ii. 66 ABSTRACTS OF CHEMICAL PAPERS. Analytical Chemistry. The Foundations of Acidimetry and Alkalimetry. A. THIEL (Ber. Deut. Pharm. G‘es. 1913 23 578-596).-A criticism of the views put forward by Crato (A. 1913 ii 665). The author also gives an account of the interpretation which is afforded by the ionic theory of the behaviour of indicators in the volumetric estima- tion of acids and bases. H. M. D. Physico-chemical Volumetric Analyses. DoMINaA c. LANZA (Anal. Soc. Quina. AvgeFntinCt 1913 1 200-214).-The c3urse of neutralisation is followed by means of memurements of conduc- tivity. Figures are quoted for a mixture of hydrochloric and acetic acids sulphuric acid zinc chloride and morphine hydro- chloride. G. D. L. Pyro-analysis of Drugs. L. ROSENTHALER (Ber. Deut. Phacrm. Ges.1913 23 577. Compare A 1911 ii 948).-A piece of appar- atus for use in this method is described. The drug is placed a t the bottom of a tesbtube and covered with a layer of glass-wool; a tube slightly smaller in diameter than the test-tube is inserted in the latter the lower end of the tube resting on the layer of glass- wool whilst the upper end is connected with an exhaust pump. A piece of rubber tubing slipped over the tube f o m an air-tight joint between the mouth of the test-tube and the tube. The sublimate formed collects in the tube when the air is exhausted from the apparatus. w. P. s. o-Tolidine as a Reagent for the Colorimetric Estimation of Small Quantities of Free Chlorine. J. W. ELLMS and S. J. HAUSER (J. Ifid. Eng. Cham. 1913 5 914-917).-A hydrochloric acid solution of o-tolidine yields a yellow coloration with small quantities of free chlorine and the reaction may be used for the estimation of the latter in water which has been treated with the gas.The coloration develops in about three minutes is permanent for a t least thirty minutes and is not affected by the presence of the salts usually present in drinking waters. One hundred C.C. of the water are treated with 1 C.C. of a 0.1% o-tolidine solution in 10% hydrochloric acid and after five minutes the coloration obtained is compared with that produced by known quantities of chlorine under similar conditions. The coloration may be obtained in as small a quantity of chlorine as 0.005 part per million. w. P. s. Estimation of Chlorine i n the Blood.H. ROG~E and C . FRITBCH (Biochem. Zeitsch. 1913 58 175-176~.-Polemical. A reply to Bang’s criticisms of the authors’ method (A. 1913 ii 872). 8. B. 8.ANALYTICAL CHEMISTRY. ii. 67 Iodometric Estimation of Iodine Present as Iodide. ERICH MULLER and GUSTAV WEGELIN (Zeitsch. anuz. Chew. 1913 53 20-28).-When excess of potassium iodate is added to an acid solution of an iodide the iodine liberated conglomerates and is difficult to titrate. By the following device accurate results can be obtained. The solution to be tested is placed in a stoppered bottle 10 C.C. of 10% sulphuric acid are added and the liquid is covered with a layer of benzene. After adding excess of potassium iodate and thorough shaking a solution of 4 grams of anhydrous borax iu water is added and finally 3 grams of potassium iodide (not strictly necessary however).The iodine is now titrated by means of AT / 10-arsenious acid with constant ehaking. Thiosulphate should not be employed. L. DE I(. Estimation of the Sulphates in Wine by a Physico- chemical Volumetric Method. PAUL DUTOIT and MARCEL DUBOUX (BUZZ. SOC. chim 1913 [iv] 13 1068-1074).-A reply to Bruno and Turquand d’Auzay (compare Bull. SOC. chim. 1913 [iv] 13 24) in which the authors reaffirm the accuracy of their physicochemical volumetric method for estimating sulphates in wines by the; use of barium hydroxide (compare A. 1908 ii 781 892). W. G. Estimation of Total Sulphurous Acid in Wine. L. L ~ Y (Ann. FuZttiJ 19 13 6 595).-The method depends on the oxidation of sulphur dioxide by hydrogen peroxide.Fifty C.C. of the wine are mixed in a stoppered flask with 2 grams of barium peroxide; after eighteen hours’ contact hydrochloric acid is run in until bubbles of gas are no longer evolved ammonium chloride is added the mixture boiled and the barium sulphate collected ignited and weighed. The quantity of sulphate present in the wine is estimated in a separate portion of the sample and the difference between the two estimations is calculated into sulphur dioxide. W. P. 8. New Method for the Volumetric Estimation of Thiosulphate in the Presence of Sulphite. J. BODNAR (&itsoh. anal. Chm. 1913 53 37-41).-The process is based on the fact that thio- sulphates when treated with silver nitrate yield in the end silver sulphide and free sulphuric acid. After removing the excess of silver by means of sodium chloride the acidity can be determined by standard alkali.Sulphites do not interfere. L. DE K Detection and Estimation of Minute Traces of Selenious Acid. JULIUS MEYER and WILHELM VON GARN (Zeitsch. anal. Chem. 1913 53 29-33. Compare A 1913 ii 948).-1nto two cylinders are put 5 C.C. of the solution to be tested and 5 C.C. of a solution of selenious acid of approximately the same strength respectively ; 70 C.C. of water are added also a drop of gum arabic and 5 C.C. of 5-2ii. 68 ABSTRACTS OF CHEMICAL PAPERS. 5% hydrochloric acid and then the whole is diluted to 99 C.C. After adding to each tube 1 C.C. of potassium iodide solution and stirring vigorously the colo,rations which are due to iodine and to colloidal selenium are after five minutes compared in a Krum colorimeter.Addition of starch solutions may be useful. L. DE K. Comparison of the Kjeldahl-Gunning-Arnold Method with the Kjeldahl and Gunning Methods of Estimating Nitrogen. T. C. TRESCOT (J. Ind. Eng. Chem. 1913 5 914-915).