THE ANALYST. 161 ORGANIC ANALYSIS. Determination of Formaldehyde. C. Kleber. (Pluzrm. Rev., xxii., 94 ; through Pharm. Joiirn., 1904, lxxii., 428.)-To a concentrated solution of commercial sodium hydrogen sulphite, which generally contains a considerable quantity of free sulphurous acid, a solution of pure sodium hydroxide is added, until the odour of sulphurous acid ha8 completely disappeared. A slight excess of sodium hydroxide does not matter. The solution is then diluted with water until 30 C.C. of it exactly neutralize 50 C.C. of Towards this solution formaldehyde behaves like an alkali, and can be titrated accordingly. cv. P. s. sodium hydroxide, using phenolphthalein as indicator. The so-called “ Hydrocellulose.” Arthur Landauer Stern. (Joitrn. Chent. Soc.)-When cellulose is exposed to the action of dilute acids under certain conditions, the powder of so-called hydrocellulose” obtained is shown to have the same elementary composition as cellulose itself, and not to correspond to the formulaTHE ANALYST.C,, H,, 0,, usually assigned to it. A small amount of soluble matter, probably con- sisting partly of &glucose, is also formed at the same time. A. G. L. Dry Defecation in Optical Sugar Analysis. W. D. Horne. (Jounz. Amer. Cliem. SOC., xxvi., 186.)-The error in the polariscope readings due to tbe volume of the precipitate obtained by adding lead subacetate solution, and then diluting the liquid to 100 c.c., can be largely eliminated by adding solid lead subacetate to the sugar solution after it has been made up to 100 C.C.This procedure leaves the volume of liquid in which the sugar is dissolved practically unchanged, and avoids the troublesome corrections of the older method, the results obtained directly agreeing well with the corrected results of the wet method. With some refinery solutions the grains of lead subacetate tend to become coated with insoluble crusts, which prevent their solution ; this difficulty is readily overcome by adding coarse, dry sand with the lead salt before shaking. A. G. L. Determination of Starch by Hydrolysis with Hydrochloric Acid. A. Rossing. (Zeit. ofentl. Chem., 1904, x., 61-64.)--Two methods were tried, the first being the one originally described by Sachsse, and the second a modification of the same. According to the first method, 3 grammes of starch or meal were formed into a paste with 200 C.C.of water, 15 C.C. of hydrochloric acid of specific gravity 1.125 were added, and the mixture heated on a water-bath for two and a half hours. After cooling, the solution was nearly neutralized, made up to 500 c.c., and the dextrose determined in 25 C.C. by Allihn’s method. I n the modified process, 2 granimes of meal were made into a paste with 100 ac. of water, 15 C.C. of concentrated hydrochloric acid (specific gravity 1-19> were added, and the whole heated in boiling water under a reflux condenser for two hours. The solution was then cooled, neutralized, diluted to 250 c.c., filtered if necessary, and the dextrose determined in 25 C.C. as before. The starches used in the experiments were wheat, potato, rice, arrowroot, and maize.To obtain the correct amount of starch known to be present, it was necessary to use the factor 0.94, instead of 0.9, to convert the dextrose found in the first method into starch, and 0.93 in the second method. Neither method is suitable for determining starch and dextrin in baked foods, such as bread, etc. w. P. s. Tbe Hydrolysis of Maltose and of Dextrin by Dilute Acids and the Determination of Starch. William A. Noyes, Gilbert Crawford, Charles H. Juniper, Edgar L. Flory, and Robert B. Arnold. (Joum. Aiuer. C h i n . SOC., xxvi., 266.)-From the results of their investigation, the authors conclude that the hydrolysis of maltose and of dextrin does not proceed strictly in accord with the law of mass action, a retardation setting in after a time.Whilst dextrose itself is scarcely affected in its reducing power by heating with a 2.5 per cent. solution of hydrochloricTHE ANALYST. 163 acid, they find that with maltose a maximum reducing power is reached after one hour's heating at 100" C., or twenty to thirty minutes' at 111' C. This maximum reducing power corresponds to a hydrolysis of 96 to 98 per cent. With the products obtained by the action of extract of malt on starch a maximum reducing power is obtained at the end of one hour, amounting to 96.4 per cent. for a 0.5 per cent. solution of starch, and 97.1 per cent. for a 2 per cent. solution. By the direct treat- ment of starch with 2.5 per cent. hydrochloric acid (specific gravity 1.125) in a 0.5 per cent. solution, a, hydrolysis of 97 per cent.is obtained in one hour, and of 98 per cent. in four hours. For the determination of starch, the authors recommend that, after