192 THE ANALYST. ABSTRACTS OF PAPERS PUBLISHED IN OTHER JOURNALS. FOODS AND DRUGS ANALYSIS. Rapid Detection of Formaldehyde in Articles of Food. C. Arnold and C. Mentzel. (Chem. Zeit., 1902, xxvi., 246.) - A little phenylhydrazine hydro- chloride is dissolved in 3 to 5 C.C. of the cold liquid which is to be tested, and 2 to 4 drops (not more) of a 5 to 10 per cent. solution of sodium nitroprusside are added; then 8 to 12 drops of 10 to 15 per cent. alkali hydroxide are run in one at a time, when, according to the amount of formaldehyde present, a blue or blue-gray colour appears immediately, which is permanent for some time. In the case of fats, 5 to 10 grarnrnes are shaken at the melting-point with 10 C.C. of 80 to 95 per cent. alcohol, cooled, the solution filtered through a moist paper, and examined as before.Raw or boiled milk, containing 0.015 gramme of formaldehyde per libre, gives a distinct green; pure milk is only tinted yellow. 0.05 gramme per litre yields a fine blue. Raw chopped flesh, saturated with a 0-5 per cent. solution of formaldehyde, was extracted with double its volume of hot water ; the expressed and filtered liquor gave the reaction well, With fats the test indicates 0.3 gramme per kilo. A still more delicate reaction is given by substituting potassium ferricyanide for the nitroprusside ; this develops an intense scarlet in presence of formaldehyde, permanent for a day. Unlike the former test, this only succeeds in alcoholic liquids when enough water to hold the ferricyanide in solution is added. The second reaction is not to be recommended for the examination of milk ; on flesh it ia only to be used if the material ie not reddened by blood-pigments.In all other C&S98 it may be employed if the first test fails by excessive dilution. this ineufficient ground. It also succeeded after keeping the meat for a day. F. H. L. * An excellent cider made by one of the leading manufacturers was disquaIified some years eince onTHE ANALYST. 193 The Detection of Aloes in Pharmaceutical Preparations. E. L6ger. (Journ. Pharm. Chim., 1902, xv., 335.)-Ide?zti$cation of the Type of Aloes.-In order to identify aloes and to distinguish between those of the type of Cape aloes and those of Barbadoes or Curagoa, the author makes use of Klunge's reaction in the following manner : A solution of 0.5 gramme of aloes in 100 C.C.of hot water is rapidly cooled in a current of cold vrater and filtered from the deposited resin, the filtration being accelerated by the addition of a little powdered talc. The following tests are then applied to the clear yellow filtrate : 1. A few decigrammes of sodium peroxide are introduced little by little into 20 C.C. of the liquid, previously heated to 80" C. An immediate evolution of oxygen occurs, and the liquid becomes brown, subsequently changing to bright cherry-red on the further addition of peroxide. The author has identified various substances in the products of the reaction, but attributes the red coloration to the presence of the do-emodin of Tschirch and Oesterle (Ber. d. d. Phurm. Ges., viii., 174; Archiv, der Pharm., ccxxxvii., 01).2. A second portion of 20 C.C. of the filtrate is treated with 1 drop of a saturated solution of copper sulphate, which causes the yellow colour to become darker. One gramme of pure crystallized sodium chloride is next introduced, and then 10 C.C. of 90 per cent. alcohol, which dissolves the flocculent precipitate produced by the salt. With Socotrine and Cape aloes a vinous red colour is obtained, which gradually fades, until after an hour the liquid has become yellow, and shows no further change. In the case of Barbados and Curaqoa aloes, however, a bright, currant-red coloration is obtained, which does not disappear even after standing for twelve hours. The author has found that this reaction is due to a special rtloin, which he terms barb- aloin, in the latter varieties of aloes.Both of the above reactions are very sensitive, the first being obtained with solutions containing only 0.1 per cent. of aloes. Where the coloration is faint, the liquid should be acidified with hydrochloric acid and extracted with ether, and the ethereal solution of emodin shaken with 2 to 3 C.C. of water, rendered alkaline with sodium hydroxide, when a bright red colour will be obtained. Detection of AZoes.-For the detection of aloes in pharmaceutical preparations the first (sodium peroxide) reaction is recommended. It frequently happens, however, that other drugs are also present, such 8s rhubarb, which contains chryso- phanic acid (dioxymethylanthraquinone), an emodine (trioxymethylanthraquinone), and rheine (tetraoxymethylanthraquinone), which dissolve in sufficient quantity to falsify the results.The presence of oxymethylanthraquinones can be detected by adding a small quantity of sodium hydroxide solution, with which they give an immediate red coloration, whilst the solution of pure aloes remains yellow. If the red colour be obtained, a slight exceas of subacetate of lead is added to the solution to precipitate the oxymethylanthraquinones ; or the following method of separation may be employed : Fifty C.C. of the filtered solution of 1 gramme of aloes in 100 C.C. of water are treated with 20 C.C. of a 5 per cent. solution of alum, then with ammonium hydroxide in excess, and lastly with acetic acid until the liquid is just acid. Twenty C.C. of the clear filtrate tested with sodium peroxide gives the194 THE ANALYST.aloes reaction clearly, whilst rhubarb extract treated in the same way gives only a faint peach coloration. As a general rule, however, the author recommends the precipitation with sub- acetate of lead, which he shows gives good results with mixtures of aloes with Cascara sagrada and with Rhainnus fravzgula. C. A. M. On the Reactions for the Identification of Certain Drugs. E. Bourquelot. (Jozun. Pharm. Chiin., 1902, XV., 342-345.)--A loes.-Klunge’s reaction (see preceding abstract) having been shown to be one of oxidation, the author has made experiments to determine whether the same red coloration could be obtained by the action of oxidizing enzymes. For this purpose he used a 50 per cent, glycerin extract of Russzda delica, and obtained a pronounced purple-red colour on adding 10 to 20 drops of this extract to 20 C.C. of a solution of aloin (1 : 500).As in the case of Klunge’s reaction, the intensity of the coloration obtained diminished on recrystal- lization of the aloin, until eventually there wa8 no reaction, owing to the elimination of the barbaloin. Tyrosi?ze.-Hirschsohn’s reagents for aloin (copper sulphate and hydrogen peroxide) also react with tyrosine, a brown coloration being obtained on heating the solution with 1 drop of a 1 per cent. solution of copper sulphate and 2 drops of hydrogen peroxide solution. Loganine-the glucoside discovered by Dunstan and Short-is present in tinctures of nux vomica and St. Ignatius’ bean. The residue left on evaporating a few drops of the tincture in a porcelain basin, and warmed with 3 drops of dilute sulphuric acid (1 : 3), assumes a reddish-violet colour. Preparations of 0pium-h order to identify the presence of meconic acid, 2 C.C. of the tincture are mixed with 4 C.C. of water and a few drops of hydrochloric acid, the mixture shaken with ether, and the ethereal extract shaken with 2 to 3 C.C. of water and a drop of ferric chloride, a red colour being produced in the aqueous layer. Ti?zctz6re of Cachou.-In the new German Pharmacopeia this is stated to give a deep red colour when heated with potassium chromate solution. As the tincture itself is very dark, the author modifies the test by boiling together 20 C.C. of water, 10 drops of the tincture, and 5 drops of potassium chromate solution (1 : 20), a cherry red colour being immediately produced. C. A. M.