--The Kjeldahl-Gunning-Arnold method was found to yield more trust- worthy resulta than the Kjeldahl or Gunning methods. W. P. s. Apparatus for Use in the Estimation of Nitrogen in Soils by Kjeldabl’s Method. ALBERT HUTIN (Ann. Chim. anal. 1913 18 426-428).-0wing to the small quantity of nitrogen present in soils a relatively large portion of the sample must be taken for the estimation and the insoluble substances (sand etc.) remain- ing after the digestion cause difficulties to arise in the subsequent distillation of the ammonia.It is therefore recommended that t8he acid digestion mixture should be transferred to a flask and steam-distilled after the addition of sodium hydroxide. The flask is closed with a rubber stopper through which pass the stem of a tapped funnel a tube for the introduction of superheated steam a delivery tube which is connected with a condenser and a tube reaching to the bottom of the flask; the outer end of the latter tube is connected with a pump so that the contents of the flask may be withdrawn a t the end of the distillation. w. P. s. Apparatus for Use in the Distillation of Ammonia in Kjeldahl’s Method. EMM. POZZI-ESCOT (Bull. Assoc. Chim. Sucr. Dist. 1913 31 235-236).-A description of a still-head is given ; it consists of an elongated bulb provided with a stem which passes through the stopper of the distillation flask.This stem extends upwards into the bulb itself and is then bent downwards in the form of a spiral. The vapours from the flask pass through the spiral then enter the bulb and leave the latter by a tube a t the top. Any alkaline spray escaping from the flask is effectually collected a t the lower part of the bulb and returns with other condensed liquid to the flask a narrow tube leading from the bottom of the bulb and passing down the centre of thO stem being provided for this purpose. w. P. s. Iodometric Estimation of Arsenic in Iron and in Iron Ores after Precipitation with Hypophosphorous Acid. L. BRANDT (Chern. Zeit. 1913 37 1445-1447 147 1-1472 1496 -14969.- Of ores 10 grams are mixed with 8 grains of potassium chlorate and 60 C.C.of strong hydrochloric acid and the whole is heated until all but some siliceous matter is dissolved. After diluting with water the filtrate is made up t o about 120 C.C. Of iron or steel samples 10 grams are dissolved in dilute nitric acid and thenANALYTICAL CHEMISTRY. ii. 69 evaporated to dryness with addition of sulphuric acid ; the residue is then dissolved in about 125 C.C. of dilute hydrochloric acid. In either case the solution is heated to boiling and the iron reduced by adding sodium hypophosphite which then also yields a deposit of metallic arsenic. For iron ores 20 grams and for iron or steels 40 grams will suffice. Towards the end another 35 C.C. of hydrochloric acid are also added.After washing the filter and contents are removed and treated with 15 C.C. (or less) of a solution containing 6 grams of potassium iodate and 30 grams of potassium iodide in 500 C.C. Owing to a trace of free iodine always present the arsenic dissolves slowly a t first more rapidly afterwards with liberation of iodine which must then be a t once titrated with tliiosulphate. I n the circumstances 1 atom of Method of Forming Realgar and its Influence on the Separation of Arsenic from Tin. H. CABON and D. RAQUET (An92. Chim. unal. 1913 18 432-434).-When a mixture of stannous sulphide and arsenic trisulpliide is boiled with hydrochloric acid the stannous sulphide is converted into stannous chloride whilst the arsenic trisulphidc is reduced to the disulphide and remains insoluble; the disulphide is also insoluble in ammonia. In the case of a precipitate containing tin antimony arsenic and gold sulphides it is recommended that the tin and antimony sulphides should be separated by boiling the mixture with hydrochloric acid; the insoluble portion is then oxidised with nitric acid when the arsenic is obtained in solution whilst the gold sulphide still remains insoluble.w. P. s. The Dehydration and Recovery of Silica in Analysis. F. A. GOOCH F. C. RECKERT and S. 8. KUZIRIAN (Amsr. J. Sci. 1913 [iv] 36 598-604).-After a large number of experiments the authors recommend drying the silica as recovered by evaporation on the steam-bath a t a temperature of l l O o before attempting to remove the soluble salts with dilute hydrochloric acid.Half an hour's ignition over a Bunsen burner is then sufficient to drive off the last traces of water. Should there be a further tendency to lose weight when heated over the blast this is not caused by water not yet expelled but by alkali compounds which should be removed by the usual treatment with sulphuric and Elementary Analysis of Substances containing Nitrogen. WALTER EICHHORN (Ch6WZ. Zd. 1913 37 1465).-Tf the copper spiral used in elementary analyses is reduced in a current of hydrogen and allowed to cool in that gas it retains sufficient hydrogen to affect seriously the analytical results. Allowing the spiral to cool in a stream of nitrogen does not improve matters much; it is necessary to heat strongly in nitrogen after the reduction with hydrogen is complete and then to allow to cool in nitrogen in order to obtain good results.The precipitate is collected on an asbestos filter. iocline=l atom of arsenic. L. DE K. hydrofluoric acids and allowed for. L. DE K. T. S. P.ii. 70 ABSTRACTS OF CHEMICAL PAPERS. Thioacetic Acid as a Reagent. NAZARIO ALVAREZ (Anal. SOC. Quim. Argentinu 19 13 1 122-1 28).