Agaricus (Amanita muscaria).

Related entry: Boletus

The fungus Amanita muscaria, Persoon; (Agaricus muscarius, Linné.) (Nat. Ord. Fungi.) An extremely poisonous fungus found in the pine forests of Europe.
Common Name: Fly Agaric.

Principal Constituents.—Muscarine, a deadly alkaloid, and pilzatropin, its physiologic opposite.
Preparations.—1. Tinctura Agarici, Tincture of Agaricus (Fresh fungus, 1 ounce; strong alcohol, 16 fluidounces). Dose, 1/30 drop.
2. Muscarine. Dose, 1/30 to 1/12 grain.
Action and Toxicology.—The chief toxic action of agaricus is probably due to muscarine, which produces ptyalism, weeping, vomiting, depressed circulation, difficult breathing, muscular weakness, minutely contracted pupils, tetanic contraction of the viscera with subsequent relaxation of the bowels, when violent peristalsis takes place, paralysis and death. Muscarine is the direct antagonist to atropine.

Closely allied to Agaricus is Amanita phalloides, Fries or Death Cup. Common in the United States and the cause of many fatal poisonings. Gastro-enteritis with choleraic diarrhoea occurs, with death within two to four days. It contains muscarine and a toxalbumen phallin, both of which are deadly agents. While salt abstracts the latter, there is no known antidote after it has been absorbed.

Therapy.—Agaricus is seldom used, but possesses undoubted power over the secretions and the nervous system. The chief uses that have been made of it, and for these even the muscarine sulphate or nitrate have been mostly employed, are in colliquative night-sweating from debilitating diseases, and profuse sweating in the daytime; and to restrain the excess of urine in polyuria, or so-called diabetes insipidus.

Scudder suggested a tincture of the fresh fungus for "involuntary twitching of the muscles of the face, forehead, and even of the eyes, so that objects are not well seen because they seem to move; drawing of the tissues of the forehead and nose; pressing pain in the occiput and an inclination to fall backward." Webster thought it useful in typhoid conditions and spinal irritation when there is "tremor, restlessness, and desire to get out of bed." These indications are of homeopathic origin and have been but little followed by Eclectic practitioners.

Muscarine is used in atropine and belladonna poisoning, sometimes being employed in place of eserine (physostigmine).

The Eclectic Materia Medica, Pharmacology and Therapeutics, 1922, was written by Harvey Wickes Felter, M.D.