104 THE ANALYST. BACTERIOLOGICAL, PHYSIOLOGICAL, ETC. Methods for the Detection of Blood-Colouring Matters and Similar Substances. 0. Schumm. (Archiv Pharm., 1909, 247, 1-27.)-This paper con- tains in a collected form the various methods which have been proposed for the detection of blood-colouring matters (oxyhEmoglobin, methzmoglobin, and hzmo- globin) and similar substances, such as hmnatin, hzmatoporphyrin, and urobilin. When it is possible to obtain sufficient of the fluid suspected of containing blood, a spectroscopic examination yields most important information ; in the new forms of the instrument, where a layer of the solution 20 cm. in depth may be observed, it is possible to observe the absorption bands due to the oxyhamoglobin of the blood when the latter is present in a dilution of 1 in 25,000.In cases where the oxy- hEmoglobin has been converted into methzmoglobin or hEmoglobin, a, preliminary treatment with ammonium sulphide or oxygen respectively is necessary before the characteristic absorption bands can be observed. No other substance gives a similar spectrum; a very dilute ammoniacttl solution of carmine gives a spectrum which might possibly be confused with that of blood, but a comparison of the two would prevent any mistake being made. The detection of blood in a secretion by means of the microscope is, of course, only possible if unaltered red blood-corpuscles be present. The well-known guaiacum test for blood is extremely sensitive, being capable of detecting 1 part of blood in 100,000 ; but much depends on the kind of turpentine oil used, as well as on the absence of other organic colouring matters, enzymes, etc.The same remarks apply to the aloin test, in which guaiacum is replaced by aloin. A test, proposed originally by Weber, which may be employed for the detection of blood in fzces, consists in treating about 4 grams of the substance under examination with 60 C.C. of a mixture of equal parts of ether and alcohol, filtering, and washingTHE ANALYST. 105 the residue, firstly with alcohol-ether, and then with ether. The residue is well mixed with 4 C.C. of glacial acetic acid, filtered, and washed with a further 4 C.C. of glacial acetic acid. The filtrate is shaken with three times its volume of ether and half its volume of distilled water, the ethereal layer is separated, washed with a little water, and then tested with the guaiacum reagent, with the addition of old oil of turpentine.Faxes containing 0.1 per cent. of blood give a strong reaction, but it is pointed out that the administration of foods containing or consisting of blood preparations (haematogen, etc.) causes the faeces of the patient to give a positive reaction with the test. The benzidine reaction mentioned by Adler (ANALYST, 1904, 29, 227), whilst very sensitive in the case of blood, also gives a reaction with a whole series of other substances, both organic and mineral. A combined chemical and physical test may be employed for the examination of stains suspected to be blood. The stain (on a piece of linen, for instance) is cut out and moistened with a drop of potassium hydroxide solution.After the addition of a few drops of water, the solution is transferred to a small tube (absorption cylinder), a drop of hydrazine hydroxide solution is added, then a layer of ether, and the mixture is examined with the spectroscope, The hEmochromogen formed, if blood be present, exhibits two absorption bands, one between the lines 567 and 550, and the other between the lines 538 and 510. A similar test may be applied to the detection of blood in urine. One hundred C.C. of the latter are mixed with 10 C.C. of a 3 per cent. zinc acetate solution, and heated to a temperature of about 70' C. The precipitate formed, containing the blood-colouring matters, is collected on a filter, extracted with alcoholic ammonium chloride solution, and the extract transferred to an absorption cylinder.One drop of ferrous sulphate solution con- taining tartaric acid is added, and the mixture is examined with the spectroscope. If the urine contains as little as 1 part of blood in 20,000 parts, the spectrum of the hzmochromogen will be observed, The test may also be applied to sputum, stomach contents, bile, faeces, and similar materials. If a drop of blood be mixed with a few C.C. of concentrated sulphuric acid, a solution