Nitrate of silver 1·0 part, hot distilled water 3·6 parts, mucilage, previously rubbed with sap-green, 1·0 part. With this is sold a “pounce,” or preparation consisting of a coloured solution of sodic carbonate. Another preparation is very similar, but with the addition of ammonia and some colouring matter, such as indigo, syrup of buckthorn, or sap-green. A third is made with tartaric acid and nitrate of silver, dissolved in ammonia solution, and coloured.
Redwood’s Ink consists of equal parts of nitrate of silver and potassic bitartrate, dissolved in ammonia, with the addition of archil green and sugar; according to the formula, 100 parts should equal 16·6 of silver nitrate.
Soubeiran’s Ink is composed of cupric nitrate 3, argentic nitrate 8, sodic carbonate 4, and the whole made up to 100 parts, in solution of ammonia. In one of Mr. Reade’s inks, besides silver, an ammoniacal solution of a salt of gold is used.
§ 823. Medicinal Dose of Silver Compounds.—The nitrate and the oxide of silver are given in doses from ·0162 to ·1296 grm. (1⁄4 grain to 2 grains). Anything like ·1944 to ·2592 grm. (3 or 4 grains) would be considered a large, if not a dangerous dose; but nothing definite is known as to what would be a poisonous dose.
§ 824. Effects of Nitrate of Silver on Animals.—Nitrate of silver is changed into chloride by the animal fluids, and also forms a compound with albumen. Silver chloride and silver albumenate are both somewhat soluble in solutions containing chlorides of the alkalies, which explains how a metallic salt, so very insoluble in water, can be absorbed by the blood.
The action of soluble salts of silver on animals has been several times investigated. There appears to be some difference between its effects on warm and cold-blooded animals. In frogs there is quickly an exaltation of the functions of the spinal cord, tetanic convulsions appear, similar to those induced by strychnine; later, there is disturbance of the respiration and cessation of voluntary motion.
The first symptoms with dogs and cats are vomiting and diarrhœa; muscular weakness, paralysis, disturbance of the respiration, and weak clonic convulsions follow. Rouget, as well as Curci, considers that the action of silver is directed to the central nervous system; there is first excitement, and then follows paralysis of the centres of respiration and movement. Death occurs through central asphyxia. According to the researches of F. A. Falck, subcutaneous injections of silver nitrate into rabbits cause a fall of temperature of 6·7° to 17·6°, the last being the greatest fall which, in his numerous researches on the effect of poisons on temperature, he has seen.
Chronic poisoning, according to the experiments of Bogoslowsky on animals, produces emaciation, fatty degeneration of the liver, kidneys, and also of the muscles—a statement confirmed by others.
§ 825. Toxic Effects of Silver Nitrate in Man—(1) Acute Poisoning.—This is very rare. Orfila relates an attempt at suicide; but most of the cases have been accidental, and of these, in recent times, about five are recorded, mostly children. The accident is usually due to the application of the solid nitrate to the throat, as an escharotic, the stick breaking or becoming detached, and being immediately swallowed; such an accident is related by Scattergood.[901] A piece of silver nitrate 3⁄4 inch long, slipped down the throat of a child, aged fifteen months—vomiting immediately occurred, followed by convulsions and diarrhœa; chloride of sodium was administered, but the child died in six hours. In other cases paralysis and an unconscious state has been observed.