122 INORGANIC AGENTS 



absorption of exudations (pleural effusions, for example)^ 

 throu<^li their diuretic power. They are also good uric acid 

 solvents. They are sometimes prescribed in fever on account 

 of slight diarphoretic and powerful diuretic properties, but 

 are rarely used in veterinary medicine, in comparison with 

 potassium nitrate, in this condition. 



The salts under consideration stimulate bronchial secre- 

 tion and make it thinner, and are recommended accordingly 

 in bronchitis. They are less efficient than potassium iodide 

 for these purposes in this affection. 



PoTASSii NiTRAS. Potassium Nitrate. KNO, (U.S.cfeB.F.) 



Synonym. — Nitre, saltpetre, E.; nitre prismatique, azo- 

 tate (nitrate) de potasse, Fr.; saltpetersaures kali, kalisal- 

 peter, G. 



Derivation. — Saltpetre is formed in the soil in certain 

 regions and climates and is made artificially, by the putre- 

 faction of animal or vegetable material, in the presence of 

 heat, moisture, oxygen, and alkaline or earthy bases capable 

 of fixing the nitric acid set free in this process, known as 

 nitrification. The natural conditions for nitrification are 

 present in some parts of India, and saltpetre is largely 

 imported from Calcutta. Artificially, nitre beds are made 

 of animal and vegetable matter, wood ashes, and calcareous 

 earth or old plaster from houses. Sodium nitrate is im- 

 ported extensively from Chili, where it occurs as a mineral 

 product, and is used widely in this country in artificial 

 fertilizers. Chili saltpetre may be converted into nitre by 

 treatment with potash. 



Properties. — Colorless, transparent, six-sided, rhombic 

 prisms, or a crystalline powder, odorless and having a cool- 

 ing, saline and pungent taste. Permanent in the air. Sol- 

 uble in 3.8 parts of water ; very sparingly soluble in alcohol. 



Dosc—n. & d, 5 ss.-i. (15.-30.) ; Sh. & Sw., 3 ss.-i. (2.-4.); 

 D., gr.v.-xx. (.3-1.3). 



Action External. — Refrigerant. 



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