III.——Mr Wanklyn discriminates the different alkaloids from the estimation of the ammonia they evolve. His process is as follows:——A small flask with a lateral tube, and connected with a Liebig’s condenser, is charged with about 25 c. c. of an alkaline solution of permanganate potash made by dissolving 200 grammes of caustic potash and 8 grammes of crystallised permanganate of potash in 1 litre of water. A minute quantity of the alkaloid carefully and accurately weighed is now introduced, and the mixture slowly distilled. The most satisfactory results are obtained by treating from 1 to 5 milligrammes of the alkaloid in this way, but quantities so small as 1/10th of a milligram will in skilled hands give accurate results. The ammonia is formed in the distillate by Nesslerising it, as described under WATER ANALYSIS. For all practical purposes the poisonous alkaloids may be divided into four classes: (a) Those which yield from 5 to 2 per cent. of ammonia. (b) Those which yield from 2 to 3 per cent. of ammonia. (c) Those which yield from 3 to 5 per cent. of ammonia. (d) Those which yield a larger quantity than 5 per cent., _e.g._ I. NH_{3} per cent. SOLANINE yields half its nitrogen as Ammonia 0·98 II. MORPHIA yields half its nitrogen as Ammonia 2·98 CODEINE, ditto, ditto 2·87 PAPAVERINE, ditto, ditto 2·50 VERATRIA, ditto, ditto 2·87 III. ATROPIA yields all its nitrogen as Ammonia 5·73 NARCOTINE, ditto, ditto 4·11 STRYCHNIA yields half its nitrogen as Ammonia 5·09 BRUCINE, ditto, ditto 4·32 ACONITE, ditto, ditto 3·50 CONEINE, ditto, ditto 4·60 IV. NICOTINE yields half its nitrogen as Ammonia 10·49 IV. Dr Guy, as well as others, have made researches, having for their object the determination of the exact temperature at which the poisonous alkaloids melt and sublime. A very minute speck of the substance is placed on a porcelain plate or copper disc, and a square or oval of microscope-covering glass is placed over it, supported by a thin ring of glass or any other convenient substance. Heat is then applied to the plate or copper, and the temperature, as indicated by a thermometer at which the substance fuses or volatilises, is carefully noted. CANTHARIDINE sublimes as a white Fahr. Cent. vapour without change of form or colour. 212° 100°