-A solution of ammonium thioacetate is used as a source of hydrogen sulphide. The author claims that the nascent agent is more effective than the gas. I n applying it the thioacetate is added t o a solution of the metal salts in excess of hydrochloric acid. G. D. L. Thioacetic Acid,as a Reagent. Action on Salts of Rare Metals. NAZARIO ALVAREZ (Anal. SOC. Quim. Argentina 19 13 1 223-230).-Ammonium thioacetate in t,he presence of hydro- chloric acid may replace hydrogen sulphide in its action on vanadic molybdic tungstic selenious and telluric acids and on thallous sulphate palladium chloride ruthenium chlorate and sodium iridio-chloride.G. D. L. A Simple Process for Nitrating Sodium Hydroxide Solu- tions. ERNST ALTMANN (Chem. Zeit. 1913 37 1465).-The total alkali present hydroxide and carbonate is estimated by titrating the hot solution with standard sulphuric acid using phenol- phthalein as indicator. The amount of sodium hydroxide present is estimated by titration after precipitating the carbonate with barium chloride. T. S. P. Flame Reactions of the Alkali and Alkaline-earth Metals. LUDWIG KOPA (Chem. Zed. 1913 37 1506).-The author recommends a rod of graphite in place of the ordinary platinum wire for use in flame reactions (compare Kopa A.1913 ii 722; Wedekind A 1912 ii 382; 1913 ii 578). The graphite is most readily obtained from an ordinary lead pencil; i t does not break when quenched in cold water . T. S. P. Titration of Calcium and Magnesium in the Same Solution. PAUL J. Fox (J. Ind. Eng. Chem. 1913 5,910-913).-The solution containing the calcium and magnesium is treated while hot with oxalic acid and ammonia is added slowly until the solution is slightly alkaline in reaction. Ammonium arsenate is then added to the hot solution followed by ammonia until the ammonium magnesium amenate commences t o precipitate. After cooling an excess of ammonia is added and the precipitate is collected after fifteen hours and washed with dilute ammonia. The precipitate is now rinsed into a flask with water and dilute sulphuric acid; the acid solution is heated and titrated with standardised potassium permanganate solution.The mixture is then cooled 25 C.C. of diluted sulphuric acid (1 1) and 5 grams of potassium iodide are added and the solution is titrated with thiosulphate solution until the coloration is light yellow; i t is then placed in the dark for KONRAD SCHENK (Chern. Zeit. 1913 37 1464).-The bronze is dissolved in nitric acid and the tin estimated as dioxide the impurities in which are determined about five minutes and the titration completed. w. P. 8. The Rapid Analysis of Bronzes.ANALYTICAL CHEMISTRY. ii. 71 in the usual way by fusion with sodium carbonate and sulphur etc.Copper and lead are estimated in the filtrate by the usual electro- lytic rapid methods after which the iron and any aluminium are precipitated as hydroxides. The filtrate from the iron is evaporated to dryness after the addition of a few C.C. of sodium hydroxide in order t o re-move ammonium salts and the residue again evaporated with concentrated sulphuric acid to remove nitric acid. The residue is dissolved in water a large excess of sodium hydroxide added and the zinc estimated electrolytically using a rotating cathode. T. S. P. Microchemical Detection of Aluminium. F. RATHGEN (Zeitsch. anal. Che?n. 1913 53 33-37).-A particle of the alumina material is heated in a small platinum crucible with && C.C. of crystallised ammonium fluoride and 4-5 drops of strong sulphuric acid and the whole is very gradually evaporated to dryness and then heated for a moment to redness.When cold the mass is detached if necessary with the aid of a drop of water and then examined under the microscope. Aluminium is easily recognised by the colourless corundum-like hexagons which however may bO slightly coloured by iron or chromium. Four micro-illustrations are Estimation of Alumina in Bauxite. W. TRAUTMANN (Zeitsch. angew. Chem. 1913 26 702-703).-0*5 Gram of the finely powdered substance is fused in an open nickel crucikle with an excess of sodium peroxide and a little hydroxide. The fusion is dissolved in a little water diluted to about 500 c.c. and filtered into a litre flask. The undissolved mass is ignited and again fused with the soda mixture then dissolved in 20 C.C.of water and without filtering added t o the main solution. When cold the liquid is diluted up to the mark and after shaking portions of 100 C.C. are filtered off. The solution is supersaturated with hydrochloric acid and then boiled with a slight excess of ammonia. The precipitate after being washed once with water containing a little ammonia and ammonium nitrate is rinsed from the filter and redissolved in nitric acid and then again precipitated by ammonia using the same filter for collecting the alumina. After washing with the above liquid the precipitate is a t once heated in a platinum crucible until the ash is white. I n order to free it from traces of silica it is heated with 2 C.C. of hydrofluoric and 15 drops of sulphuric acid and after expelling the acids heated over the blow- pipe so as to render the alumina non-hygroscopic and to remove Use of Diphenylcarbohydraeide as Indicator in the Titration of Iron by the Dichromate Method.L. BRANDT (Zeitsch. anal. Chern. 