here represents only 575.54 gr. of metaphosphoric acid, FeO, 2 HO PO: PO, HO:: 899-28: () 125 : 80 :: 899-28: 575.54 which is all that is requisite to form a soluble salt; the remaining 424-46 gr. of metaphosphoric acid must therefore be excess. To convert 1000 gr. of protosulphate of iron into superphosphate, 347-73 gr. of tribasic phosphate of lime, 3CaO PO, also in the condition of superphosphate (CaO 2HO PO5, 787-44 gr.) must be employed for the removal of the sulphuric acid, as sulphate of lime (CaO, SO, 2 HO). = CaO, 2 HO PO, + FeO SO, 7 HO CaO, SO, 2 HO + FeO 2 HO PO, + 5 HO. 417 3(FeO, SO, 7 HO): 3 CaO, PO, : : 1000: () 5 5 :: 347·73: 787-44 But 347-73 gr. of tribasic phosphate of lime already contains 179-47 gr. of metaphosphoric acid, 3 CaO PO, PO, HO:: 347·73 : ( ) 155 : 80 :: 347-73: 179.44 so then only 820-53 gr. additional of metaphosphoric acid will be necessary to complete the required 1000 gr. In this 820-53 gr. of metaphosphoric acid, first dissolved in 5 f3 of water, dissolves the tribasic phosphate of lime with the aid of heat; to the hot solution then add the protosulphate of iron in powder; when this has been dissolved and decomposed, filter to separate the insoluble sulphate of lime, and when the liquid has ceased to pass, wash the residue several times with small quantities of water. The filtrate now contains the whole of the iron as superphosphate, together with the excess of metaphosphoric acid. Mr. Aitken's formula for 24 f3 of the syrup, provides as fol Accordingly, a solution of superphosphate of iron, representing 1000 gr. of protosulphate of iron, as above described, converted into a syrup of the phosphates, to represent the proportional quantities of quinia and strychnia of the preceding formula, would produce 80 f3 or 5 pints of syrup, with the following requisitions: 640 gr. Sulphate of Quinia, Strychnia, Sugar (as Syrup U. S. P. f3 57-04), 20 gr. 46 3 All that remains now to complete the syrup is the conversion of the alkaloids into phosphates, and their incorporation with the iron solution and the syrup. To prepare the strychnia phosphate requires simply mixture with the iron solution, in which it readily dissolves. But in case of the quinia salt, as the formula precludes the combined sulphuric acid, this must first be removed, which is easily effected by conversion into sulphate of lime by double decomposition with a solution of superphosphate of lime. To accomplish this 75.84 gr. of tribasic phosphate of lime, in the state of superphosphate, is necessary. 3(N2CH2O, SO,8HO): 3 CaO PO, 640 : 40 24 1308 5 155 :: 640 75.84 The tribasic phosphate of lime may now be dissolved in a sufficient quantity of a hot solution of metaphosphoric acid, the sulphate of quinia added and, after complete decomposition, filtering, and the filtrate mixed with the iron solution and the syrup. This operation of separately preparing the phosphate of quinia may be advantageously dispensed with, and the whole process much abridged by transforming the sulphate of quinia simultaneously along with the protosulphate of iron into phosphate, employing the necessary amount of tribasic phosphate of lime, in the condition of superphosphate, to render the decomposition of the two sulphates complete. This process is executed as presented below: Protosulphate of Iron, 1000 gr. 423.57 gr. 781-32 gr. 640 gr. Strychnia, Water, sufficient. 20 gr. 0 41 Dissolve the metaphosphoric acid in 5 f3 of water, heat the solution, and add in succession the tribasic phosphate of lime, the sulphate of quinia, and sulphate of iron; after the last addition continue the heat for a few moments and filter. After washing the residue on the filter several times with small portions of water, add the strychnia to the filtrate, and when this has dissolved mix the solution immediately with the syrup. Thus far the proposed process is a decided success, and an unquestionable improvement in every respect. The complete solution of the phosphates is effected with less than half the prescribed quantity of phosphoric acid. The oxidation of the protophosphate of iron is perfectly prevented (as oxidation by precipitating and washing is unavoidable) and the loss of quinia, by a similar process, is wholly obviated. Hence, practically considered, no loss whatever is incurred in the proposed process, as the crystalline nature of the residuary sulphate of lime permits of almost perfect removal of the dissolved phosphates with a comparatively small quantity of water. And subsequent loss is further avoided by the employment of syrup, thereby yielding a much denser product. But the characteristic feature that condemns this preparation as a failure is its proneness to deposition, which in either process is precisely similar, and