filtration, 10 per cent. by volume of hydrochloric acid (specific gravity 1-125) should be added to the solution obtained by the action of malt extract on the material. The whole is heated for one hour in a boiling water-bath, making allowance for the time necessary for the solution to attain the temperature of the batb, and, after cooling, enough sodium hydroxide is added to neutralize 90 per cent. of the acid present. The liquid is then rnade up to a definite volume, filtered if necessary, and the reducing power determined by Fehling's solution; 100 parts dextrose found represent 93 parts of starch in the original material.The authors emphasize that each chemist should determine for himself, with pure dextrose, the ratio between dextrose and copper oxide given by the method he uses. Their own determinations are not very con- cordant, differing amongst themselves by about 10 per cent. A. G. L. Rapid Estimation of Starch in Barley and Malt. H. T. Brown and Millar. (Trans. Gtiiniiess Kesearch Lub., I., 1903, 79-91 ; through Brewing Trade liev., 1904, xviii., 101.)-The ground grain is extracted with alcohol, then treated with malt extract, and the starch calculated from the cupric reducing power of the solution. Five grammes of the very fine flour are extracted in a modified Soxhlet apparatus with alcohol, of specific gravity 0,920, to remove all reducing substances and alcohol- soluble nitrogen compounds.Three hours' extraction is necessary in the case of barley and nine hours' for malt. To prevent frothing a little solid paraffin may be added to the extraction flask. The extracted flour is well boiled with 100 C.C. of water, cooled to 57" C., 10 C.C. of active malt extract are added, and the conversion allowed to proceed for 1 hour. The solution is then boiled, filtered into a 200 C.C. flask, the residue well washed, and the volume made up after cooling. The cupric reducing power of 20 C.C. of this solution is now determined, and the maltose calculated from the reduced copper after correction for reduction due to the malt extract (see Trans. Chem SOC., 1897, 94); 84.4 parts of maltose correspond to 100 parts of starch. A malt showing a diastatic power of 80 Lintner should be employed for making the cold malt extract.The moisture is also determined in the flour so that the results may be calculated on the dry material. w. P. s. The Detection of &naphthol in Benzonaphtbol. A. Jorissen. ( A ? m de Chint. m2nl., 1904, ix., 86, 97.)-According to the author, benzonaphthol as sold is164 THE ANALYST. not infrequently contaminated with P-naphthol. The test prescribed by the French Codex is to introduce a fragment of potassium hydroxide into a chloroform solution of the thoroughly dried drug, and to boil the liquid, which ought not to turn blue. I n the author's opinion the results of this test are sometimes doubtful. Another Codex test consists of mixing an alcoholic solution with an equal volume of nitric acid, and adding a few drops of a, solution of acid mercuric nitrate, which ought not to produce a cherry-red coloration. The following test is recommended as capable of detecting 1 per cent.of P-naphthol : 0.02 grsmme of the drug is shaken with 2 C.C. of glacial acetic acid, and 1 or 2 drops of nitric acid (63 per cent.) introduced. In the case of pure benzo- naphthol the liquid remains colourless, whilst a bright yellow colour is given by P-naphthol or a mixture containing 1 per cent. of that substance. C. A. M. Analysis of a Sample of Bear-Grease. P. N. Raikow. (Client. Zed., xxviii., 272.)-The following table represents the values obtained in the analysis of fat from a bear killed in the neighbourhood of Sofia. The chief food of the animal had probably been hazel-nuts ; when killed, it appeared to have been asleep for more than one month : Belly.Kidneye. I I ... ... ... ... ... 2 5 O 15' Specific gravity ,? ... ... ... ... ... 15" 15' _- Melting-point of insoluble acids ... ... ... ... Acid value ... ... ... ... ... ... ... Ester value ... ... ... ... ... ... ... Iodine value ... Reichert-Meissl value ... ... ... ... ... Refractometer value i ... ... ... ... ... ... ... ... ... ... ? ? $ 1 ... ... ... ... ... 0.9104 0.9209 32-32 1" 2.2 192.6 98.5 61.2 at 25" 61.2 ,, 1-66 - 0.9211 ' 198.1-198.3 I 1.15 I 53.0 at 40° : 53.0 ,, 107 -4- 106 '5 In appearance the fat resembles lard. I t is pure white in colour, not quite solid even at'Oo C., and only slightly soluble in alcohol. A. G. L. Determination of Betaine by means of a Solution of Iodine in Potassium Iodide.V. Stanek. (li'ozprcicy Eeskk akad., 1904, 12, 36 ; through C'ltenL. Zeit. Rep., 1904, xxviii., 79.)