_Allen’s Method._--Boil the coffee in 10 parts of water. When perfectly cold add to it a little sulfuric acid, then a strong solution of potassium permanganate, drop by drop, with constant shaking, till the liquid is almost decolorized; strain or decant and add to the solution a solution of iodin. If 1 per cent or more of starch is present, a blue coloration will be produced. CHICORY _Rimmington’s Test._--Boil a portion of the sample with water which contains a little sodium carbonate; decant, wash and treat the residue with a weak solution of bleaching powder for several hours. The solution will be decolorized. The coffee will be at the bottom as a dark layer while the chicory will be a light layer above it. _Albert Smith’s Test._--Boil 10 grams of the sample in 250 cc. of water; strain and add basic lead acetate in slight excess. A precipitate forms, and when it has settled the supernatant liquid will be colorless if the coffee is pure, but more or less colored if chicory is present. TEA Tea is adulterated by the substitution of inferior grades for those of better quality, by the addition of exhausted leaves and foreign leaves, by the use of coloring matter or “facing” such as Prussian blue, indigo, or turmeric to color green tea, and sometimes graphite to color black tea. Foreign astringents (generally catechu) are added to conceal the presence of exhausted leaves. An imitation tea, “lie tea,” is made of the stems and dust with mineral matter, and some starch or gum to hold these together. FOREIGN LEAVES Though there are several chemical tests for foreign leaves, none are as satisfactory as a microscopical examination. Soften the leaves by soaking in hot water, unroll carefully and examine with a hand lens or low power of the microscope. Compare with a genuine leaf--the shape, margin, and venation. EXHAUSTED TEA LEAVES Sometimes such leaves may be detected by a physical examination. They are often more or less unrolled and broken on the edges. But the only certain way of ascertaining their presence is to determine the soluble ash which is from 2.5 to 4 per cent in pure tea and usually less than 0.8 per cent in exhausted tea. LIE TEA This imitation tea is easily detected by pouring hot water over the leaves. If they are artificial, they will break down into the fragments of which they were made. FACING Organic coloring matter may be detected by the same method used for detecting such colors in coffee. CATECHU _Hager’s Test._--Boil a little of the tea in water, and add to the extract an excess of lead monoxid. If the tea is pure the addition of a solution of silver nitrate produces only a slight grayish precipitate, but when catechu is present a yellow flocculent precipitate forms. A FEW OF THE BEST BOOKS ON FOOD ANALYSIS ALLEN, A. H., Commercial Organic Analysis, 1898. Price, $29.50. BLYTH, A. W., Foods, their Composition and Analysis, 1903. Price, $8.40.