191 3 53 1-20).-The solution of ferric chloride containing large excess of hydrochloric acid is reduced in the ordinary manner with stannous chloride the excess of which is then removed by mercuric chloride. After adding the usual solution of manganese sulphate containing free sulphuric acid and also phosphoric acid 5 C.G. of the above indicator are added and the liquid titrated with given. L. DE E. the last traces of sulphuric acid. L. DE K.ii. 72 ABSTRACTS OF CIIEMICAL PAPERS. standard potassium dichromate until the colour reddish-violet at first gradually passes into a pure green.The indicator is prepared by dissolving 0.1 gram of s-diphenyl- carbohydrazide in 35 C.C. of concentrated acetic acid and diluting up to 100 c.c.; the solution does not keep well rarely more than Colorimetric Estimation of Small Quantities of Manganese in Water. L. HARTWIG and H. SCHELLBACH (Zeitsch. N a b . Ganussm. 1913 26 439-442).-A method depending on the oxidation of the manganese by ammonium persulphate in the presence of silver nitrate is recommended as being more rapid than a similar method described by Schowalter (A. 1913 ii 880) and more trustworthy than that proposed by Haas (ibid. ii 437). Fifty c.c. or more of the water are treated with 0.5 C.C. of nitric acid evaporated to above one-half the original volume ; after cooling a quantity of silver nitrate more than sufficient to precipitate the chlorides is added followed by 10 C.C.of a 10% ammonium persulphate solution. The mixture is heated on a water-bath until the silver chloride has settled completely then heated t o boiling cooled and the coloration obtained compared with that exhibited by known quantities of permanganate diluted with a solution prepared by boiling for twenty minutes 2 litres of water after the addition of 40 grams of ammonium persulphate and 1 2 C.C. of a 1% silver nitrate solution. w. P. s. Estimation of Manganese Vanadium and Titanium in the Presence of One Another in Pig-iron and Steel. C. W. WRIGHT (Chew. News 1913. 108 248-249).-A quantity of 1-1 grams of the sample is dissolved in 35 C.C.of nitric acid D 1.2 the solution is filtered and the filtrate is heated after the addition of sodium bismuthate; sulphurous acid is then added the solution is cooled treated with an excess of sodium bismuthate and filtered the filter and residue being washed with 3% nitric acid. An excess of N/l0-ferrous sulphate solution is added to the filtrate followed by the addition of N/ZO-permanganate solution. As long as there is an excess of ferrous sulphate the permanganate solution introduced a t the rate of 2 or 3 drops per second is decolorised immediately but when the oxidation of the vanadium commences there is a dis- tinct retardation in the disappearance of the pink coloration. The reading is now taken and the titration is continued until a permanent pink colour is obtained; in case of doubt the operation may be repeated any number of times by again adding ferrous sulphate and titrating with permanganate solution.The quantities of manganese and vanadium present are then found by calculation. The solution is now transferred to a graduated cylinder hydrogen peroxide is added and the coloration obtained is compared with a standard prepared by similarly treating pig-iron or steel free from titanium or vanadium and adding to the solution a quantity of vanadium exactly equal to that found in the sample hydrogen peroxide and a definite volume of a standard titanium solution. a week. L. DE K. w. P. s.ANALYTICAL CHEMISTRY. ii. 73 The Estimation of Chromium as Chromic Oxide.G. ROTHAUG (Zettsch. anwg. Chem. 1913 84 165-189).-Precipitation of chromic salts with ammonia and ignition of the precipitate yield high results. The precipitate must be ignited a t first in a closed crucible as it becomes incandescent with violent projection of particles a t 420-680° a,ccording to the coarseness of the material. The average excess of weight found starting with pure chromic sulphate solution is 0.75% Cr. Ammonium sulphide gives a mean excess of 1*60% and potassium iodide and iodate + 1.02% Cr. The results are the same whether hard glass or platinum vessels are used. The error is lessened by shortening the preliminary heating to thirty seconds and then transferring to an electric furnace but chromic acid is always formed to a small extent.Washing the precipit’ate extracts chromic acid and repeated ignition followed by washing yields f urtlier quantities of chromic acid. Alkalis and lime are shown to be absent and the solutioii contains a chromic chromate. The formation of this compound is a maximum a t 300° and is observable even at looo. The quantity produced falls rapidly to 400° and very gradually after that point. The reaction is 5Cr,03+ 9 0 ~ C I - ~ ( C ~ O ~ ) ~ and it is probable that solid solutions are formed. The chromic acid in the washings may be estimated by Moulin’s colorimetric method with diphenylcarbazide (A. 1904 ii 368) whilst the same method applied after oxidation with hydrogen peroxide gives the total chromium. The composition of the chromic chromate Cr2(Cr0& has been determined in this way.Ignition of the hydroxide in hydrogen gives completely accurate results. C. H. D. Sensitive Reaction of Molybdenum and Tungsten in Presence of Mercury. Em. POZZI-ESCOT (Bull. SOC. chim. 1913 [iv] 13 1042).