74 THE ANALYST. REPORT OF RECENT RESEARCHES AND IMPROVEMENTS IN ANALYTICAL PROCESS. DETECTION OF ROSIN m BEES-WAX. H. ROTTQER (Chm. Zed. No. 4, 91)- Donath’s process : If a sample containing 5-10 per cent. of rosin is heated up to l l O o C, a strong smell of turpentine will be noticed. But pure wax collected in the neighbour- hood of pine woods also emits this odour. If large quantities of rosin are present, any dealer will at once notice this from the very appearance, but small percentages are best detected as follows : if rosin is boiled for some time with strong nitric acid it is gradu- ally dissolved with evolution of nitric vapours. Water being added, a yellowish floculent precipitate is obtained, which is not altered by fixed alkalies, but dissolved in ammonia with a blood-red colour.A nut-sized piece of the wax is therefore boiled in a test-tube with strong nitric acid for fifteen minutes. A little cold water is carefully added t o solidify the layer of wax, so as t o enable t o pour off the acid fluid. On cooling, or better still, an addition of more water, a precipitate is obtained which gives the charac- teristic reaction with ammonia. E. Schmidt’s process: 5 grams. oE the sample are boiled in a flask with 25 grams. of common nitric acid of 1-33 sp. gravity for one minute. An equal volume of cold water is then added, and then ammonia in slight excess. I f now the fluid is poured off from the wax into a cylindric glass, the colour will be yellowish if the wax were pure; but if adulterated with rosin, even with only 1 per cent., the colour will be reddish-brown.It is as well to test a pure sample side by side. Hager’s process : The sample is boiled with 15 times its weight of dilute alcohol (two alcohol and one water). After cooling, the liquid ie poured, or, if necessary, filtered 0% and then diluted with an equal bulk of water. I f rosin is present the liquid turns milky. Stearic acid does not interfere with this test. The German Pharmaceutical Committee recommends to boil the suspected wax with 10 parts of water and three parts of carbonate of soda for 15 minutes. If rosin i d present a per- sistent emulsion is obtained. Sedra proposes the, following process : 3 grams. of the sample are dissolved in a test-glass in 30 C.C. of chloroform, and then shaken with 200 C.C. of lime-water.Pure wax will cause an emulsion, but if rosin is present a turbid yellowish-brown liquid separates out. The author, after trying these processes, utterly condemns the last process, as he failed to dibcover an admixture of even 20 per cent. of rosin. Hager’s process gives satisfactory results, but the author finds that this chemist makes a mistake in supposing the weak alcohol not to affect the wax or any stearic acid which may be present. Traces of these bodies are dissolved, but are dis- tinguished from rosin by quickly collecting on the surface of the diluted fluid. If, how- ever, proof spirit is used, the stearic acid is practically left undissolved, and even 3 per cent. of rosin may be detected. The best plan is, however, to first thoroughly boil the sample with strong alcohol, to evaporate the alcoholic solution, and then to apply Donath’s nitric acid and ammonia test.L. DE K. THE ASSAY OF INDIGO. Dr. FRITZ VOELLER. (Zeitschr. J. Angew, Chemie. No. 4, 91).-The process most commonly employed is the one with permanganate, proposed by Fr. Mohr. The results are, however, often very inaccurate, especially with the inferior kinds of indigo, as these mostly contain other organic compounds, which are alsoTHE ANALYST. 75 oxidised by permanganate. The traders, knowing this, do not scruple to even employ oxalic acid as an adulterant. Another drawback to the process is the difficulty of pro- perly noticing the end reaction on titrating. The same may be said of other processes based on oxidation, such as Bolley’s process with hydrochloric acid and chloride of lime or chlorate of potash, Penny’s process with sulphuric acid and chromate of potash, or Ullgreen’s method with red prussiate of potash. Chevreuil’s process and other similar colour-methods are not criticised, although they do occaeionally good service, they c m scarcely be classed among the anaZyticaZ methods.The reduction processes of Pugh, with sulphate of iron and soda-ley, and hitsche, with glucose, alkalies, and alcohol, whose objects are to reduce the indigo to indigo- white, which may then be re-oxidised and finally weighed, are also likely to give too favourable results, as there is always a chance of the co-precipitation of foreign organic bodies, unless these have been first removed by suitable means.Berzelius found that, besides indigo-blue