of hzmatoporphyrin is obtained which shows two absorption bands at the lines 608-509 and 566-544, respectively. Haematoporphyric urines are found after long-continued administration of sulphonal or trional ; these urines are red in colour, but may be readily distinguished from urine containing blood by means of the guaiacum reaction or by Weber's test, and the haematoporphyrin may be detected spectroscopically after treating the urine with zinc acetate as described above.Urobilin, a normal constituent of faeces and frequently occurring in urine, may be detected, in urine, by treating the latter with zinc chloride and an excess of ammonia, filtering the mixture, and observing the filtrate with the spectroscope ; the urobilin-zinc compound shows a band between the lines 519 and 475, and the solution has a green fluorescence. I n the case of faeces, the latter are treated with alcohol containing a few drops of a mineral acid, filtered, and the filtrate precipitated with zinc chloride, w. P. s. The Destruction of Organic Matter in Toxicological Analysis.Kerbosch. (Arclziu Pharm., 1908, 246, 617-620.)-1n testing for metallic poisons in animal106 THE ANALYST. organs, etc., the destruction of the organic matter is best attained by means of a, mixture of equal volumes of sulphuric and nitric acids. The substance to be examined should be ground with water to a paste, and transferred to a tubulated Jena-glass retort, which should have a capacity about four times greater than the volume of the paste introduced. A quantity of the acid mixture is then added, as many C.C. of the mixture being used as corresponds with the weight of the dry sub- stance in grams, and after the reaction has somewhat abated, the whole is heated gently, a further quantity of nitric acid being added drop by drop by means of a tapped funnel fitted in the tubulure of the retort.The stem of the funnel should reach within about 0.5 cm. of the bottom of the retort, and, if a small bulb is blown on the stem just below the tap, a sufficiently tight joint is formed at the tubulure. The temperature and the addition of the nitric acid must be so regulated that lumps of carbonised matter do not form, After a time a yellow solution is obtained with a, layer of fat floating on its surface ; on raising the temperature and continuing the addition of nitric acid, the fat is decomposed gradually, and the resulting dark- coloured liquid is further heated until colourless. If most of the excess of sulphuric acid be evaporated, the residual solution resulting from the destruction of 250 grams of flesh need not be more than a few C.C.w. P. s. Volumetric Estimation of Potassium in Liquids of Animal Origin. W. A. Drushel. (Zeits. Anorg. Chem., 1909, 61, 136-146.)-Animai liquids free from albumin (urine) are ashed by evaporating them to dryness and treating the residue with a mixture of 9 parts of nitric acid and 1 of sulphuric acid, at first in a covered and finally in an open dish. Other animal liquids (blood, serum, lymph, milk) are evaporated and treated first of all with bromine, or, cautiously, with nitric acid alone ; after further evaporation and charring of the residue, oxidation of the organic matter is completed by gentle ignition with sulphuric acid, In any case the inorganic residue is treated with a few drops of acetic acid and a little water.An excess of sodium cobaltic nitrite is added to the unfiltered solution, and the whole evaporated nearly to dryness. The cold residue is mixed with sufficient cold water to dissolve the excess of the reagent, filtered through asbestos, and washed with a saturated solution of sodium chloride diluted with its own volume of water. Filter and precipitate are transferred to a beaker and heated with an excess of a standard solution of potassium permanganate and a little sulphuric acid until the precipitate is completely oxidised. A small excess of oxalic acid is then added, and the excess titrated back with permanganate solution. As the formula of the precipitate is K,NaCo(NO,),, H20, 1 C.C. of a & solution of potassium pernianganate corresponds to 0.000857 gram K,O.The results obtained by the above method are practically identical with those given by the Lindo-Gladding method, the maximum difference being about 1 per cent. on the potassium oxide. A. G. L. The Use of Silver Salts in the Sterilisation of Water. F. Traetta-Mosca. (Gazz. Chim. Ittal., 1909, 39, 69-109.)