REDUCTION OF IODATES, BROMATES AND CHLORATES, TO IODIDES, BROMIDES AND CHLORIDES. While the usual process for the reduction of these salts consists in fusing them, either alone, or with charcoal, G. Pellagri proposes to use a method based on the fact that potassium iodate in dilute solution is reduced by shaking with iron filings, or zinc powder (not copper or tin), and that these latter metals become oxidized. Shaking the solution, while hot, with iron filings produces complete reduction, and there is neither any iodine carried down with the preipcitate, nor will there be any iron in solution. In too concentrated solutions, as soon as a large quantity of ferric oxide has been thrown down, the latter may again have an oxidizing effect upon the potassium iodide. In this case a complete reduction of the iodate can be accomplished only by filtering repeatedly and treating with fresh iron filings. This oxidizing action of ferric oxide was confirmed directly with pure potassium iodide. But even a concentrated solution of an iodate may be entirely reduced in the cold by introducing into the liquid an iron plate and a copper plate, connected outside of the liquid by a wire, forming a galvanic element. In this case the iron alone becomes oxidized, but on account of the small surface it takes several days to complete the reduction. Towards the end of the reaction a greenish deposit of a mixture of ferrous and ferric oxides is thrown down, which is converted into red oxide by adding a little more iodate solution. This process, which may be used in working on a large scale, involves neither loss of iodine, nor contamination with iron or copper. Zinc, in powder, acts, in the beginning, more powerfully than iron, but complete reduction can only be obtained by means of a zinccopper element. Potassium bromate is similarly reduced to bromide by the iron-copper elements, and the same greenish compound marks the end of the reaction. Potassium chlorate, in warm aqueous solution, is likewise reduced to chloride by shaking with iron filings; but the iron-copper or zinc-copper elements act upon chlorates very slowly, and do not entirely reduce them.—Ber. d, d. Chem. Ges., 1875, 1356, in New Remedies. CARBOLEUM.* Another of Faraday's discovories, that of liquid carbonic acid gas, seems likely to bear practical fruit, if the French patent of a certain Dr. Bains, a Dutch chemist, should prove equal to the anticipations of its inventor. According to him, when bicarbonate of *Chemist and Druggist. soda or potash is warmed in a closed space the carbonic acid can be disengaged and collected in a chamber at any tension whatever. Thus, for example, by heating to 300° or 400° C., the carbonic acid is obtained at 50 or 60 atmospheres, and condenses into a liquid condition in the reservoir at the ordinary temperature. This product is called by the inventor carboleum. In order to employ this liquid for the production of motive power, a result which Faraday himself foresaw, it would be necessary to warm it again, and according to the Moniteur des Produits Chimiques, from which we gather the outline of this invention, Dr. Bains calculates that 16 litres of carboleum produced as above would yield power equal to that of one horse for one hour, or 270,000 kilogrammetres, and that the vaporization of that carboleum during the hour would require at the most 3 hectogrammes, or something less than three-quarters of a pound of coal. The vapour, it is said, could be again condensed by suitable apparatus, and thus the problem of perpetual motion would be in a sense resolved. From the slight account of this invention which we have quoted, it is difficult to understand what is the precise novelty of this invention. Faraday's own process was to heat bicarbonate of soda in a bent glass tube, closed at both ends, collecting and condensing the gas in the shorter leg, and Thilorier constructed an iron apparatus on a similar principle. The gradual development of vapour, and the danger of bursting the resorvoirs, have hitherto prevented the employment of this product in the manner suggested. If Dr. Bains has overcome the difficulties of applying the liquid carbonic acid gas so as to give us a new motive power, he has indeed accomplished a great work; but we fear this remains to be done. It is said, however, that he has lately had an apparatus constructed in Paris for the production of carboleum according to his system, so we may perhaps hear more of it. GINGER-BEER OR "POP."-Take sugar 3 lbs. ; bruised ginger, 2 oz ; cream of tartar, I oz.; lemons, sliced, 4; yeast, 8 fluid oz. . boiling water 4 gal. Pour the water upon the first four ingredients; infuse for two hours and strain; then add the yeast, and when fermentation has fairly set in, pour into strong bottles and wire down the corks. Spruce Beer.Sugar, 6 lbs.; essence of spruce, 4 oz. ; boiling water, 10 gals. ; yeast, 8 fluid oz. Add the water to the sugar and the essence, and ferment with the yeast, and bottle as above. Root Beer.