-In the author’s previous note on this subject (A. 1913 ii 532) the words tungstate and molybdate should be interchanged whenever they occur. T. A. H. Eetimation of Titanium by Titration. EDMUND KNECHT (Zeitsch. ungew. Chern. 1913 26 734-735).-A claim for priority over Neumann and Murphy (A 1913 ii 1079); compare Knecht (A* 1907 ii 654) and Hibbert (A. 1909 ii 351). Apparatus for the Melting Points of Substances of Indefinite Melting Point. A. P. BJERREGAARD (J. I d . Eng. Chcm. 1913 5 938-940).-The apparatus consists of a block of iron having one face inclined a t an angle of 45O to the horizontal.A number of grooves 0.5 in. wide and 0.25 in. in depth are provided down this face and samples of the material to be tested are pressed into the upper part of the grooves; two step-like cuts are made across the tops of the ridges between the grooves the material filling the upper step. Heat is applied to the bottom of the block and is so regulated that the temperature of the block as determined by a thermometer inserted in a mercury cup a t the top is raised T. S. P.ii. 7’4 ABSTRACTS OF CHEMTCAL PAPEHS. 100 in about every 100 seconds. The inclined face is covered with a glass plate. The temperature a t which the material is liquid enough to flow from the upper t o the lower step-like cut is taken as the melting point.The apparatus may be used for such sub- An Anomalous Reaction of Resorcinol. EDWIN P. HICKS (J. Amer. Chew. Soc. 1913 35 1891-1893).-From the author’s experiments it appears that the commonly accepted idea that resorcinol can be titrated as a dibasic acid with alkali hydroxides using Poirrier’s blue as an indicator is erroneous. If an aqueous solution of resorcinol is titrated with a standard solution of alkali hydroxide neutrality to the indicator is attained when a 1-14 molecular proportion of the alkali has been added; after keeping for ten to fifteen minutes the alkali in the neutralised solution can be titrated back with a mineral acid the liberated resorcinol being without effect on the indicator. Even when resorcinol is kept in 0.1 molar solution for three hours with a decimolecular proportion of alkali hydroxide the solution is found to be alkaline to the indicator and the whole of the alkali can be titrated before acidity is restored. The author inclines to the view that alkali induces in resorcinol a change t o some non-phenolic and possibly tautorneric substance ; extraction of the solutions with ether yielded nothing but ordinary resorcinol.cH<Co-CH;>CO CH*CH stances as pitch asphaltum etc. w. P. s. It is suggested that the ketonic formula possibly represents the less acidic substance. Modiffcation of the Fehliag-Soxhlet Volumetric Method. OTTORINO CARLETTI (Boll. chim. farm. 1913 52 747-748).-The end-point in the titration of reducing sugars by this method may be accurately determined by taking advantage of the fact that cuprous potassium cyanide does not react with phenolphthalin whilst cupric potassium cyanide gives with it a red coloration.The phenolphthalin reagent is made by mixing phenolphthalein (1 gram) potassium hydroxide (10 grams) zinc dust (5 grams) and water (100 c.c.) and boiling until decolorised. In the titration the sugar solution is run into Fehling solution and when reduction is almost complete a drop of the liquid is withdrawn mixed with a drop of the phenolphthalin reagent and the mixture treated with two or three drops of potassium cyanide (10%). When the end of the titration is reached this test will show no coloration whilst as long as cupric salt is present a red coloration will be obtained. D. F. T. R. V. S.Influence of the Metals Present in Urine on the Velocity of the Reducing Tests for Dextrose. GERTRUD WOKER and ELTSABETH BELENCKI (Pfliiger’s Archiv 191 3 155 45-67).-The presence of mercury in urine retards the Nylander test for dextrose and affects also other tests. Serum preparations containing mercury behave very irregularly. The indication of dextrose in urine by the usual reduction methods is affected also by the presence ofANALYTICAL CHEMISTRY. ii. 75 arsenic iron potassium iodide and salicylic acid. The effect on the different methods is not quantitatively the same. Urine is considered to contain two substances the one accelerating the inter- action of dextrose with methyleneblue bismuth nitrate or mercuric chloride the other retarding the reaction with alkaline copper sulphate or silver nitrate.The velocity of reduction of dextrose is in either case a function of the urine concentration. E. F. A. Velocity of Reduction of Methylene-blue by Dextrose and Laevulose and its Application to Urine Analysis. ,J. F. MUSTEX and GERTRUD WOKER (Pfliiger's Archiv 1913 155 92-96).-1n presence of alkali hydroxides methylene-blue is much more rapidly reduced by lzvulose than by dextrose and a met'hod is based on this difference for detecting and discriminating between these two sugars in urine. E. F. A. Gabriel Bertrand's Method of' Sugar Estimation. M. ROSE- BLATT (Biochem. Zeitsch. 1913 57 335-336).-A reply to Sonntag (A. 1913 ii 800). The Micro-method of Sugar Estimation. IVAR BANG (Riochem. Zeitsch. 1913 57 300-312).