and some mineral matter, the commercial product contains three other bodies, which he called indigo-gluten, indigo-red, and indigo-brown. The first, which may be extracted with dilute acids, is closely related to vegetable albumen, and precipitated from its solution by alcohol and tannic acid. The indigo-brown, which is soluble in alkalies, is chiefly found in samples in the preparing of which lime has been employed. Berzelius’s plan is to first wash the sample to be analysed with hydro- chloric or acetic acid, then with alkali, and finally with alcohol and hot water, which will remove the three mentioned bodies, and leave a fairly pure indigo-blue; This con- tains, however, a certain quantity of silica or other mineral matter, which the acids and alkali have failed to remove.Although the amount of this mineral matter may be estimated by incineration, the author thought better results still might be obtained by estimating the nitrogen in the purified product by Kjeldahl’s process and calculating from this the percentage of indigo-blue. Por his experiment he used a sample of common Bengalese indigo. The washings with acid, soda, alcohol, and hot water were quickly performed in a perforated crucible, closed with asbestos and connected with a filter-pump. The asbestos containing the indigo-blue was then dried, and finally treated with sulphuric acid and a drop of mercury. The nitrogen multiplied by 9.36 equals the indigo-blue. Pure sublimed indigo-blue showed 99.85 per cent. The common Bengalese sample gave 75.76 per cent.1;. DE. x. VOLUMETRIC ESTIMATION OF PHENOL, THPMOL, NAPHTHOL, AND SALICYLIC AcfD. -J. MESSINGER AND a. VORTMANN have found that the principles of the process by which aristol and similar compounds are obtained-&, treatment with iodim of a strongly alkaline solution of thymol, etc.- .may be applied to the quantitative estimation of the above-named substances, and no doubt also of others chemically allied t o them. The requisite volumetric reagents are, a 23 normal solution of iodine and a & so- lution of sodium hyposulphite. In the estimation phenol. or carbolic acid, the later must be in alkaline soldtion. For each molecule of phenol there will be consumed B atoms of iodine. The mode of pfo- ceeding is as follows : 2 to 3 grams.of the phenol to be estimated are dissolved in soda so that there are at least 3 moleoules of sods present for every molecule of phenol. The76 THE ANALYST. solution is then diluted to 250 or 500 C.C. Of this an exactly measured quantity of 5 or 10 C.C. is put into a small flask, the contents heated to about 60? C., and enough of the -& iodine solution added to render the liquid strongly yellow by excessof iodine. Upon agitation a bright-red precipitate will fall. After the liquid has cooled, it is aciddated with dilute sulphuric acid, diluted to 250 or 500 c.c., and a definite portion (say 100 c.c.) titrated with .i-17; hyposulphite in order to ascertain the excess of iodine. The actual amount of iodine consumed (in grams.), multiplied by the factor 0.123518, gives the quantity of pure phenol.The factor is derived thus : -~ 93'78 = 0.123518 1 mol. phenol - 6 at. iodine 759.24 The analytical data furnished by the authors show that this method of estimation is very satisfactory, differences not exceeding 1.2 per cent. Thymol can be similarly determined, but no heat is required. The precipitate caused by iodine has a brownish-red colour. Each molecule of thymol requires 4 atoms of iodine. The amount of iodine actually consumed, multiplied by 0.2956772 indicates the quantity of thymol. From 0-1 to 0.3 gram. of thymol is dissolved in soda, so that there are at least 4 molecules of soda for 1 of thymol. The solution Is then made up to 250 or 500 c.c , and, except that no heat is applied, treated as in the cme of phenol.Naphthol (6eta).--This yields, under the same conditions, a dirty-green precipitate. Here also 4 molecules of soda must be taken for every 1 molecule of naphthol. The amount of iodine actually consumed must be multiplied by the factor 0.37843106. In the case of naphthol, the solution must be heated to 50° to 60" C. Otherwise the method is the same. Salicylic Acid.