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added, and is removed in the same way four times. A drop of barium chloride throws down any traces of sulphuric acid still left. The ethereal solution can then be poured off alone on to a filter, and the determination completed as usual.

M. J. S.

To

New Method of Estimating Fat in Milk. By A. CRONANDER (Bied. Centr., 1886, 706—707).—By the new process, the fat in 40 samples can be estimated in six hours. 100 c.c. of milk is mixed and shaken up for an hour with 10 c.c. of aqueous potash (100 grams KHO in 500 c.c. H2O) and 30 c.c. of moist ether. After to 1 hour, the ether will have dissolved out all the fat; the several ethereal solutions may then be simultaneously evaporated on a specially constructed water-bath at 60-65°, and finally heated at 80° for hour. measure the volume of the fat, the flasks containing the fat are fitted with corks, through which pass two tubes, of which the one graduated to fractions of cubic centimetres passes only just through the cork; the other passes nearly to the bottom of the flask. Water is then passed into the flask by the longer tube, so that the layer of fat rises and fills the graduated tube, where it is measured. This measurement gives volume per cent., from which the weight per cent. is calculated, according to the following table:

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The results are fairly accurate, but as the measurement is made at 35°, the percentage is slightly low (0.01-0.05 per cent.).

E. W. P.

Butter Testing. By J. SKALWEIT (Analyst, 11, 90-91).—It is suggested to employ dialysis in butter testing, inasmuch as the glycerides of the soluble butter acids dialyse much more quickly than the other glycerides contained in butter. The examination of the purified fat in an Abbe's refractometer is recommended as especially worthy of attention. The following tables gives the angles obtained by examining various fats at 20°, water = 1.333 :—

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Genuine Gloucester butter (mean of two experiments) 1-4655

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Butter Testing. By H. HAGER (Chem. Centr., 1886, 495).The author recommends the Reichert-Meissl method of examining butter, the chief feature of which is a determination of the volatile fatty acids. The method is simpler and more expeditious than Hehner's. The butter is filtered and 5 grams are saponified with pure sodium hydroxide (2 grams) in presence of alcohol (80 per cent.). volatile fatty acids are separated by decomposition with sulphuric acid and distillation, and estimated by titrating the distillate with decinormal alkali. The following table gives the number of c.c. of the latter required to neutralise the distillate in the case of certain typical fats :

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Butter Analysis. By F. W. A. WOLL (Zeit. anal. Chem., 26, 28— 33). To ascertain the degree of accuracy with which the percentage of true butter in butterine could be determined by Köttstorfer's and Reichert's methods respectively, the author made mixtures of "oleo-oil" and genuine butter, containing 20, 40, 50, 60, and 80 per cent. of the latter, and analysed each mixture by both methods. The genuine butter employed being one requiring a low percentage of alkali (222-2-223-2 mgrms. per gram), the use of Köttstorfer's mean value, 227, indicated in all cases too low a percentage of real butter, the maximum error being 16.1, and the average error 6.5 per cent. Reichert's method (employing the mean factor 73) gave much closer numbers (maximum error 45 per cent.). (See Abstr., 1879, 406, 983.)

A low specific gravity is a valuable indication of adulteration, most of the materials used in making butterine having a sp. gr. below 0-90536, whilst that of genuine butter is generally between 0.914 and 0.912.

The results of the examination of 37 samples of butter, butteriue, and butterine materials are given. M. J. S.

Reichert's Method of Butter Analysis. By H. B. CORNWALL and S. WALLACE (Chem. News, 54, 315-316).-Reichert's method is very highly recommended. The authors recognise the fact that the proportion of volatile fatty acid varies considerably in different pure butters, and are therefore of opinion that the products of single cows only should be taken into consideration when establishing standards. From this standpoint and from numerous observations, they consider that the minimum standard should not exceed 11 c.c. of decinormal alkali consumed in Reichert's method when 2.5 grams of fat are employed. Moreover, they note that there is no apparent connection between the number of c.c. of decinormal alkali used and any of the following conditions: season of the year, breed, food, age of cow, or time after calving.

