340 ACIDS. 



acid properties as well as of the gas. Muriatic acid has been given 

 as a refrigerant and tonic, in typhus, in malignant sore throat, 

 and in some obstinate cutaneous eruptions. The dose is from ten 

 to thirty drops. 



Sp. 3. Sulphuric Acid.— Native or pure Sulphuric Acid is 

 said to he found in a concrete state, in the cavities of some volcanic 

 mountains ; it is also observed trickling from the roofs of caves in 

 iEtna, near Aix in Savoy, and various places in Italy; but as an 

 article of commerce it is usually obtained by burning a mixture of 

 about eight parts of sulphur, and one of nitre in close leaden cham- 

 bers, containing water, by which the fumes, as they rise, are succes- 

 sively condensed ; and the acid is procured in a concentrated state 

 by evaporation of the solution. The hydro-sulphuric acid, or oil 

 of vitriol, is a colourless, oily fluid, of a specific gravity, when con- 

 centrated of 1-85. It boils at 620°, and freezes at 15°. It is 

 acrid, extremely caustic, and quickly decomposes animal and vege- 

 table substances. It rapidly absorbs oxygen from the atmosphere, 

 and may be combined with water in any proportion. Though 

 largely diluted its taste is intensely sour, and it instantly reddens 

 the vegetable blues. It readily combines with the alkalies, and with 

 alumine, and with some of the metals forms soluble native salts, 

 all of which, except the sulphate of soda, are precipitated from 

 their solutions by carbonated alkalies. Medicinally, this acid is a 

 useful refrigerant, antiseptic, and tonic. As an astringent, it is 

 frequently prescribed to check the discharge of blood in haemoptysis, 

 and the colliquative sweats in hectic fever. It is also used in 

 menorrhagia and diabetes; and as a tonic in dyspepsia, low 

 typhoid fevers, convalescences, cutaneous eruptions, and confluent 

 small-pox. It is a very common adjunct to gargles in cynanche ; 

 and as an external application, mixed with lard in the proportion 

 of half a drachm to an ounce, it has been used with advantage in 

 scabies. The dose of the diluted acid {Acidum Sulphiricum 

 dilutum) may be from 10 to 30 drops in any of the common 

 bitter infusions or decoctions. 



Sp. 4. Nitric Acid. — This acid has not been found in a pure 

 state in nature, but is generally obtained from the nitrate of 

 potass, by the action of sulphuric acid. Nitric acid is a colour- 