-The author has introduced certairi modifications into the method previously described by him (A.1913 ii 446). He employs 1 C.C. of the copper solution instead of 3 c.c. and he has reduced the amount of acid used in the coagulation of the protein which can be effectively done by substi- tuting hydrochloric f o r acetic acid. The solution now employed for coagulating the blood is made up of the following mixture 1360 C.C. saturated potassium chloride solution + 640 C.C. water + 1.5 C.C. 25% hydrochloric acid. N/200-Iodine solution can now be used for titration and this is made from 5 C.C. N/l0-hydrochloric acid + 1-2 C.C. 20A potassium iodate solution + 2 grams potassium iodide+water up to 100 C.C. I n summer this solution should be titrated every twenty-four hours.An improved pincette for holding the flask during the reduction process is also described. Titration with the iodine solution is carried out until the blue starch colour remains permanent for thirty to sixty seconds. Various other new details are given b y t h e author. I n the micro-method the results of blood sugar analyses are usually slightly higher than those obtained by the macro-method. This can be accounted for by the fact that the solution containing the sugar decolorism a small amount of iodine before reduction by the copper solution. This amount is nearly constant. A subtraction of 0.015% from the total gives the correct result. Detection of Sucrose in Urine. ADOLF JOLLES (Biochem. Zeitsch. 1913 57 420422).-The author has previously shown that dextrose solutions on treatment with alkali are rendered optically inactive.The estimation of the change in the polarisation after such treatment will give a measure of the amount of dextrose present. Change of polarisation produced by inversion will give S. B. S. S. B. S.ii. 76 ABSTRACTS OF CHEMICAL PAPERS. the measure of the sucrose present. By employing both methods of treatment sucrose can be detected with certainty in the presence of dextrose. S. B. S. HANNS STIEGLER (J. Landw. 1913 6 1,399-426).-The amount of substance employed varies from 1.5 to 3 grams according to the amount of fibre present. The finely-powdered substance is added to 20 C.C. of water in a 300 Soxhlet milk-sterilising bottle treated with 60 C.C. of hydro- chloric acid (D 1-19> well shaken and left for ten minutes.Boiling water (to 200 c.c.) is then added and the flask immersed in boiling water for an hour a slow cdrrent of air being drawn through it all the time. When the heating is completed the residue is allowed to settle and the acid liquid drawn off through a tube closed with a plug of glass-wool. The latter is then removed from the tube and placed in the bottle containing the residue. This is next neutralised treated with 50 C.C. of potassium hydroxide solution (5%) and boiling water (to 200 C.C. as before) and again heated for half an hour in a water-bath. The hot solution is filtered through a porce- lain Gooch crucible with a disc of ignited asbestos paper covered with ignited and washed asbestos. The fibre and the glass-wool are washed successively with hot water (500 c.c.) and alcohol and then left in contact with ether for about half an hour.After filtering off the ether the crucible is heated for two hours at 100-105° weighed ignited and again weighed. Titrimetric Estimation of Potassium Xanthate. BROR HOLMBERG (Be?.. 191 3 46 3853-3859).-The estimation depends on the fact tohat free xanthic acid rapidly decomposes in solution into carbon disulphide and alcohol. The xanthate solution is treated with an excess of standard hydrochloric acid the mixture allowed to remain about ten minutes until the decomposition of the xanthic acid is complete and the excess of free mineral acid titrated with alkali. A volumetric method for the estimation of mercury depending on the formation of an insoluble mercuric xanthate is also described; the solution of the mercury salt (which must be present in the mercuric condition) is treated with potassium xanthate and the excess of the latter determined in the manner just described.The estimation can be carried out in the presence of chlorides bromides and sulphates but if iodides are present the mercuric xanthate must be filtered off before the excess of potassium xanthate is determined. It is claimed that mercury can be estimated in this manner more rapidly and more conveniently than by any other method. The author confirms the observations of previous workers that aqueous solutions of potassium xanthate are not very stable but finds that the sclid salt can be kept in a dry atmosphere without undergoing change. F.B. Estimation of Lactic Acid in Wine. THEODOR ROETTGEN (Zeitsch. Nahr. Gcnusem. 1913 26 437-439. Compare A. 1911 ii 942 ; 1912 ii 1005).-Results of experiments on the estimation New Method for Estimating Crude Fibre. N. H. J. M.ANALYTICAL CHEMISTRY. ii. ’77 of lactic acid i n wine and in the dry residue of the same show that the dry residue (total solids) of wine contains the whole of the lactic acid and is practically free from volatile acids. Compara- tive estimatio,ns of lactic acid by the methods described by Kunz and Moslinger showed that the processes are equally trustworthy. w. P. s. Estimation of Hydroxybutyric Acid. PHILIP A. SHAFFER and W. MCKIM MARRIOTT (J. Biol. Chem. 1913 16 265-280).-The method of estimating hydroxybutyric acid by oxidising it to acetone with chromic acid gives uniformly about 90% of the theo- retical values; the values must therefore be corrected by an addition of 1076 of the amount formed.The results obtained by the oxidation method were compared with those obtained by Black’s ether extraction method. A procedure for the isolation and purification of hydroxybutyric acid in the form of calcium zinc hydroxybutyrate CaZn(C,H,03)4 m. p. 200° (decornp.) is described. W. D. H. ErJtimation of P-Hydroxybutyric Acid in Blood and Tissues. W. MCKIM UARRIOTT ( J . Biol. Chem. 1913 16,293-298).