ANALYTICAL CHEMISTRY. Analytical Chemistry. The Iodine and Starch Reaction. By E. PUCHOT (Conzpt. vend. lxxxiii 225-226) .-The sensitiveness of the iodine and starch reaction is greatly impaired by the presence of certain organic nitro- genous bodies. Thus albumin introduced into t,he water which holds iii suspension iodide of starch causes the disappearance of the colour ; and if albumin be mixed with a solution of starch the addition of a saturated aqueous solution of iodine produces no coloration unless the iodine be added in great excess. As albumin added to an aqueous solution of iodine causes the colour to vanish there probably is in the above-described cases a direct combination between the iodine * This is true only at teiiiperatures not exceeding 15".Subsequent experiments at 25" showed that the yeast developed in solutions containing as much as 10.6 per cent. of alcohol is not quite pure. LO8 ABSTRACTS OF CHEAIICAL PAPERS. and the albumin. If a little albumin be mixed up with starch in rz mortar and iodine drop by drop be allowed to fall upon the mixture each drop produces a temporary blue stain which disappears as the liquid by spreading meets with a sufficient quant,ity of albumiu. 1%.1%. Detection of Traces of Phosphoric Acid in Toxicological Researches. By F.S E LMI (Gaxxetta chimica itnliana vi 34-35).-The method consists in bending the cxtremity of a platinum wire into a ring dipping it into the liquid suspected to contain phosphoric acid and then inserting it into the centre of a hydrogen flame at a point somewhat nearer to the orifice than to the apex of the flame.The minutest trace of phosphoric acid immediately communicates a green tinge to the flame. In using this test sodium must be absent,* and the phosphoric acid in the free state. C. E. G. Dittmark Method of Determining the amount of Chromium in Chrome Ores. (DingZ. yolyt. J. ccxxi 450).-!L’his method is based on the knowledge of the fact that powdered chromium ores are readily dissolved in a flux consisting of B parts of borax fused toge- ther with 3 parts of alkaline carbonates. The mixture formed absorbs oxygen during the fusion and also while in contact with the air and this results in a conversion of the oxide of chromium to a chromate. 0.5 gram of the ore is fused with 5-6 grams of the above- mentioned flux in a covered crucible for about five miiiutxs.?’he lid of the crucible is then removed and the mass heated very strongly ~rithconstant stirring until the whole of the ore has been dissolved %\-lienthe fusion is still continued for about three-quarters of an hour. The fused mass is digested with water heated over a water-bath with the addition of a few drops of alcohol so as to reduce any manganates if present; the liquid is filtercd and the residue washed with hot water. The filtrate contains the whole of the chromium present in the ore in the form of a chromate which is determined according to Penny’s method by dissolving a certain quantity of iron wire in hot dilute sulphuric acid cooling the solution very quickly and adding the chromate.The mixture is then titrated back with potassium bichromate. Experiments have shown that one fusion suffices to dissolve the whole of the chromium present in the ore ; the utmost difference when two fusions were made was not more than 0.3 per cent. of oxide. Althougli the platinum crucibles employed showed no signs of alte-ration the residue after fusion gave a notable quantity of a platinum salt when dissolved in dilute sulphuric acid. It is therefore not adi&,ble to simplify the above method by dissolving the whole fused mas4 in dilute acid and then titrating the solution. D. €3. A new Chemical Test for Alcohol. By EDMUND W. DAVY (Proceediiays of tlie Boyal Irish Academy [2] ii 579-582) .-A solutioii of 1part of molybdic acid in 10 parts of strong pure sulphuric acid * The difficulty occasioned by the presence of sodium may be overcome by examining the flame with the specfroscope.-iYote by Abstractor..ANALYTlCAL CHEMISTRY. 109 is warmed gently in a porcelain capule and a few drops of the liquid to be tested are allowed to fall gently into the capsule. If alcohol be present a blue coloration becomes apparcnt either imme- diately or after a few moments. This coloration disappears after exposlire to the air but onlyin consequence of absorption of moisture for on evaporation thc colour again appears. This colour is also pro-duced by methyl propyl butyl arid amyl alcohols ether and alde- hyde. The test is especially useful for detecting alcohol in chloroform or in chloral hydrate.Its sensitiveness is so great that alcohol may be detectcd in one drop of a mixture of 1part of alcohol with 1,000 of water. W. R. Rhodeine a New Test for Aniline. By E. JACQUENIN (Cowp. ~enc7. lxxxiii 226-229). -The sensitiveness of the well-known reaction of aniline with hypochlorites is such that one part in 10,000 may be detected. With a greater