-This may be estimated either alone or when mixed with benzoic acid, the later not entering into reaction. In this case, also, 4 molecules of soda must be taken for every molecule of the acid. On adding Ghe & iodine solution to the solution of the acid warmed to 50" to 60° C., a precipitate should not be formed a t once. Only after iodine is present in excess, and the liquid has been again slightly warmed, is there pro- duced a bright-red precipitate, which increases in quantity after acidulation.If too small a quantity of alkali was present, a yellowish-white precipitate is formed before iodine is present in excess. Should this happen, more alkali is added until this precipitate disappears, after which the addition of the iodine solution is continued. The factor with which the quantity of iodine actually consumed must be multiplied is Oi181326O6. If not, the latter must be determined separately by means of the & iodine solution, and the proper correction made when the alkali is employed. Calculations of the results obtained by the above processes may be saved by the following consideration : Letf denote the factor with which the quantity of iodine must be multiplied in each case, and t the titer-that is, quantity of iodine in 1 c.c.-of the iodine solution ; then the product f x t at once shows the quantity of phenol, etc., in grams,, which corresponds to 1 C.C.of the iodine solution.-Berichte, 1890, 2753, and Am. Drug. xx. 56. The alkali which is used in these processes must be free from nitrite.THE ANALYST. 77 MICRO-CHEMICAL INVESTIGATION OF EXPECTORATION. PROF. FERDINAND HUEPPE (Chemiker-Zeitufig, 17th Dec., 1890). The author uses the following apparatus :-(1) A microsoope, which need not as a rule be provided with the strongest powers, then, owing to the staining proceBs, even isolated bacteria are readily recognised. However, it is as well to have a Gz inch power at command. (2) Some salt-cellars and a few crystalisa- tion basins of about 5-6 C.M.diameter, and a depth of 1 C.M. (3) A small pair of bellows connected with a finely drawn-out glass tube. (4) A pair of pincers and a few platinum needles. These are made by fusing into a glass rod of about 20 C.M. length a 5 C.M. long platinum wire. Either before or after use the points must be ignited, and then just allowed to cool. (5) A spirit lamp or a Bunsen-burner. (6) Test-mixers, burettes or pipettes, and a balance. (7) To get a fair sample of the expectoration the author uses a cylindric glass holding about 100 C.C. provided with a ground stopper. To measure off the fluid a pipette is used, capable of accurately delivering *01 C.C. In using the pipette the top must be closed with a piece of sterilised cotton wool, or what is still better, it should be connected with an aspirator. Reagents.-( 1) Recently boiled distilled water, which must be of course perfectly sterilised.(2). Absolute alcohol or 90 per cent. spirit. These are used for dissolving the colours, also to prepare a 60 per cent, spirit. (3). A 5 per cent. solution of phenylic acid. (4). Sulphuric, hydrochloric or nitric acids, diluted with ten times their bulk of water. cent. of alcohol, and 90 per cent. of the carbolic acid solution. first dissolved in the spirit before the carbolic acid is added. many months. They are used for the purpose of decolourising. ( 5 ) To stain the bacilli, a solution is used containing 1 per cent. The The (6). For the purpose of staining are wanted :- of fuchsine, 10 per fuchsine must be solution keeps for (a).Watery methylene blue, which means the solution of the dye in water (which must, however, often be filtered or even renewed), or an alcoholic solution is added to water in sufficient quantity immediately before use. (6). Yellow fluorescine in a saturated alcoholic solution of methylene blue. (c), Picrate of aniline. Aniline oil is saturated with powdered picric acid. A few drops of this solution are added to a small cup full of aniline. The collecting and sending out of the expectoration must be done in thoroughly cleansed glass bottles, provided with ground glass stoppers. The morning product is the best fitted for the experiments, particularly if the patient is improving. For quantitative estimation it often becomes necessary or desirable to specially pi-e- pare the expectoration.A saturated solution of borax is mixed with three parts of water. According to the consistency of the expectoration it is thoroughly shaken in a test-mixer, with an equal or even a, treble volume of the borax solution for about a minute, until all coarse lumps have disappeared. The liquid is then put into a conical glass, and after this is covered over, allowed to settle for 24-48 hours. The clear fluid is then poured off, and the deposit used for the experiment. This complicated process78 THE ANALYST. need only be resorted to when the direct testing of the expectoration has given no satis- factory result. Preparation of the slides. When the expectoration is fresh, a little is taken out by means of the platinum needle ; not the watery fluid but the pus-like part.If prepared a drop is taken by means of the pipette. The material