-Shaffer’s method is applicable to blood and tissues provided proteins are removed (by sodium acetate) ; paired glycuronic acids dextrose and protein remnants are then precipitated by basic lead acetate and ammonia.Full details of distillation etc. both for large and small quantities of blood are given. By applying the nephelometer f o r the ec;timation of acetone occurring as such or as acetoacetic acid or to that obtained by oxidation of 8-hydroxybutyric acid it is possible to make a complete analysis with only 2-5 C.C. of blood. W. D. H. General Method for the Estimation of Fixed Acids in Vegetable Substanoes. EMM. POZZI-ESCOT (BUZZ Assoc. CAim. Sucr. Dist. 1913 31 225-230).-Oxalic tartaric lactic citric malic and succiuic acids may be estimated in the presence of each other by means of the following method which is a combination of processes described previously by the author (compare A. 1908 ii 740 904 993 1078). Oxalic A cid.-The solution containing the mixed acids is neutralised with ammonia ammonium chloride and acetic acid are added and the oxalic acid is precipitated as calcium oxalate or as barium oxalate; the oxalate is separated dissolved re-precipitated and then titrated with permanganab solution in the usual way.The filtrates from the oxalate precipitate are mixed treated with sulphuric acid t o remove calcium or barium salts and then diluted t o a definite volume. The solution is used for the estimation of the other acids. Tartaric Acid-This acid is precipitated from a portion of the solution as magnesium tartrate aft.er the addition of 50% of alcohol to the solution; the precipitate is collected washed with alcohol ignited and the tartaric acid calculated from the weight of magnesia obtained. Lmtic Acid.- Another portion of the solution is treated with a large excess ofii.78 ABSTRACTS OF CHEMICAL PAPERS. an alcoholic barium bromide solution and alcohol when all the acids are precipitated with the exception of lactic acid. After filtration the solution may be evaporated acidified with sulphuric acid and titrated first to neutrality to Congo-red and then to phenolphthalein the latter titration giving the quantity of lactic acid. Or,_the solution is evaporated to dryness the residue calcined and the resulting barium carbonate titrated. Citric A cid-The barium precipitate obtained in the separation of the lactic acid is freed from barium by means of sulphuric acid and then treated with an excem of lead acetate in acetic acid solution when lead citrate and tartrate together with lead sulphate are precipitated whilst lead malate and succinate remain in solution.After the lead has been removed from the precipitate as sulphide the citric and tartaric acids are precipitated as their barium salts the latter being collected ignited and the barium carbonate titrated. The quantity of tartaric acid found previouslg is deducted from the result to give the citric acid. Malic and Succinic Acids.-The solution containing the lead salts of these acids is treated with hydrogen sulphide the lead sulphide is separated and in one-half of the solution the two acids are estimated together by double titra- tion whilst the succinic acid is estimated in the other half of the solution by precipitation as its barium salt after the malic acid has been oxidised with permanganate (compare A.1908 ii 993). w. P. s. Reaction of Nopic Acid (Reaction Characteristic of Oxalic Acid). BERNABB DORRONSORO and OBDULIO FERNANDEZ (Anal. Pis. Quim. 1913 11 441-443).-The coloration with resorcinol and sulphuric acid supposed by Fernsndez to be caused by nopic acid derived by oxidation of the terpenes by means of alkaline permanganate (A. 1910 ii 1119) is shown to be due to oxalic acid the sodium salt obtained in the oxidation being that of oxalic and not of nopic acid. G. D. L. Modification of Jonescu’s Test for the Detection of Benzoic Acid. P. FLEURY (J. Pharm. Chim. 1913 [vii] 8 460-461).- This test which depends on the conversion of benzoic acid into salicylic acid by the action of hydrogen peroxide is very sensitive when carried out in the following way To 10 C.C.of an aqueous benzoic acid solution are added successively three drops each of dilute ferric chloride solution dilute hydrogen peroxide soIution and 3% ferrous sulphate solution. A violet coloration commences to appear in about thirty seconds and reaches its maximum in about ten minutes; a distinct coloration is obtained with 0.2 mg. of benzoic acid. The mixture should not be heated as the oxida- tion of the benzoic acid then proceeds too far and the character- istic violet coloration is not obtained. w. P. s. Detection of Vegetable Fats in Animal Fats. If. KLOSTER- MANN (zeilsch. A?ah. Genussrn. 1913 26 433-437).