proportionately small doses. Many of them, when judiciously administered, are most valuable medicines. _Pois., Ant., &c._ Some of the alkaloids act as narcotic or stupefying poisons; others are classed with the narcotico-acrid poisons, or those which produce both narcotism and irritation of the parts they touch. The general symptoms produced by opium and its preparations may be taken as an example of the former; those from aconite and strychnia, of the latter. In large doses of the greater number, narcotism predominates; in smaller ones, irritation; they are rarely coexistent.——_Treatm._ No common antidote to the effects of this class of substances has yet been discovered. The only safe treatment, of at all general application, is to immediately clear the stomach by means of a strong and quick-acting emetic (as sulphate of zinc), or the stomach-pump, and to administer copious and continued draughts of astringent vegetable solutions (as of tannin, nut-galls, oak-bark, or what is always at hand——very strong tea or coffee). These may be followed by or combined with a smart purge of castor oil, as soon as the stomach is thoroughly cleared of the poison. M. Bouchardat strongly recommends a solution of iodine, 3 gr., and iodide of potassium, 6 gr., in pure water, 16 fl. oz., in cases of poisoning by OPIUM, ACONITE, COLCHICUM, DEADLY NIGHTSHADE, HEMLOCK, NUX VOMICA, &c., or by the alkaloids obtained from them——ACONITINE, ATROPIA, COLCHICINA, CONIA, MORPHIA, STRYCHNIA, &c., or their salts; but _not_ where foxglove or digitalin has been taken. The stomach having been well emptied by an emetic, the solution is to be given by wine-glassfuls for some time; the vomiting being still encouraged during the early part of the administration of the antidote. In the case of narcotics (as opium, morphia, &c.), this is to be followed by the free use of a strong infusion of coffee. According to Dr Garrod, purified animal charcoal is an ‘excellent antidote’ to many of the alkaloids, including those above enumerated, when taken in poisonous doses; as it not merely absorbs them, but, for the most part, renders them inert. To be serviceable it should be recently prepared and fresh-burnt; and should be given in doses of about an ounce at a time, diffused in warm or tepid water, and frequently repeated. The vomiting which follows its use, owing to the warm water, proves advantageous; but after a sufficient time may be lessened by employing less water, or cooler or even cold water. Drowsiness, if