of platinum, yellow crystals are obtained, of the form and properties of the double chloride of platinum and kreatinine. Of this platinum salt, 3.3728 gm. yielded on ignition 0:1153 gm. of platinum = 30.92 p. c. This is the same per-centage of platinum as in the double chloride of platinum and kreatinine. A portion of the same salt, burned with oxide of copper, yielded a gaseous mixture, containing for 3 volumes of nitrogen 8 volumes of carbonic acid.* Analysis of This is the same proportion as in kreatinine. 0-1513 gm. of the dried crystals of kreatinine, prepared directly from flesh, yielded 0-2316 gm. of from the carbonic acid, and 0.0865 gm. of water. Hence this substance contains, in 100 parts kreatine juice of flesh. These results leave no doubt as to the nature of this substance, and the occurrence of kreatinine in the organism. The objection, that the kreatinine might have been formed by the action of the free Simple process for ex tracting kreatinine acid in the juice of flesh on the kreatine, during the Now that the nature of this substance, which I at first took for a peculiar base, different from kreafrom flesh. tine, is known, it is no longer necessary to employ the circuitous methods which I was compelled to adopt, in order to prevent all foreign chemical action during its preparation. When the mother liquid which has deposited the inosinates is evaporated to dryness in the water-bath, and boiled with alcohol, all the kreatinine is dissolved, and when chloride of zinc is added to the solution, Pettenkofer's compound is deposited either at once or after some hours, as a crystalline deposit, from which, when acted on by hydrated oxide of lead, pure kreatinine is easily obtained. Lactic acid is a constituent of flesh. Lactic Acid. When the liquid, from which the inosinates have been deposited, is evaporated in the water-bath, and the residue acted on by alcohol, all the lactates are dissolved. If the alcoholic solution be separated from the syrupy viscid liquid which is insoluble in it, and the alcohol distilled off, there is left a yellow syrup which, in the course of 8 or 10 days, forms a soft semi-solid crystalline mass. The crystals which form in it consist of kreatine, and of the potash salt of a nitrogenised acid, differing in properties from inosinic acid; they are contained in a mother liquid, the chief ingredient of which is uncrystallisable lactate of potash. tion To prepare lactic acid from this mass, it is mixed Preparawith its own volume of diluted sulphuric acid (made with 1 vol. of oil of vitriol and 2 vol. of water), or with a solution of oxalic acid of equal strength. Of the latter, so much is added as to produce a crystalline deposit, and, in either case, 3 or 4 times its bulk of alcohol is added to the mixture. cation of acid. By the addition of alcohol, the sulphate or oxalate and purifiof potash is precipitated, while the lactic acid remains the lactic in solution. This solution is mixed with ether till no further turbidity is produced, the liquid is filtered from the deposit, the ether and alcohol are distilled off, and the residue is concentrated in the waterbath to the consistence of syrup. This syrup is again acted on by a mixture of alcohol and ether, half its volume of alcohol being first added, and then 5 times its volume of ether, by which means a nearly pure solution of lactic acid in ether is obtained. The ether is then distilled off and the residue mixed with milk of lime, till it acquires a strong alkaline reaction. The liquid is filtered, and the solution of lactate of lime is left in a warm place, where it soon forms a mass of crystals, which are in themselves colourless, but appear yellow from the adhering Modification of for fish. mother liquor. The mass is diluted with alcohol, and thrown on a filter, where it is washed by cautiously adding cold alcohol so as to displace the mother liquor, till the crystals appear quite white. In order to separate any gypsum that may be present, they are now dissolved in alcohol of 60 per cent., the solution is filtered, treated, if coloured, with blood-charcoal, and evaporated, when it readily yields perfectly pure lactate of lime. From every sort of flesh, except that of fishes, the process lactate of lime may be obtained by this process; but for fish it is necessary to modify it. The liquid, for example, obtained from the flesh of the pike, is evaporated to a syrup, and mixed with an aqueous solution of tannic acid, which causes a thick yellowish white precipitate, softening like pitch when heated. The filtered liquid is concentrated, and treated as above directed with sulphuric or oxalic acid, and at last there is obtained, in the ethereal solution, a mixture of gallic acid (formed by the oxidation of tannic acid) and lactic acid, from which, when the alcohol is expelled, the gallic acid partly crystallises. Without separating these crystals, the acid mixture is saturated with milk of lime, the solution is filtered from the dark brown (nearly black) residue, treated with blood-charcoal, and concentrated, when after a time it yields snow-white crystals of lactate of lime. When the lime is precipitated from the solution of the pure lactate by sulphuric acid, the filtered liquid evaporated in the water-bath, and the residue acted on by ether, pure lactic acid is dissolved, and from this any other lactate may be easily prepared. 1.276 gm. of lactate of lime lost, when heated to Analysis of 212°, 0.323 gm. of water = 25.3 per cent. 1-4735 gm. of lactate of lime lost, when heated to 212°, 0.3805 gm. of water = 25.8 per cent. Gm. p.c. of lime Gm. 0.4870 the lactates prepared from flesh. Lactate of 25.84 lime. =25.54 (horse),, 0.2245 (fox) (pike) = 25.74 Mean proportion of lime in 100 parts of the salt.................................................................. = 25·65 Hence, lactate of lime contains, in 100 parts— Formula of I. II. 1 eq. Lactic acid......... 81 74.32 74.47 74.19 74.46 eq. Lime 28 25.68 25.53 25.81 25.54 III. IV. the anhy 74.26 drous 1 eq. crystallised Lactate of lime 145 100.00 100.0 100.0 0.274 gm. of anhydrous lactate of lime (ox) yielded by combustion with chromate of lead, 0.3335 gm. of carbonic acid, and 0.1152 gm. of water. 0.6420 gm. of anhydrous lactate of lime (fox) yielded 0.7660 gm. of carbonic acid, and 0.274 gm. of water. |