-A method of isolating cholesterol and phytosterol by means of digitonin (com-ANALYTICAL CHEMISTRY.ii. 79 pare A 1913 ii 885) is described. One hundred grams of the fat are saponified with alcoholic potassium hydroxide solution and after dilution the fatty acids are separated by the addition of hydrochloric acid; 250 C.C. of ether are then added the ethereal solution of the fatty acids is separated from the aqueous portion and washed three times with water. The ethereal solution is mixed with 250 C.C. of light petroleum and 25 grams of sodium chloride shaken filtered and the filtrate is treated with 1 gram of digitonin dissolved in 20 C.C. of alcohol. After thirty minutes the crystals which separate are collected washed with ether dried and boiled with acetic anhydride until completely dissolved. The excess of acetic anhydride is evaporated the residue dissolved in 50 C.C. of alcohol and 25 C.C.of water are added slowly to the solution. The crystalline precipitate is collected washed with 70% alcohol dis- solved in ether the solution is evaporated to dryness and the residue is crystallised twice from alcohol the M. p. being then determined. Pure lard yields crystals m. p. l l O o whilst in the case of lard containing 2.5% of rape oil the crystals have m. p. 1 1 8 O . Butter gives crystals having m. p. 113O which is raised fo 115O when the butter contains 2.5% of cocoanut oil. The crystals obtained from pure rape oil or cocoanut oil have m. p. 126-128O. w. P. s. Estimation of Acetone. W. MCKIM MARRIOTT (J. Biol. Chem. 1913 16 281-288).-The Messinger method (A. 1889 90) gives correct results. The Scott-Wilson method gives accurate results only when certain modifications of the original procedure are made; it is applicable to very minute quantities of acetone.In distilling a very dilute acetone solution all the acetone may be collected in the distillate within ten minutes W. D. H. Nephelometric Estimation of Minute Amounts of Acetone. W MCKIM MARRIOTT (J. Biol. Chem. 1913 16 289-292).-When the quantity of acetone is too small for estimation by the Scott- Wilson method as for example in small amounts of blood the estimation may be accurately made nephelometrically ; the opales- cence observed is produced by adding the acetone to a silver- mercury cyanide solution K. PECHE (Ber. Deut. Bot. Ges. 1913 31 45S-462).-When sections of the rind of white or better black radish are placed in a solution of potassium myronate (10% or less) saturated with barium chloride white globules presumably of barium sulphate are deposited on some of the protein cells; with strontium chloride the precipitate is granular whilst with calcium chloride well-formed needles of calcium sulphate are formed after some time both in and outside the sections.The sulphates are produced by the joint action of the glucoside and the alkaline earth. On the assumption that the ally1 group of the mustard oil is the only substance present which reacts with osmic acid (tannins have not been detected and the presence of fats and oils in the rind of W. D. H. Microchemical Detection of Myrosin.ii. 80 ABSTRACTS OF CHEMICAL PAPERS. radish is improbable) the glucoside may be localised by slightly heating a washed ssction in 1% osmic acid.11. Estimation of Amino-nitrogen in t h e Tissues. DONALD D. VAN SLYKE ( J . Biol. Chern. 1913 16 187-196).-The amino-acids are extracted from the tissues with hot water. Uncoagulated proteins are precipitated by alcohol ; alcohol and ammonia (present in the extract) are removed by concentration in a vacuum and the amino-nitrogen estimated by nitrous acid. The action is rapid and is only slightly increased after hydrolysis with hydrochloric acid; this indicates that the bulk of the amino-acids are free. N. H. J. M. The Fate of Protein Digestion Producte in the Body. W. D. H. Estimation of Amino-acid-Nitrogen in Urine. 8. R. RENEDICT and J. R. MURLIN (J. Biol. Chm. 1913 16 385-388).-The method previously published by the authors f o r modifying the form- aldehyde titration gives low results and it was found that certain amino-acids are in part removed by the preliminary treatment with lead.The procedure now recommended consists in adding phosphotungstic acid to dilute urine; three hours later the clear fluid is poured off and phenolphthalein and barium hydroxide added until it turns pink; after an hour it is filtered and the filtrate neutralised ; it is then titrated with neutral formaldehyde to a deep red colour. The result is corrected by deducting the amount of *V/ 10-sodium hydroxide necessary to produce the same colour in an equal quantity of water free from carbon dioxide with the same mount of formaldehyde. OTTO MAYEB (Zeitsch. angcw,. Chem. 1913 26 639-640; Pharm. Zerztr.-h. 1913 54 1205-1208).-The author recommends that in the examination of urines for albumin the following reactions should be carried out in the cold; (a) a mucin test ( b ) a protein test with a slight modification of Jolles's reagent. For quick approximate estimations 5-10 C.C. of urine are floated in a conical glas? on the same volume of a reagent made by dissolving 5 grams of mercuric chloride 5 grams of citric acid and 40 grams of salt in 500 C.C. of water. At the end of 1.5 minutes a well-defined white ring appears a t the junction of the liquids when 0.001% of albumin is present. Stronger urines are diluted after preliminary tests until the same time is required for the development of the ring. Estimation of Protein in Urine by the Centrifugal Method. CASIMTR STRZYZO~VSRI (Zeitsch. physiol. Chenz. 1913 88 25-3'7).- I n estimating the amount of protein in urine after adding Esbach's reagent and centrifugalising the depth of the precipitate varies with the temperature and with the specific gravity of the urine. The method may be made exact by the use of a standard centrifuge standard sedimenting tubes a constant temperature and by bring- ing up the specific gravity of the urine to a standard level (D 1.030); this is best done by the addition of zinc sulphate. W. D. H. A Delicate Test for Albumin in Urine. J. C. W. W. D. H.