This fact was first observed while analysing the ashes of a plant which was fused with carbonate of soda for the purpose of estimating the phosphoric acid. The fused mass was thrown into about 4 oz. of water, and digested at about 180° Fahr. for a couple of hours; the insoluble portion was separated, and treated with an acid, when to my astonishment it dissolved with but a very slight effervescence, in fact with the escape of only a bubble or two of gas, the carbonate of lime expected not being present. It was known that this circumstance could not arise from a want of decomposition of the original matter, as it was kept fused for half an hour with 4 times its weight of carbonate of soda; therefore the only rational conclusion was, that the phosphate of lime was in the first case decomposed by the soda, but was subsequently re-formed upon treating the fused mass with water. This has been verified by direct experiment.

12 grs. of neutral phosphate of soda and 6 of carbonate of lime were digested for 2 hours in 4 oz. of water at 180° Fahr., when the carbonate of lime was found almost completely decomposed, and the clear solution upon evaporation furnished carbonate of soda.

6 grs. of precipitated carbonate of lime added to a solution of 20 grs. of phosphate of soda (equivalent proportions of each) in 1 oz. of water were kept in a vial for one month, the temperature never exceeding 65° Fahr. At the expiration of this time the insoluble portion contained 3 grs. of phosphate of lime, corresponding to a decomposition of about 24 grs. of the carbonate of lime; the soluble portion indicated a corresponding portion of carbonate of soda.

Other insoluble carbonates were experimented with, as the carbonates of magnesia, strontia, baryta and lead; the results were the same, differing only in degree. Even hydrated alumina decomposes slightly the phosphate of soda when boiled with it for a length of

time.

I tried two other neutral salts, the acids of which produce insoluble salts with lime, to see if they would act in the same way. The chromate and the tartrate of potash were digested a length of time upon the carbonate of lime, but no decomposition ensued.

I shall not attempt to seek for an explanation of this at present, but shall go on collecting facts of a similar character, to endeavour to find out some general principle that may operate in this and in other cases. This fact itself would not be published at the present time, if it were not of the greatest importance to put analytical chemists upon their guard; for but a few days ago an individual wrote to me, that he was estimating the phosphate of lime in a certain class of bodies by fusing them with carbonate of soda, which will certainly be productive of some error; and although it is to be regretted that our methods of arriving at phosphoric acid in analysis may be diminished by this fact, still it will only stimulate us to find out some other to solve this, one of the most difficult and annoying problems in analytical chemistry.-Silliman's Journal, Jan. 1845.

On the Separation of the Oxide of Cobalt from the Oxide of Manganese. By M. CLöz.

This process, which may be employed with advantage in separating a small quantity of oxide of cobalt contained in certain oxides of manganese, consists in treating the perfectly neutral metallic solution with an excess of the persulphuret of calcium or potassium. The sulphuret of cobalt dissolves entirely in the reagent; the sulphuret of manganese, on the contrary, is entirely insoluble.-Journ. de Pharm., Feb. 1845.

On a new Test for Bile and Sugar. By Dr. M. Pettenkofer.

The phænomena about to be described, and of which an abstract was given in a former Number of this Journal (vol. ii. p. 468), were discovered by the author in studying the products of decomposition of the bile; the accuracy of this test depending upon several collateral circumstances relating to the purity of the reagents and use of proper proportions, we have deemed it necessary to notice these at greater length.

