bodies the case is different so that upon the whole it is safest to secure complete decoloration. The temperature must be maintained at the boiling-point of the acid or near thereto since at a lower temperature, for instance from 100° to 150°, the formation of ammonia is incomplete. Since all organic substances of whatever kind are dissolved by the boiling acid the previous pulverization of the material need be carried only far enough to secure a fair sample. Many substances give up practically all their nitrogen as ammonium sulfate when heated with sulfuric acid as, for instance, urea, asparagin, and the glutens. In most of the other organic bodies fully ninety per cent of the nitrogen are likewise secured as the ammonium salt. In the aromatic compounds, or even in the form of amid in anilin salts, the nitrogen is more resistant to the action of sulfuric acid. In the alkaloids where the nitrogen is probably a real component of the benzol skeleton the formation of ammonia is very incomplete. But even in the cases where the conversion of the nitrogen into ammonia is practically perfect it is advisable to finish the process by completing the oxidation with potassium permanganate. The permanganate should be used in a dry powdered form and added little by little to the hot contents of the digestion flask, the latter being held in an upright position and removed meanwhile from the lamp. When carefully performed there is no danger of loss of ammonia although the oxidation is, at times, so vigorous as to be attended with evolution of light. The permanganate must always be added in excess and until a permanent green color is produced. The flask is then gently heated for from five to ten minutes over a small flame, but this is not important. The heating must not be too strong or else a strong evolution of oxygen will take place with a consequent reduction of the manganese compound. When this happens the liquid again becomes clear and there is a loss of ammonia.