§ 624. The secretion of the skin of the common toad contains methylcarbylaminic acid, carbylamine, and, according to Fornara, an alkaloid which is soluble in alcohol, and to which the name of phrynine has been applied; its action is toxic on all animals experimented upon, save toads. Administered subcutaneously to frogs, it has a digitalis-like action, causing rapid paralysis of the heart, and the breathing soon after ceases; the muscles become early rigid.
II.—The Poison of the Scorpion.
§ 625. There are several species of scorpions. The small European variety (Scorpio europæus) is found in Italy, the south of France, and the Tyrol; the African scorpion (Bothus afer, L.), which attains the length of 16 cm., is found in Africa and the East Indies; Androctonus bicolor in Egypt; and the Androctonus occitanus in Spain, Italy, Greece, and North Africa.
In the last joint of the tail the scorpion is provided with a poisonous apparatus, consisting of two oval glands, the canal of which leads into a round bladder, and this last is connected with a sting. When the sting is inserted, the bladder contracts, and expels the poison through the hollow sting into the wound. The smaller kinds of scorpion sting with as little general effect as a hornet, but the large scorpion of Africa is capable of producing death. There is first irritation about the wound, and an erysipelatous inflammation, which may lead to gangrene. Vomiting and diarrhœa then set in, with general weakness and a fever, which may last from one to one and a half days; in the more serious cases there are fainting, delirium, coma, convulsions, and death. According to G. Sanarelli[632] the blood corpuscles of birds, fishes, frogs, and salamanders are dissolved by the poison; only the nucleus remaining intact; the blood corpuscles of warm-blooded animals are not affected.
[632] G. Sanarelli, Bollet. della Soc. della sez. dei cult. delle Scienze med., v., 1888, 202.
Valentin made some experiments on frogs with the Androctonus occitanus. He found that soon after the sting the animal remains quiet, but on irritation it moves, and is thrown into a transitory convulsion; to this follow twitchings of single muscular bundles. The frog is progressively paralysed, and the reflex irritability is gradually extinguished from behind forwards; at first the muscles may be excited by electrical stimuli to the nerves, but later they are only capable of contraction by direct stimuli.