Argentum. Silver. 



^rgenti Nitras. Dose, 1/4- K gr.; 15-30 __ . 

 Colourless crystals. Soluble 1 in less than 1 of water; slightly soluble 

 in alcohol; soluble in ether and glycerin. 



Incompatibles, most inorganic salts and many organic preparations, 

 ^rgenti Nitras Induratus. Toughened Caustic. Opaque 

 white cylindrical bars. 95; Potassium Nitrate, 5. Fused and poured 

 into moulds. 



'Argenti Nitras Mitigatus. Mitigated Caustic. Resembles 

 the above 33; Potassium Nitrate, 66. Fused and poured into moulds. 



3 Argenti Oxidum. Dose, ^-2 grs. ; 3-12 cgms. 

 A brown powder insoluble in water and alcohol. 



Incompatibles, forms explosive mixtures with sulphur, sulphides., 

 phosphorus, tannic acid, creosote, and many other organic substances. 



ArmoracicB Radix. Horse-radish Root. The root of Cochlearia 

 Armoracia: nearly cylindrical, 24 inches or more in length, >-! inch 

 in diameter, externally pale yellow, internally white, odour pungent 

 when bruised or scraped, taste pungent. 



Spiritus Armoraciae Compositus. Dose, 1-2 fl. drs. ; 4-8 c.c. 

 The root macerated with water, to which Bitter Orange Peel, Nutmeg, and 

 Alcohol are added; and distilled. 



Arnica Rhizoma. Arnica Rhizome. The dried rhizome and roots 

 of Arnica montana. The horizontal, cylindrical, dark-brown rhizome 

 (rootstock) is 1-2 inches long, 1/6-1/4 inches in diameter, curved and rough 

 with leaf scars above and roots or their scars below; odour faintly aromatic, 

 taste bitter and acrid. 



Tinctura Arnicae. 20; alcohol 70%, 100: by percolation. Used 

 externally. 



ARSENIUM, ARSENIC. 



Arseniosum. Arsenious Anhydride. (Arsenicums. Ar- 

 senic. White Arsenic. Arsenious Acid.) Dose, 1/60-1/15 gr.; 1-4 mgms. 

 Arsenious anhydride, As 4 Oe, occurs as a heavy white powder, or as strati- 

 fied partially crystalline masses; tasteless, odourless, in aqueous solution 

 slightly acid in reaction. Soluble 1 in 20 of hot water, 1 in 60 of cold; 1 

 in 8 of glycerin; moderately soluble in solutions of the hydrates and car- 

 bonates of the alkalies and in solutions of hydrochloric acid. 



Incompatibles of arsenious anhydride and of arsenites, most metallic 

 salts in solution, potassium iodide (1 dr. of potassium iodide in 1 dr. of 



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