-1n the author’s comparative experiments described in detail, 100 C.C. of sterile water were inoculated with 3 to 4 drops of an emulsion of a culture of various bacteria (Racillw szdtilis, B. coli, B. typhosus, etc.),THE ANALYST. 107 15 minutes ... 30 9 9 ... 1 hour ... ... 3 hours ... ... and 1 C.C. added to sterilised distilled water, containing a definite quantity of the silver salt. One C.C. was withdrawn at intervals, and cultivations made in Petri dishes.I n a typical experiment with B. coli, the following results were obtained after the addition of silver perchlorate in proportions of 1 in 10,000 to 1 in 500,000 : ~ 0 18 100 500 0 10 18 200 0 2 10 21 0 0 2 5 NUMBER OF COLONIES. 800 300 23 10 Duration of Action. 1 : 10,000 1 : 25,000 1 : 50,000 1: 100,000 1 1 1 1 800 ’i: ),,, 10 All the silver salts (fluoride, chlorate, perchlorate, 1 : 250,000 1 : 500,000 Control. I 1 sulphate) had pronounced bactericidal properties, and in the author’s opinion are suitable for sterilising water for drinking purposes. The bactericidal action is mainly due to the silver ions, and even when the silver is apparently precipitated completely by a chloride, it still retains a sterilising effect, which the author attributes to a minute quantity of the silver chloride remaining dissociated, or possibly to its remaining in suspension in a colloidal form, as Paterno and Cingolani (ANALYST, 1907, 32, 294) found to be the case with silver fluoride.According to D’Auna the acid radical is only of importance in so far as it reduces the amount of the metal, but the author’s experiments show that a certain bactericidal action must also be attributed to the acid radical. Thus silver chlorate (silver, 56.3 per cent.) and silver perchlorate (silver, 52 per cent.) had a much more energetic action than silver sulphate (silver, 69.2 per cent.). C. A. M. Determination of Total Sulphur in Urine. F. W. Gill and H. S. Grindley. (Journ. Anzer. C7zem. Sac., 1909, 31, 52-59.)-The authors have proved that in the Folin method (fusion with sodium peroxide) there is a loss of sulphur estimated at 10.3 per cent.of the total sulphur present, owing first to volatilisation during fusion, and secondly to the escape of sulphuretted hydrogen on acidification of the melt. If the Folin method be modified so that further small portions of the peroxide are added to the melt before the fusion is ended, the product contains no sulphide, and the second source of loss is eliminated. But even then the loss due to volatilisation is estimated at 6.2 per cent. of the total sulphur. The standard employed for estimating the losses by the fusion method was a method based on that of Konshegg, depending on the acid oxidation of the organic matters by a mixture of nitric acid and potassium nitrate : 25 C.C.of urine are measured into a 500-C.C. Kjeldahl flask, and 10 C.C. of a 20 per cent. solution of potassium nitrate and 25 C.C. of fuming nitric acid, specific gravity 1.53, are added. The flask is placed on asbestos-gauze and heated over an alcohol burner until its contents have evaporated nearly to dryness. The flask is then held in a, hand-clip and moved about over the naked flame until all108 THE ANALYST. brown fumes are expelled and the contents are fluid and colourless. During cooling the flask is rotated to avoid solidification in a mass ; the neck is then washed down with 25 to 50 C.C. of hot water, and 10 C.C. of hydrochloric acid (1 to 4) are added. The solution is transferred to a beaker and diluted to about 200 C.C. If now the sulphate be precipitated direct with barium chloride, the result is too high, owing to the influence of the potassium salt. I n order to counteract this influence, pure sodium chloride in the ratio of 4 parts to 1 part of potassium salt-ie., 8 to 10 grams -must be added; the precipitation is then effected with the usual precautions, forty-eight hours being allowed for the complete separation of the barium sulphate. The purity of the reagents must of course be controlled. The authors refer to the fact that a very large number of recorded analyses of the sulphur in foods and faxes have been based on the alkaline fusion method, and it thus becomes necessary to reinvestigate the question of their validity for purposes of comparison. J. F. B.