The author remarked that when ox-gall had been treated with sugar, and concentrated sulphuric acid was added until the precipitated choleic acid had begun to redissolve, the mixture became considerably heated, and the liquid assumed a deep violet tint, similar to that of hypermanganate of potash. It was at first considered that this remarkable alteration might depend upon the decomposition of the biliary colouring matter; but it was found equally to occur, nay even more evidently, with the bile which had been decolorized, and with pure biline obtained by Berzelius's method. All the attempts to separate the new product in an isolated state have hitherto completely failed. The author consequently confines his observations. to the application of this phænomenon as a test (a) for bile (choleic acid), and (b) for sugar. The following is the method of proceeding:-A small quantity of the liquid supposed to contain the bile (if the substance be solid it must be treated with alcohol, and the solution evaporated) is poured into a test-tube, and two-thirds of the volume of sulphuric acid added by drops. The heat of the mixture must be kept below 144° Fahr., otherwise the choleic acid will be decomposed. From 2 to 5 drops of a solution of 1 part of cane-sugar to 4-5 of water are now added, and the mixture shaken. If choleic acid be present, the violet-red colour will appear more or less distinctly according to the quantity present. The following precautions are however requisite to be attended to:-1st, the temperature must not exceed that mentioned to any extent, otherwise the colour, although formed, will be again destroyed; 2ud, the quantity of sugar must not be too large, because the colour of the sulphuric solution will become dark brown, and sulphurous acid will be formed, whereby the violet-red colour may be concealed or destroyed; 3rd, the sulphuric acid must be free from sulphurous acid; 4th, if the fluid contain albumen, it is best to coagulate this previously, since

albuminous solutions, although only when very concentrated and when heated with sugar and sulphuric acid, produce a similar colour. It could not be produced with mucous, nor with dilute albuminous solutions, which were always altered to a brown colour; 5th, a great excess of chlorides, although such is rarely found in animal bodies, converted the colour to a brownish red; 6th, if the bile be in very small quantity, the fluid should be carefully concentrated on the water-bath, extracted with alcohol, this also evaporated to a small volume, and the test applied to the cold solution. Sometimes an interval of several minutes is required for the production of the colour, especially when the sulphuric acid is added very slowly, and consequently a lower temperature is generated. In liquids, where the bile is in very small quantity, as in urine, secretions, &c., the author has found it requisite to make a spirituous extract, to evaporate this nearly to dryness on the water-bath, and then to transfer the moist residue into a watch-glass. When quite cold, sulphuric acid and a very small quantity of syrup are added, so that the temperature of the solution remains low. In the course of a few minutes, if the most minute trace of bile is present, the colour is produced. In this reaction, the grape-sugar, starch, or in fact any substance which is convertible into grape-sugar by sulphuric acid, may be substituted for the cane-sugar. The same result was obtained with the bile of man, the fox, dog, ox, pig, fowl, frog and carp. The author concludes from this, that the bile of all the Vertebrata agrees chemically in containing choleic acid combined with soda.

By means of this test the author detected bile in the urine of a patient afflicted with pneumonia. The fæces of a healthy man, when extracted with spirit and treated as above, did not yield the slightest reaction, whilst on adding a little bile previously to the fæces it was perfectly developed. In the stools produced by calomel, several observers have remarked that the green or yellowish-green colour is converted into red by treating them with mineral acids; by applying the sugar and acid, the same phænomena are produced. In all cases of diarrhoea, bile is found in the stools. The author imagines that the alterative effects of purgatives might be thus explained, by their carrying off the bile as fast as it is secreted, consequently preventing its absorption.

Concentrated muriatic acid heated with bile and sugar likewise produces a red colour, but this is much lighter and less beautiful than with sulphuric acid.

This test may also be adopted for the detection of sugar. If sugar be suspected in a liquid, urine for instance, an aqueous solution of ordinary ox-gall is gradually treated with sulphuric acid, until the precipitated choleic acid is again redissolved; the suspected urine is then added, whereupon the violet-red colour is produced. As the quantity of sugar present is usually small, it is best previously to concentrate it. To detect bile in blood, the albumen is first separated by ebullition with spirit, and the concentrated fluid treated as above. If this test is used for sugar, the absence of starch must be previously proved by iodine.

The author thinks his test better than Trommer's in the examination of blood and urine, both because it acts more rapidly and delicately, and because its action is uninterrupted by the ammoniacal salts of the urine, the free ammonia of which retains the proto- and peroxides of copper in solution until it is completely expelled by boiling, whereby the reduction of the oxide of copper may be readily effected by other substances. Pure manna and gall, when treated as above described, afford no trace of the peculiar reaction. It is thus easy to detect grape-sugar in manna.-Ann. der Chem. und Pharm., Oct. 1844.

On Pettenkofer's new Test for Bile. By Dr. W. J. GRIFFITH.

TO THE EDITOR OF THE CHEMICAL GAZETTE.

