The poison of the common toad acts as a paralyzant upon the heart and on the spinal marrow[155]; that of the common frog possesses similar properties. The poison of the tritons is quite analogous to that of the toads; it contains a lecithin hydrolyzable by water with the formation of alanin, formic acid, and alpha-isocyanopropionic acid. [155] P. BERT: _Compt. rend. de la Soc. de Biologie_, 1885, p. 524. Zalnosky[156] isolated from the glands of the skin of the salamander a white, thick, bitter and alkaline liquid poison, containing a highly poisonous alkaloid, _salamandrine_, or _samandarine_, which acts on the brain, the medulla, and the spinal cord, and which has the formula C{54}H{60}N{2}O{5}; it is a strong base and yields crystallizable salts. [156] _Bull. Soc. Chim._ [2], VI, p. 344. =Fish-poisons.=[157]--Very little accurate knowledge is extant regarding these. Many fish are poisonous, and among them are the synanceia, found in the Indian Ocean between the Netherland Isles and New Caledonia; considerable numbers are found in the neighborhood of the latter locality. These fish are provided with spiny rays which are in direct communication with a poisonous system having its seat in the dorsal fin. The prick of one of the spiny rays of this fish may under certain circumstances result fatally, and in every case it causes a rapid and painful gangrene. [157] BOFFORD: _Thèse de doctorat en Médecine--Les Poissons venimeux_, Paris, 1889; O. ARCOS: _Thèse de doctorat--Essais sur les accidents causés par les poissons venimeux_, Paris, 1887. From the reservoir the poison is conducted to the sharp extremity of the spines by a deep channel with which each spiny ray is provided; the animal has 26 poison-sacs, two for each ray, and the sacs burst when the corresponding sting is in any manner compressed. The poison is an odorless liquid having a slight styptic or acidulous taste, and exhibiting a bluish fluorescence; it rapidly becomes turbid. The weevers, which are numerous on the shores of the Mediterranean Sea, and which are also met with in the northeastern portion of the Atlantic Ocean, are likewise very dangerous, which explains their popular names "viper-weever," "spiderweever," etc. These fish are provided with a double set of poisonous apparatus, the one opercular, which is the more dangerous, and the other dorsal. The opercular spine has a double channel in connection with a conical cavity hollowed out in the base of the opercular bone. The bottom of this cavity is provided with special cells which secrete the poison. The dorsal glands have a similar structure. The poison of the weever is a liquid, limpid when the fish is alive, and turbid when dead; it has a slight bluish fluorescence, is neutral in reaction, and is coagulated by acids and bases. It acts as a paralyzant, its action being exerted on the medulla and spinal cord; it retards the heart's action.