is spread over the covering glass by means of the platinum needle with the utmost care. The layer need not be particularly thin, but must be as much as possible uniform, This may be assisted by the application of a gentle blast of air from the bellows, which will also get rid of the moisture, The cover is got hold of with the pincers and passed three times (the material upwards) through the Bunsen flame. The objects are then ready for staining. A drop of the fuchsia solution is spread over the cover and allowed to act for five minutes ; or the cover is made to Boat on this fluid, contained in a little dish for the same length of time.The time may be shortened to about one minute if the solution is applied boiling hot. After the staining, we must decide whether other bacilli besides tuberculi- bacilli are t o be looked for. Ordinary phthisis is no longer considered to be pure tuber- culose, but a mixed infection. The methods which enable us to detect the other bacteria as well are not, however, so accurate for the detection of the tuberculi-bacilli as the special methods. The excess of colouring matter is carefully removed irom the cover by means of blotting-paper, and the glass is then dipped for a few seconds in the dilute mineral acid, until the colour seems all gone. I f , however, the layer is somewhat thickish, it is as well not to immerse it too long. The covering glass must now be well washed with water and then quickly dried by means or" the bellows.A drop of the picrate of aniline is now put on a slide and the covering glass put on downwards. The excess of aniline is removed by means of blotting-paper, and the outside of the cover is then moistened with a drop of a suitable oil. The objective is now lowered until it touohes the globule of oil, and any exprienced microscopist will soon recognise the tuberculi-bacilli, appearing as they do like red rods on a yellowish field. There is little chance of mistaking them for bacteria. B, Testing for tuberculi-bacilli in presence of other bacteria. The colouring by means of fuchsine and the bleaching by acids is just as in A, The acid must, however, only act for a few seconds, when the slide is immediately immersed into 60 p.c.alcohol, contained in two separate basins, After draining off the spirit a drop of the saturated watery solution of methylene blue is put on, but washed off again after one minute. Its outer surface, after being dried with blotting-paper, is moisteaed with a drop of oil and the microscopical examination is conducted as usual. The tuberculi-bacilli appear red on a blue field, but their number seem to have somewhat diminished. The other bacteria will all be colonred blue, The fixing. Staining, The specimens look most beautiful when stained whilst cold. It is therefore as well to apply them both in succession. A. The operator wants to test for the tuberculi-bacillionly. The cover is now put on a slide wikh a drop of water.THE ANALYST.79 I f one likes to avoid the use of mineral acids (to prevent accidents to the micro- scope) the following process may be recommended : The staining with fuchsine is done as usual, and the cover is then dipped six or ten times in succession into the fluorescin methylene blue then about ten times in a strong alcoholic solution of methylene blue, and finally washed with water. This will also communicate a red d o u r to the tuberculi-bacilli, while other bacteria will look blue. L. DE K. ELDERBERRY JUICE AS AN INDICATOR, BY CLAUDE C. HAMILTON, M.D., Pa. a,- The expressed juice of the fruit of Sambzcscus canadensis, or elder, has a garnet-red colour when neutral or acid, but turns green when alkaline. This property led to some experiments by the author as to its value as an indicator in volumetric analysis. These experiments show the elderberry juice to be not only superior to litmus for any titra- tions, but equal in efficiency to rosolic acid as an indicator in the estimation of ammonia or phosphoric acid.When the indicator is first added to ammonia the colour is a (‘ muddy ” blue, becoming clearer and of a pea-green colour as the acid is added from the burette. This green is brighter and more distinct as the final end to alkalinity approaches, and, when a drop of acid is added in excess, instantly becomes a garnet-red colour. The turn of the indicator was exactly at the number of cubic centimeters required to turn rosolic acid yellow, while phenolphthaleingradually faded out at a few tenths cubic centimeters more.In titrating the precipitate of MgNH,PO, by Stolba’s method, the red colour appears at just twice the cubic centimeters of HCI required to turn rosolic acid yellow. I f the