SIR, Should you consider the following remarks on M. Pettenkofer's test sufficiently interesting, you will oblige me by inserting them. Your obedient Servant,

J. W. GRIFFITH, M.D.

The test proposed by M. Pettenkofer is an exceedingly valuable one, and when applied in conjunction with that of the well-known reaction of acids on the colouring matter, will serve to supply what has hitherto been a desideratum, viz. a ready means of recognising the peculiar biliary and the colouring matters in animal fluids. In a case of jaundice, which I had an opportunity of examining, the urine was of a golden-yellow colour, slightly albuminous, and not containing more than the ordinary proportion of other ingredients; on the addition of nitric acid, the green and red tints were wellmarked, the former exceedingly intense; but on applying the sulphuric acid and syrup as recommended, and adopting the requisite precautions, not the slightest evidence of the presence of the choleic acid could be obtained, nor on analysis by the ordinary methods was I more successful; I therefore consider this a well-marked example (and I have since found another) wherein the biliary colouring matter only was separated with the urine. In examining a number of healthy urines, with a view to test the validity of this purple colour with the acid syrup, I was occasionally much perplexed by finding, on the addition of the acid alone, that the urine assumed a reddishpurple colour, closely resembling the characteristic one, and the subsequent addition of the syrup produced no alteration, thus rendering the test apparently inapplicable. This alteration arises from the action of the acid on the colouring matter of the urine, and may always be distinguished from the true test-colour by allowing the mixture to repose; the choleic purple is permanent, whilst the other is gradually changed to a brown colour. The experimenter will find that where the bile is in very small quantity, a considerable excess of acid will frequently detect it when a smaller quantity will not; the syrup however must be added in very small quantity.

On the Detection of the Constituents of the Bile in Urine.
By M. SCHWERrtfeger.

The author recommends precipitating the urine with basic acetate of lead, as the reaction with nitric acid, when small quantities only are present, is not perceptible. When bile is present, a yellow precipitate is formed with the basic acetate of lead, from which a green solution is obtained with alcohol containing some sulphuric acid, and from which pure alcohol extracts, with the assistance of heat, bilate of lead. It is impossible to conclude, as to the presence of bile, from the colour of the urine, since similar colours may likewise originate from other causes.-Jahrb.für Prakt.Pharm., ix. p.375.

CHEMICAL PREPARATIONS.

Acetate of Iron as a Remedy for Arsenical Preparations. THE hydrated peroxide of iron is of admitted efficacy in cases of poisoning with uncombined arsenious or arsenic acid; but according to the experiments of Duflos, it is quite ineffectual when these acids are combined with bases, as for example, Fowler's solution, or arsenite of potash, or arseniate of potash, which last is frequently employed in calico-printing, and is consequently easily procured.

In the uncertainty in which the practitioner may be placed as to whether the arsenical poison be free or combined, it is very important to administer the oxide of iron in such a form as to produce a favourable result: to this end it is convenient to employ the peracetate of iron.

This compound may be prepared by adding to the hydrated per oxide of iron obtained from the decomposition of four parts of liquid perchloride of iron, three parts of acetic acid of density 1.06, and sufficient water to make up 16 parts.

This liquid, which is a solution of peracetate of iron with excess of base, precipitates arsenious and arsenic acid from all their solutions, either free, or combined with any base; 500 grains of it are sufficient to decompose 1880 grains of Fowler's solution.

This result demonstrates that liquid peracetate of iron merits preference in cases of poisoning by arsenical compounds. It should be remembered that its power is more rapid in proportion as it is more diluted with water; besides which, large dilution prevents all irritating action of the acetic acid set free. -Journ. de Ch. Méd., Novembre 1844, as inserted in the Philosophical Magazine.

[The mode of preparing the above compound is not very clearly stated, for the strength of the liquid perchloride of iron is not given. It may be presumed that peracetate of iron mixed with peroxide is to be employed; the degree of excess of the latter is of little consequence, and the strength of the peracetate is limited by the employ ment of four parts of acetic acid of 106 made up to 16 parts with water, and this, it appears, is to be largely diluted before exhibition. -ED. Phil. Mag.]