PROPERTIES.--A colorless or pale yellow, and strongly refractive liquid, having a very pungent and acrid odor and taste. Freely soluble in alcohol, ether or carbon disulphide, the solution being neutral to litmus paper. Specific gravity 1.013 to 1.020. ACTIONS.--Is irritant or counter-irritant, rubefacient, vesicant or suppurant, according to the manner in which it is used; it acts much quicker than cantharides, but its action is not so prolonged; the paste made with water and rubbed into the skin of horses, produces its effects within twenty minutes; in two to six hours vesication occurs, pustules may occur where the paste is used very strong or closely repeated, or too much has been used. The volatile oil of mustard is a very powerful vesicant and acts very quickly. USES.--It is used as a counter-irritant in laryngitis, pharyngitis, bronchitis, pneumonia and pleurisy, or wherever a counter-irritant is indicated; applied in the early congested stages it lessens the pain and relieves difficult breathing, besides reflexly limiting the amount of blood in the parts; it thus limits or decreases the inflammatory action; also useful in the exudative stages of these diseases; to promote the absorption of the exudate and thus hasten resolution, or where these diseases remain dormant; also arouse a depressed nervous system and reflexly stimulates the heart; can be used in spinal diseases or in congestion of the kidneys. It acts best when applied and left on 20 or 30 minutes, then washed off and repeat in an hour or two; also used in acute indigestion, applied to the abdomen; also in colic, enteritis and peritonitis; in phlebitis mustard can be used, but a cantharides blister is better. In making a mustard plaster, take the pure powdered mustard and gradually pour in warm water (not hot); can also be made with cold water or vinegar; rub in with moderate friction. As an emetic for dogs one to two teaspoonfuls in one or two ounces of warm water is very effective. SODIUM BICARBONATE--BICARBONATE OF SODA ORIGIN.--Bicarbonate of soda may be obtained by exposing crystals of sodium carbonate to carbonic anhydride, or by the interaction of sodium chloride and ammonium bicarbonate. PROPERTIES.--Bicarbonate of soda is a white, opaque powder, odorless and having a cooling, mildly alkaline taste. It is permanent in dry, but slowly decomposes in moist air. Soluble in twelve parts of water at 15° C. (59° F.); above this temperature the solution gradually loses carbon dioxide, and at boiling heat the salt is entirely converted into normal carbonate, insoluble in alcohol. ACTIONS.--Antacid, peristaltic stimulant, carminative, alterative and mildly anodyne externally. It also increases fluidity of and secretion of gastric juice.