precipitate is dissolved in HCl and the excess measured back by NaHO, the green appears at just twice the cubic centimeters required to turn resolic acid red. At the point where rosolic acid just turns, elderberry juice has a violet colour. Then when the formula is Na,HPO, the elderberry juice is green, and is not restored to acid till the formula is H PO,. The fmal point is more distinct when the MgNH4P04 is dissolved in excess of HCl and the acid measured back by NaHO. The author is engaged on further experiments in regard to the action of this substance with phosphates to deter- mine its practical value.I n titrating carbonates a bluish-violet appears at the point when phenolphthalein is just decolourised (without heating), and changes to red at the same point that methyl orange is turned red. The change of colour is not very distinct, depending on keeping the solution a t a constant temperature. These experiments were made with elderberry wine carefully neutralised with with NaHO. The fresh juice may be pre- served by addition of one-fifth its volume of alcohol. The author finds it quite efficient in all titrations, unlem it be wetic acid, when the colours seem 80 pale ag to be rather hdisfinct.-Am~. Drug, XX., 50. A NEW METHOD OF TESTING HONEY. By Da. OSCAR IJiAENLI.--It is only about five years back that every expert would have condemned as adulterated any honey which was found to turn the ray of polarised light to the right instead of the left.About that time Dr. Haenle succeeded in finding, while travelling, some natural (wild) honey which polarised to the right. This was subsequently ascertained to be due to the fact80 THE ANALYST. that the bees fed upon coniferous products, while those feeding upon flowers produced laevogyre honey. While the polariscope had, before this discovery, been generally used as a certain criterion to distinguish between genuine and adulterated honey, t~ instru- ment could no longer be employed for the purpose without some restriction. The author has now ascertained that if the honey be dialysed before the polarisation test is applied, the result is a certain indication of the character of the honey.I. EXPERINENTS WITH HONEY COLLECTED FROM FLOWERS.-~. A pure Alsatian honey was dissolved in twice its weight of water. The solution polarised 2 8 O to the left (-288). It was then subjected to dialysis during sixteen hours, after which the residue remaining in the dialyser was optically inactive (00). 2. Thirty grams. of a pure honey were dissolved in 150 grams. of water, the solution decolourised and then dialysed. After eighteen hours the residue was inactive. 3. Fifty grams. of a similar honey were dissolved in 250 grams. of water. The solution polarised at-1 l o . After sixteen hours’ dialysis the residue was optically in- active. On further evaporating the latter and again dialysing, its inactivity remained unalterd.11. EXPERIMENTS WITH GLUCOSE SYRUP.-A 10 per cent. solution of glucose syrup which polarised + looo, was decolourised and then dialysed. After sixteen hours it still polarised -I- 58. The residue was then concentrated, aud in proportion as this pro- gressed so rose the angle of polarisation. 111. EXPERIMENTS WITH HONEY PUBPOSELY ADULTERATED.-~. Forty grams, of a pure honey, polarised in a 1 in 2 solution at--35O, were mixed with 10 grams. of gIucose syrup. A 10 per cent. solution of this mixture was subjected to dialysis, and the residue was found to remain dextrogyrate at + 48. 2. Thirty grams. of a pure honey were mixed with 20 grams. of glucose syrup, dissolved in 250 parts of water, and the solution decolourised by charcoal. It polarised a t + 658. After twenty-four hours’ dialysis the residue retained a permanent polari- zation of + 148, After concentrating this residue to half its weight its polarizing angle had increased to + 60°. The solution polarised at + 95’. It was then dialysed and the liquid on the dialyser examined a t intervals of two hours, The following is the rate at which polarisation decreased until it remained constant : 3. Fifty grams, of a glucose honey were dissolved in 250 grams. of water. After 2 hours . . .. , . +45”. ?> 4 9 ) .. .. . . + 3 3 O . > 9 6 > 7 . . . . .. -I-18O. Y 9 8 >) . . .. .. +15? > ? 9 >> . . .. . . +12*. >? 10 >> . . ,. . . +11*. *> 11 > > 1 . . . . . +loo. 79 12 9 ) .. .. . . +loo. Further dialysation did not change the angle (+ 10’). General cocnch8&n~.-Any honey which, after having been dialysed, does not turn the ray of polarised light to the right, is free from glucose. Any honey which, after dialysis, retains a permanent dextrogyre polarisation, contains glucose.-Arner. Drug and Ph. Ztg.