in this respect the presence of sugar apparently exercises no preventative influence. The solution of the phosphates without sugar, and tolerably concentrated, retains its transparency for several days, but upon dilution with either water or syrup precipitation immediately occurs. It is very evident, by reverting to previous illustrations, that even a great excess of phosphoric acid does not possess the capacity to preserve the permanency of the solution. Then the direct inference is at once apparent that the excess is superfluous and altogether unnecessaay, and from an economical point of view may consequently be excluded from the formula. Then, after reconstruction, the formula for a solution of superphosphate of iron, containing 1000 gr. of metaphosphoric acid and free from excess of the latter, may be assumed as follows: The manipulations here are in all respects similar to those previously described. The result is a deep green, dense but mobile liquid, which remains permanent for several days, but then becomes subject to the same changes, which take place immediately when much diluted. Addition of excess of ammonia to this solution occasions a bulky greenish-white precipitate, which is again partially dissolved to an intensely green solution, but wholly upon exposure, and only after some time, to a darkbrown liquid. If the solution, previous to the addition of ammonia, has been acidulated with citric acid, no precipitate occurs, but a magnificent emerald green coloration is imparted to the liquid. A similar result is obtained by the addition of citrate of ammonia to the precipitate produced by the previous addition of ammonia to the liquid, but this is again considerably relieved by a sufficient excess of the citrate. If a strictly neutral or slightly acid solution of citrate of ammonia is added to the solution of superphosphate of iron, the transparency of the solution remains unaffected-an immaterial deepening of the color is the only apparent result. The mixture with a sufficiency of citrate of ammonia may be evaporated to a syrupy liquid, from which the dry double salt can readily be obtained in permanent light-green scales, readily and completely soluble in water, and possessing a sweetish pleasant saline, not metallic, taste. The solution of this citrophosphate of iron and ammonia, either with or without an excess of ammonia, will not bear evaporation in contact with sugar-the mixture speedily becoming intensely brown. But when containing no free ammonia it may be mixed with syrup in any proportion-an elegant light-green and permanently transparent syrup being the result. Now, if to the syrup of the phosphates, prepared in pursuance of the proposed formula, or if to the solution, before its admixture with syrup, a neutral solution of citrate of ammonia containing 1000 gr. be added, a beautiful light-green, dense, and permanent syrup will be obtained, which surmounts all those exceedingly perplexing obstacles, and leaves nothing to be desired by even the most fastidious. Very respectfully, yours, A. S. IODINE AND CARBOLIC ACID. BY CHARLES BULLOCK. A solution, containing iodine, carbolic acid and glycerin, Las been introduced to the medical profession by Dr. Percy Boulton, who claims for it therapeutic virtues of superior efficiency. Dr. Boulton's solution is prepared as follows: The iodine color gradually disappears, and the solution eventually becomes colorless. The time necessary to complete this change depends on the temperature-at 60° F. eight to ten days are required; if the cork of the bottle is secured and the mixture exposed in a water bath to a temperature of from 90° to 100° F. the change will be effected in eight or ten hours. The change takes place as quickly in diffused light as in direct sunshine, provided the temperatures are equal. The solution exposed to sunshine becomes somewhat turbid and deposits a muddy precipitate. The change is due entirely to the carbolic acid, glycerin alone, under similar conditions, effecting no change in the iodine solulution, while carbolic acid acts equally well with or without the presence of glycerin. The character of the change is probably the transformation of the iodine into iodide of formyle (iodoform) at the expense of the carbon atoms of the carbolic acid. The solution possesses antiseptic and stimulant properties in a marked degree, and has met with favor as an application in the form of injections, gargles and lotions "in cases of sore throat, ozona, abcesses in the ear, and foul or indolent ulcers." It has also been recommended as an injection in cases of internal hæmorrhoides, and by inhalation for throat and bronchial affections. When used for inhalation the glycerin can be omitted. Philadelphia, June, 1858. |