dilution hypochlorites give orily a very slight brown tint if they produce any visible effect at all. But the author has found that the further addition to the brown or colourless solution of a few drops of a very dilute solution of ammonium sulphide (one drop in 30 cc. of water) develops a mag-nificent rose colour by which so small a proportion as one part of aniline in 250,000 may be recognised.This new colour which is very fugitive and disappears immediately if an excess of sulphide be added the author proposes to designate as s-hodeiqae. He did not obtain similar results with oxidising or reducing reagents other than those above-named nor did toluidine &c. produce any such effects. R. R. Phyllocyanin as a Reagent. By G . PEL LAG RI (GnxPtia chimica italicma vi 35-38) .-The blue colouring matter of flowel's p.hy110-eyanin is extremely sensitive to minute traces of free alkali and although the blue solution cannot be preserved yet when a small quantity of sulphuric acid is added the red solution thus produced may be kept for a long time without' undergoing alteration. The quaxitity of acid added should not be so large as to give a distinct red colour but merely enough to change it to a dark purple intermediate between the blue and red.In this state it is capable of showing dis-tinctly the alkaline reaction caused by the presence of Smmonia in rain-water or by the plumbic hydrate in water which has been in contact with metallic lead. Added to a solution of one part of potassium hydrate iu 1,200,000 parts of water it produces a per-manent blue colour whilst with a solution in 200,000 parts of water a permanent green is obtained. It is therefore a much more delicate test than litmus which scarcely gives any reaction with the last-mentioned solution. Paper prepared with a solution of phyllocjranin mast be kept in well-closed vessels ; for although unaEected in a vacuum or by air which has been exposed over sulphuric acid yet when it is exposed freely to the air the ammonia present in it turns the colour blue.The phgllocganin is best obixained from the iris the violet or the purple verbena by treating the petals with a small quantity of warm ABSTRACTS OF CHEMICAL PAPERS. water ; sulphuric acid is then added until it assumes a purpie coiour and the solution is preserved in a closed vessel excluded from the light. c'. E. (3. Determination of Theine in Tea. By B. W. MARKOWNIKOFF (Deut. Chena. Ges. Ber. ix 1312-1313).-15 grams of powdered tea 15 grams of magnesia usta and 500 cc. water are boiled and filtered ; the residue washed with hot water ; and the filtrate after addition of magnesia and sand evaporated to dryness.The residue is ex- hausted with hot benzene which is then evaporated and the residue weighed. Young leaves contain more theine and less ash than old ones. The author believes that the quality of tea does not depend on the quantity of theine but on that of tannic acid esseiltial oils &c. c. s. Modification of the Process for Extracting the Poisonous Alkaloi'ds from the Viscera. By F. SELMI(Gazzetta chiqnicn itaZiana vi 32-34).-As it has been found that the acidulated alcoholic extract containing the alkalo'ids frequently undergoes altera- tion when evaporated in the ordinary way the author concentrates the solution in small portions at a time at about 65" in a porcelain dish accelerating the evaporation by means of a fan.The aqueous liquid thus obtained is filtered concentrated and agitated with ether after the addition of barytn. If the ethereal solution is coloured it must be evaporated mixed with basic acctate of lead exposed to the air for 24 hours and then filtered from the carbonate of lead and the coloured lead lake. The excess of lead is then removed by sulphnretted hydrogen the solution evaporated and the alkaloids again taken up by ether after the addition of baryta ; even then the ethereal solution may contain foreign matters which modify the reactions or impede crystallisation. If however an ethereal solution of tartaric acid be added a white precipitate is formed which usually contains the whole of the alkalo'id as tartrate.In some cases the alkdoi'ds may be pre- cipitated as carbonates by passing a current of dried carbonic anhy- dride into the ethereal solution ; if not on adding about one-third or one-fourth of the volume of distilled water and continuing the passage of the gas the carbonates of the alkaloids are dissolved by the water whilst the foreign matters remain in the ethereal solution. Amylic alcohol extracts may with advantage be treated in a similar manner. The coloured precipitate above mentioned should also be carefully examined suspending it in water and decomposing it by sulphuretted hydrogen. In the case of volatile alkalo'ids the author separates them by dis- tilling them off in the vapour of absolute alcohol and condensing the vapours in a receiver containing an alcoholic solution of tartaric acid. C. E. G.