-Take Fl. ex. American sarsaparilla, 6 fl. drs.; fl. ex. pipsissewa, 4 fl. drs. ; fl. ex. wintergreen, 2 fl. drs.; root-beer flavoring, 1 fl. oz. ; refined molasses, I gal.; water, 9 gals. Mix introduce into a soda-water fountain, and charge with carbonic-acid gas in the usual way. Root-Beer Flavoring.-Oil of winter green, 4 fl. drs.; oil of cloves, I fl. dr.; oil of sassafras, 2 fl. drs. ; alcohol, 4 fl. oz.-Drug. gists' Circular. Editorial. THE HEALING PRINCIPLE OF ARNICA. Many physicians are sceptical in regard to the virtues of tincture of arnica as an external application. It has been said that a mixture of spirit and water-of a strength similar to that of the tincture or even simple water itself, are quite as efficacious as the officinal preparation. Experiments in support of this are not wanting; as those performed in one of the Paris hospitals, in which tincture of arnica, spirit and water, and simple water, were employed as external applications under conditions as nearly as possible alike. In these the water dressing came out victorious. Nor are authorities wanting: Hebra, Fox, and White hold to a similar view, as also Dr. W. G. Smith, in a recent paper in the Dublin Medical Record. On the other hand, in favor of the drug, we have the evidence of many physicians, and also the testimony of the public, or, as the learned doctors put it, "what the old women say." The experience of the latter class has seldom much weight with the regular profession, but, in regard to the effect of an application so simple, it may be maintained that an intelligent public have some right to express an opinion. Dr. Johnson once said that to judge whether a table be a bad or good one a man need not necessarily be a carpenter, and we think the observation may legitimately be made to apply to the case of the efficacy of arnica. Viewing the question in this light, we find that there is a vast preponderance of evidence in favor of the drug. In Phillips's Materia Medica, published in 1874, are some statements which have been instrumental in the revival of a discussion of this subject, and also in advancing some new views regarding the peculiar principle to which the action of the drug is to be attributed. "The ingredient in arnica long supposed to be of most consequence was arnicine, an amorphous bitter substance, almost insoluble in water, but freely soluble in alcohol and ether; or else the etherial oil which is also insoluble in water. For a variety of reasons it is now probable that neither arnicine nor the oil, but trymethylamine, an organic alkali, is the really useful constituent of arnica. Trymethylamine, C,H,N, is a clear, colorless fluid, very volatile, and freely soluble in water, alcohol and ether. "The external effect of arnica involves important questions; for, while it is known that many persons have found it an excellent application for bruises and for wounds, other observers have complained that it produces either an actual erysipelas, or a peculiar violet-colored eruption, attended by great heat and pain. I venture to affirm that these are physiological consequences of the alcoholic, and not of the aqueous solution, which latter contains neither arnicine nor the oil. I have never seen inflammatory consequences follow the application of the purely aqueous lotion to wounds or bruises. For external bruises and cuts arnica is, undoubtedly, very useful; and, as already observed, the mischances that have attended its use have probably resulted from the fact that the tincture, containing arnicine and the volatile oil, has been employed. The infusion or decoction alone should be used, and it would be better to give up employing all liniments and lotions in which the tincture is present." With the statements above expressed the London Medical Record, the Philadelphia Medical and Surgical Reporter, and other journals at once coincide. We cannot, however, agree with our contemporaries in their hasty abandonment of a stable and eligible preparation for the inelegant and changeable infusion or decoction, a form of all others most prone to decomposition. It has not been proved that any ill effects which have attended the use of tincture of arnica are chargeable to its characteristic alkaloidal or volatile constituents, and as trimethylamine is soluble in alcohol and water, it would be contained in the tincture as well as in the aqueous preparations which are recommended. It has often occurred to us that the alcoholic strength of the tincture might, with advantage, be reduced to that of diluted alcohol U.S.P., or, at most, to that of proof spirit B.P. Tincture of this strength would be decidedly less stimulating, and perhaps better fitted to represent what might be termed the peculiar specific action of the drug. If the healing power of arnica depends altogether on the presence of trimethylamine, why not use as a liniment, or external application, a simple solution of this substance. Its vile and disgusting odor would, indeed, prove a bar to extended popularity, but its medicinal activity might in some measure make up for this serious obstacle. We are not aware on what grounds it is claimed that trimethy |