The authors' average was 13.68 c.c. decinormal alkali. These results and conclusions differ from those obtained by Munier (Abstr., 1883, 247), D. A. L.

Carrot Colour in Butter. By R. W. MOORE (Analyst, 11, 163— 164). When fat coloured with carrot is dissolved in carbon bisulphide and mixed with alcohol, two layers form, the carbon bisulphide solution being yellow, the alcoholic colourless. On adding a drop of dilute ferric chloride, insufficient in itself to colour the alcohol, the carbon bisulphide becomes gradually decolorised, whilst the alcohol becomes distinctly yellow. Beef fat, mutton fat, olive oil, lard, and butter coloured with carrot all respond to this test. Natural uncoloured butter is not decolorised in this manner.

D. A. L.

A New Ureometer. By J. MARSHALL (Zeit. physiol. Chem., 11, 179-180).—A new apparatus for the estimation of urea by means of the sodium hypobromite method is described and figured. It is a modification of that devised by Greene, the chief difference being that the graduated tube can be easily removed and cleaned.

W. D. H.

Separation of Nitrogenous Substances by Means of Phosphomolybdic Acid. By A. HIRSCHLER (Zeit. physiol. Chem., 11, 25-40).-Phosphomolybdic acid precipitates proteïds, peptones, gelatin, xanthine, guanine, hypoxanthine, adenine, and creatinine. It does not precipitate aspartic acid, leucine, glycocine, urea, or creatine. In order to make quantitative analyses of nitrogen by Kjeldahl's method, it is not necessary that the phosphomolybdic acid should be first removed if excess has been employed. Proteïd, peptone, and propeptone are, moreover, completely precipitated by this reagent; this precipitate does not carry down with it any leucine or other substances which are not usually precipitated by

the acid.

Applying this method for the detection and estimation of leucine in peptic digestion, the teaching of Hoppe-Seyler is confirmed, namely, that a small amount of leucine is formed from proteïd during that process, but much more slowly than in pancreatic digestion.

In experiments on the composition of the liver of animals (dogs) poisoned by phosphorus, it was found that in certain cases of typical phosphorus poisoning, the formation of amido-acids either does not take place at all, or only to a very slight extent. W. D. H.

Opium Testing. By E. DIETRICH (Arch. Pharm. [3], 24, 1023— 1024)-6 grams of air-dried opium powder is macerated with 60 c.c. of water with occasional shaking during 12 hours and then filtered; 50 c.c. of the filtrate is treated with 2 c.c. of normal ammonia, well mixed and immediately filtered through a ribbed filter. 44-2 c.c. of the filtrate, 4 grams of opium, is placed in a tared Erlenmeyer's flask with 10 c.c. of ether and agitated with a swinging motion for a minute; 4 c.c. of normal ammonia is now added, well mixed by swinging, and

the flask allowed to remain six hours. The ether layer is now carefully passed through an 8 cm. filter; 10 c.c. of ether is added to the flask, shaken for a moment, and also passed through the filter. The crystals adhering to the flask are washed down by means of the aqueous solution in the flask, which is passed through the filter; the flask and filter are then twice washed with 5 c.c. of water saturated with ether. After well draining both filter and flask, they are dried at 100°, and the contents of the filter are brushed into the flask, which is dried and weighed until constant. In the case of opium extract, 3 grams is taken, dissolved in 42 c.c. of water, allowed to remain for an hour, treated with 2 c.c. of normal ammonia and filtered; 317 c.c. of the filtrate (= 2 grams of extract) is treated as above with 10 c.c. of ether and 4 c.c. of normal ammonia. In the case of Tinctura opii and Tinctura opii crocata, 50 grams of either is evaporated to one-half, the original weight made up with water, 2 c.c. of normal ammonia added, and filtered; 442 c.c. of the filtrate is treated as above. The method requires little time, is easily carried out, gives a sharp separation of the various constituents, gives very uniform results, and yields almost the whole of the morphine. J. T.

