Mercuric cyanide, it has been often said, acts precisely like mercuric chloride (corrosive sublimate), and a poisonous action is attributed to it not traceable to cyanogen; but this is erroneous teaching. Bernard[266] declares that it is decomposed by the gastric juice, and hydric cyanide set free; while Pelikan puts it in the same series as ammonic and potassic cyanides. Lastly, Tolmatscheff,[267] by direct experiment, has found its action to resemble closely that of hydric cyanide.[268]
[266] Substances Toxiques, pp. 66-103.
[267] “Einige Bemerkungen über die Wirkung von Cyanquecksilber,” in Hoppe-Seyler’s Med. Chem. Untersuchungen, 2 Heft, p. 279.
[268] Mercury cyanide may be detected in a liquid after acidifying with tartaric acid, and adding a few c.c. of SH2 water and then distilling. S. Lopes suggests another process: the liquid is acidified with tartaric acid, ammonium chloride added in excess, and the liquid is distilled. A double chloride of ammonium and mercury is formed, and HCN distils over with the steam.—J. Pharm., xxvii. 550-553.
Silver cyanide acts, according to the experiments of Nunneley, also like hydric cyanide, but very much weaker.
Hydric sulphocyanide in very large doses is poisonous.
Potassic sulphocyanide, according to Dubreuil and Legros,[269] if subcutaneously injected, causes first local paralysis of the muscles, and later, convulsions.