[116] There is a common liniment for horses used in stables, and popularly known as “white oil.” It contains 1 part of ammonia, and 4 parts of olive or rape oil; not unfrequently turpentine is added. Another veterinary liniment, called “egg oil,” contains ammonia, oil of origanum, turpentine, and the yelks of eggs. _The carbonate of ammonia_ is also caustic; it is considered to be a compound of acid carbonate of ammonium, NH₄HCO₃, with carbamate of ammonium, NH₄NH₂CO₂. It is in the form of colourless, crystalline masses; the odour is powerfully ammoniacal; it is strongly alkaline, and the taste is acrid. It completely volatilises with heat, is soluble in water, and somewhat soluble in spirit. The officinal preparation is the “_spiritus ammoniæ aromaticus_,” or aromatic spirit of ammonia. It is made by distilling in a particular way ammonic carbonate, 4 ozs.; strong solution of ammonia, 8 ozs.; rectified spirit, 120 ozs.; water, 60 ozs.; volatile oil of nutmeg, 4½ drms.; and oil of lemon, 6½ drms. Aromatic spirit of ammonia is a solution in a weak spirit of neutral carbonate, flavoured with oil of lemon and nutmeg; the specific gravity should be 0·896. _Smelling salts_ (_sal volatile_) are composed of carbonate of ammonia. § 93. =Statistics.=--Falck has found throughout literature notices of thirty cases of poisoning by ammonia, or some of its preparations. In two of these it was used as a poison for the purpose of murder, and in eight with suicidal intent; the remainder were all accidental. The two criminal cases were those of children, who both died. Six out of eight of the suicidal, and twelve of the twenty accidental cases also terminated fatally. Ammonia was the cause of 64 deaths (39 male, 25 female) by accident and of 34 (18 male, 16 female) by suicide, making a total of 98 during the ten years 1883-1892 in England and Wales. At present it occupies the seventh place among poisons as a cause of accident, the ninth as a means of suicide. § 94. =Poisoning by Ammonia Vapour.=--Strong ammoniacal vapour is fatal to both animal and vegetable life. There are, however, but few instances of poisoning by ammonia vapour; these few cases have been, without exception, the result of accident. Two cases of death are recorded, due to an attempt to rouse epileptics from stupor, by an injudicious use of strong ammonia applied to the nostrils. In another case, when hydrocyanic acid had been taken, there was the same result. An instance is also on record of poisonous effects from the breaking of a bottle of ammonia, and the sudden evolution in this way of an enormous volume of the caustic gas. Lastly, a man employed in the manufacture of ice, by means of the liquefaction of ammonia (Carré’s process), breathed the vapour, and had a narrow escape for his life.