Microchemical Detection of Tannin. By J. W. MOLL (Ann. Agronom., 12, 496).-Portions of the plant cut into small pieces are placed in a saturated solution of copper acetate (7 per cent.) and allowed to remain for 7-10 days. Sections are made and placed in a drop of acetate of iron of 0.5 per cent. strength for a few minutes, they are then washed with water and transferred to a glass containing alcohol in order to expel the air and to dissolve out the chlorophyll, afterwards they are placed in glycerol for observation. The tannin is precipitated by the copper acetate, and the precipitate is stained green or blue by the iron salt, so that these two classes of tannins can be readily distinguished. J. M. H. M.

Tannin Determination. By E. B. (Zeit. anal. Chem., 25, 527528). The author having been unable to obtain the hide powder required for v. Schröder's method, has employed a solution of ferric acetate, which, when added in excess, throws down all the tannin and gives a clear filtrate fit for titration with permanganate in the usual way. The solution contained 48.2 grams of iron alum, 25 grams of sodium acetate, and 40 c.c. of 50 per cent. acetic acid in a litre. He requests chemists who are in the habit of using hide powder to make comparative determinations with this precipiM. J. S.

tant.

Thalleïoquinine Reaction. By E. MYLIUS (Chem. Centr., 1886, 602-603).-About 0.01 gram of the salt to be tested for quinine is treated on a watch-glass with about the same bulk of potassium chlorate and a drop of strong sulphuric acid; ammonia is then added in excess, and the whole stirred, when the solution assumes a darkgreen colour. Less than a milligram of quinine can be easily detected by this reaction.

L. T. T.

Analysis of Pepper. By C. HEISCH (Analyst, 11, 186—190).—It is noted that sand, &c., should be regarded as an adulterant of ground pepper, since almost all sand is removed when the peppercorns are properly cleansed before grinding. The organic matter of pepper should consist of not less than 50 per cent. of starch, which is easily distinguished under the microscope owing to the smallness of the grains; long-pepper starch-grains are, however, very similar to rice starch, but as long-pepper costs nearly as much as good black pepper, it would scarcely be used as an adulterant, and rice with its large proportion of starch could not well be mistaken for pepper. Results of several analyses of pepper are given, including water, ash, starch, alcoholic extract, piperine, &c.; the starch being estimated by boiling with 10 per cent. hydrochloric acid for three hours and polarising. (With regard to the last point, compare Harvey, this vol., p. 125.)

D. A. L.

Hæmatoscopy; a new Method of Blood Analysis. By HÉNOCQUE (Compt. rend., 103, 817-820).—The hæmatoscope is a small, wedgeshaped glass cell on which is etched a millimetre scale, by means of which the thickness of the layer of liquid at any point is ascertained. The blood to be examined is placed without dilution in the hæmatoscope, and the thickness of the layer which shows both absorptionbands of equal intensity is determined. The percentage of oxyhæmoglobin is then ascertained from special tables.

The time of reduction of oxyhemoglobin is determined by examining the spectrum of the blood under the thumb-nail. With a direct vision spectroscope the first and sometimes the second band of oxyhemoglobin can readily be seen. If a ligature is tied round the phalanx, the bands gradually disappear, and the time required for their disappearance after the ligature is tied, is called the time of reduction. varies from 25-90 seconds, the mean duration for a healthy person in a state of repose being 60 seconds.

This time

Activity of reduction is measured in the following manner. In a healthy man, with blood containing about 14 per cent. of oxyhæmoglobin, the time of reduction is 70 seconds, from which it is calculated that 0.2 per cent. of oxyhæmoglobin is reduced per second. This quantity is taken as the unit activity of reduction, and the activity corresponding with various times of reduction and percentage of oxyhæmoglobin as determined by the methods just described is obtained by means of the expression

Activity of reduction e = quantity of oxyhemoglobin x 5.

time of reduction

C. H. B.

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