Tea-extract yields a comparatively large quantity of ammonia when it is boiled with potash and permanganate of potash, and it is probable that this character may prove very valuable also in testing the purity of tea, for which purpose a solution containing about 10 per cent. of solid potash, free from ammonia and nitrogenous matter, is required and easily obtained. Ten grams of this solution of potash is put into a small flask-retort, working in an oil-bath and connected with a small condenser; the whole apparatus to be carefully freed from the last traces of ammonia, which is best accomplished by distilling the water through it, after which from 5 to 10 parts of the tea infusion are poured into the retort, which is then corked up and heated in an oil-bath to 150 C. Having been maintained for a short time at this temperature it is then lifted out of the bath and some pure water poured into the retort, which is again to be heated in the oil-bath. More than half of the water is then distilled over and in this manner the “free ammonia” is obtained from the distillate. When this has been accomplished some of the potash and permanganate solution is added to the contents of the retort and distilled so as to yield a distillate containing “albuminoid ammonia,” the result being as follows in pure teas:— Free ammonia, 0.28 milligrams. Albuminoid ammonia, 0.43 “ ————— Total, 0.71 milligrams. While the extract from a sample of spurious leaves yielded of Free ammonia, 0.20 milligrams. Albuminoid ammonia, 0.295 “ ————— Total, 0.495 milligrams.