ACTION OF SILVER NITRATE 167 



When applied externally in the pure state to a mucous 

 membrane, or a raw surface, it forms a white coating of 

 coagulated albumin. This coating limits the further action 

 of the salt, so that lunar caustic is always superficial and 

 localized in its effect. Silver nitrate is the caustic in most 

 common use, since it produces a more healthy condition in 

 a granulating wound after its application and separation of 

 the eschar. In acting thus more favorably than other agents 

 of its kind, it may be said to possess a local alterative effect. 

 In dilution, silver nitrate is stimulant, astringent, antiseptic 

 and caustic, according to its strength. 



Internal— Si\\GT nitrate is probably precipitated to a 

 considerable extent by the hydrochloric acid of the gastric 

 juice, as the chloride. Some of it is absorbed, however, 

 possibly in combination with albumin and peptones. Silver 

 is deposited in the tissues in the form of the oxide, causing 

 dark staining of the skin in man. These stains, occurring 

 when silver nitrate comes in direct contact with the skin, 

 can be removed by a solution containing potassium cyanide, 

 2J drachms ; iodine, 15 grains ; and water, 3 ounces. Large 

 doses of silver nitrate cause gastio-enteritis with nervous 

 symptoms — paralysis and convulsions — and death from 

 depression of the respiratory centres. Common salt is the 

 antidote, both externally and internally, forming the in- 

 soluble chloride. In addition to salt, opium and demulcents 

 should be exhibited in acute poisoning. Silver nitrate in 

 medicinal doses has probably a local stimulating, astrin- 

 gent and alterative actioa on the mucous membrane of 

 the stomach ; to a less degree on the bowels. Elimination 

 occurs in part through the agency of the liver and in- 

 testines. A chronic form of poisoning by silver nitrate 

 (argyrism), is seen in man, following its continued use, 

 and is accompanied by pigmentation of the skin, maras- 

 mus, chronic indigestion, with wasting of the testes and 

 mammary glands. A similar condition has been produced 

 in animals, associated with anorexia, weakness, anaemia and 

 emaciation. . 



