Origin. - It is found in great quantities imbedded in clay and sand in certain districts of Chili and Peru.

Description and Properties. - Colorless, transparent, rhombohedral crystals, odorless, having a cooling, saline, and slightly bitter taste; deliquescent in moist air. Soluble in 1.3 parts of water and in about 100 parts of alcohol. Sodium nitrate should be kept in well-stoppered bottles.

Dose. - 1/2-1 ounce (15.5-31.0 Gm.) [15 grains (1 Gm.), U. S. P.].

Physiological Action. - The action of the salt resembles closely that of potassium nitrate, though it is much feebler than the latter drug, particularly being less depressing to the heart muscle and in possessing greater purgative properties.

Therapeutics. - Externally and Locally. - A solution of the salt possesses some power as a solvent of false membranes, and has been used in the form of a spray to diminish fibrinous exudations in the pharynx and larynx.

Internally. - It may be employed for the same purpose as the potassium nitrate and has been advantageously adopted as a laxative in diarrhea and dysentery.

Administration. - Sodium nitrate is best given dissolved in a large quantity of water.