-An aqueous solution of a betaine salt is precipitated by a solution of iodine in potassium iodide. The free base gives no precipitate with this reagent, but does so 8s soon as the solution is acidified. The precipitate is at first brownish-red in colour, but Boon changes to greenish crystals, which melt at 58-61" C. with liberation of iodine. They are practically insoluble in cold water. The author employs a solution of 100 grammes of potassium iodide and 153 gramrnes of iodine in 200 C.C.THE ANALYST. 165 of water. Sodium chloride and sulphuric acid both decrease the solubility of the betaine periodide, but an excess of the reagent is prejudicial.The experiments described in the origind paper show that betaine can be separated from glycocol, asparagine, tyrosine, glutamic acid, and ammonium salt8 by the above method. Acetic acid and lactic acid have no action on the precipitate, but the presence of urea, peptones, and purin bases appears to be unfavourable. w. P. s. The Hydrolysis and Synthesis of Fats by Platinum Black. H. Neilson. ('4iner. Journ. Phpsiol., x., 191-200.)-The author's experiments have proved that platinum black is capable of effecting the hydrolysis of ethyl butyrate in a similar manner to lipase. Thus, when 5 C.C. of a mixture of 200 C.C. of water, 10.4 C.C. of ethyl butyrate, and 2 C.C. of 1 per cent. thymol (as antiseptic) were mixed with 300 rnilligrammes of purified platinum black and kept at 38" to 40" C.with occasional shaking, the following amounts of hydrolysis, as measured by the free acid, were found : After 24 hours, 10.3 ; 48 hours, 28.3 ; '72 hours, 37.3 ; 96 hours, 49.0; and 144 hours, 68.0 per cent. The amount of hydrolysis increased with the proportion of plntinurn added, but not in direct ratio; on the other hand, the catalytic action was found to be independent of the concentration of the ethyl butyrate. The o p t i i t ~ w ~ ~ temperature for the action of the platinum black was about 50" C. The action of most substances poisonous to lipase was to restrict the influence of platinum to a similar extent. Sodium fluoride, however, which is very destructive to lipase, had a much less pronounced action on platinum black.On the other hand, hydrocyanic acid, which was very injurious to the action of platinum black, has much less effect upon lipase. The author also proved that platinum black was capable of effecting the synthesis of butyric acid and alcohol, but the synthesis was less pronounced than the hydrolysis. I n this respect platinum black also resembles lipase (ANALYST, xxvi., 106). C. A. RZ. Notes on Adamkiewicz's Albuminoid Reaction. Dupouy. ( B / i l Z . SOC. P ~ L o ~ I ~ L . Bordeaux. Ann. dc Chi?,&. (inal., 1904, ix., 107, 108.)-The author has found that the most suitable conditions for this reaction are by adding a mixture of 2 parts of glacial acetic acid with 1 part of sulphuric acid to the albuminoid substance, the violet coloration with green fluorescence being then regularly obtained.A similar coloration is given by a reagent consisting of 1 C.C. of sulphuric acid, 2 C.C. of glacial acetic acid, and 1 drop of formalin. This coloured liquid, however, examined spectroscopically, shows a large band between the red and blue parts of the spectrum, whereas the solution in Adamkiewicz's reaction has a spectrum resembling that of urobilin, with an absorption band between the b and F lines. c. A. M. The Determination of Sulphur in Caoutchouc. W. Each. (Chew. Zci!., xxviii., 200.)-The author recommends the method of Henriques as being very exact, provided suitable precautions are taken to guard against mechanical loss. Carius's166 THE ANALYST. method is not generally applicable, as it fails to bring inorganic sulphur present as barium sulphate, etc., into solution. Pfeiffer’s applioation of Eschka’s method (Chem. Zeit., xxviii., 38) gives good results if the mixture is heated to fusion after the carbon has been completely burnt. In many cases the rapid sodium peroxide method of V. Konck (Zeds. angew. Chem., xvi., 516), which can be carried out in a copper crucible, also gives satisfactory results. A. G. L. Contribution to the Study of Cigarette aad Pipe Smoke. J. Habermann.- (Zeits. physiol. Chew, 1903, XI., 148 ; through Chem. Zeit. Rep., xxviii., 25.)-The author finds that the quantity of nitrogenous bases in cigarette smoke is less than that of nicotine in the cigarette, but that the stumps contain a larger quantity. On the other hand, the amount of nitrogenous bases present in the smoke inhaled from a pipe is greater than the quantity of nicotine in the tobacco, increasing as the length of the pipe is shortened. The inhaled part of the pipe smoke is free from hydrocyanic acid, but cigarette smoke contains a small amount of this substance similar to the value (0.0019 per cent. on the original tobacco) previously found for cigar smoke (cf. AXALYST, xxvii., 322). A. G. L.