THE ANALYST. 195 ORGANIC ANALYSIS. The Quantitative Separation of Pyridine Bases from Ammonia and Aliphatic Amines. (Zed. mid. Chew., 1904, xliii., 215-222.)- For the determination of pyridine bases in commercial ammonia 100 to 200 C.C. of the sample are diluted with an equal volume of water, and added to dilute sulphuric acid containing a few drops of a solution of Patent Blue, V.N. (as indicator). The strongly acid liquid is evaporated nearly to dryness and mechanically shaken for ten to fifteen minutes with a sufficient quantity of freshly-prepared sodium bicarbonate solution and an equal volume of ether. The ethereal layer is withdrawn and the aqueous layer again shaken with a fresh quantity of ether. The united ethereal estracts are filtered and thoroughly shaken with an excess of $G sulphuric acid after the addition of a few drops of a 1 per cetit.solution of I’crte?2t IlZue. Sodium chloride is then added in excess, and the liquid titrated back with & sodium hydroxide solution. Under these conditions the end reaction with this indicator is very sharp. I t is advisable to make a third extraction with ether and to titrate the extract as described above, to insure that no pyridine remains in the aqueous layer. The test experiments described show that this method gives accurate results. In determining pyridine bases in ammonium salts 50 to 100 grammes of the finely- powdered salt are treated with 25 to 30 C.C. of water, the solution neutralized, and mixed with a sufficient quantity of pure sodium bicarbonate solution and extrwted J.Milbauer and V. Sta&k.196 THE ANALYST. with ether, as in the case of ammonia solution. If only very slight traces of pyridine are present a larger quantity of the finely-powdered salt should be extracted with hot alcohol, the alcoholic extract acidified and distilled, and the residue treated 8s described above. Salts of pure amines behave like pure ammonium salts in yielding no alkaline base to the ether. C. A. M. The Constituents of the Essential Oil of Californian Laurel. F. B. Power and F. H. Lees. (Proc. Chem. Soc., 1904, xx., 88.)-The Californian laurel, Umbellu- Znriu Califomica (Nuttall), is an evergreen tree growing in California and Oregon. I t is also known as “ mountain laurel,” “cajeput,” ‘( spice tree,” 6 L Californian olive,” “ Californian bay-tree,” and ‘‘ pepper-wood.” The essential oil of the leaves has a pale yellow colour and an odour which is at first agreeably aromatic, but becoming exceedingly irritating when strongly inhaled.I t has a specific gravity of 0.9483 at 16” C. and [ ~ ] , - 2 2 ~ in a 100-millimetre tube. The oil is completely soluble in 1.5 parts of 70 per cent. alcohol, and contains a very small quantity of free fatty acids, including formic acid. The essential constituents of the oil were found to be: cineol, 20; eugenol methyl ether, 10; pinene, 6 ; eugenol, 1.7; and umbellulone, 60 per cent. The latter is a new, unsaturated, cyclic ketone, having the formula C,,H,,O. I t is a colourless liquid with a mint-like odour, having in a marked degree the pungency of the original oil.I t boils at 219 to 220” C., has a specific gravity of 0.9581 at 15” C. and [aID - 37”. Veratric acid and a very small amount of safrol were also present in the original oil. The amount of esters is inappreciable. w. P. s. The Detection of Cryogenin in Urine. R. Courand. (Jount. Pharm. Chim., 1904, xix., 344-347.)-Various colour reactions have been described for the identifica- tion of cryogenin, or metabenzyl-amidosemicarbazide (ANALYST, xxviii., 295 ; xxix., 47), and several chemists have stated lhat its presence in urine is shown by a green coloration with Fehling’s solution. The author, however, has found that an emerald green colour is frequently obtained with normal urines, and not invariably with the urine of those who have taken cryogenin.Of all the recommended reagents the ordinary phosphomolybdic reagent ie the only one that has given satisfactory results in his hands. On adding 2 to 4 drops of this reagent to 10 C.C. of urine containing cryogenin a greenish-blue coloration (with sometimes a blue precipitate) is obtained. For isolation of cryogenin 3 litres of urine are evaporated with neutral lead acetate, the precipitated substances filtered off, and the filtrate evaporated with purified sand. The residue is extracted with chloroform, the extract evaporated to dryness, and the viscous residue extracted with petroleum spirit. The new extract is filtered and the filtrate left to evaporate, first in the air and finally i7z vacuo, until the prismatic crystals of cryogenin are obtained. The most characteristic micro- chemical test for these is the violet colour with green fluorescence given by sulphuric acid containing formaldehyde.THE ANALYST.197 The author's experiments have shown that a single dose of cryogenin is eliminated very rapidly (within thirty hours), but that after continued doses the elimination is very slow. Thus when 0.5 gramme was taken for five consecutive days the drug could still be detected in the urine ninety-eight hours after the last dose. C. A. M. The Determination of Total Carbon in Coal and Soil. S. W. Pam. ( J o P L ~ ? ~ . .i?ncr. Chem. SOC., xxvi., 294).-The carbon is determined volumetrically as carbon dioxide in the residue obtained in the determination of the calorific value according to the author's method (Jozwn.A n w . Chew$. SOC., xxii., 646 ; AKALYST, xxvi., 52). The material is burnt with sodium peroxide, and the resulting mass dissolved in a minimum amount of water. The liquid is boiled for five minutes to decompose the excess of peroxide completely, and is then transferred to the stoppered funnel C (see fig.). The funnel A, of 200 C.C. capacity, contains sulphuric acid of specific gravity 1.4. Acid is run in from A, filling B, which holds 125 to 135 c.c., completely, and to the zero mark at the three-way stop-cock 0 of the jacketed burette P connected with B. Exactly 100 C.C. C of air are then measured in the burette and forced over in the flask B, the greater part of the acid being returned to A. The tap of A is then closed, 0 opened, and the alkaline solu- tion run into the flask.When the liberated gas fills the burette completely, 0 is closed, the gas brought to atmospheric pressure by means of the levelling tube L, the volume read, and the gas discharged into the air, bringing t.he liquid in the burette to the zero mark at 0. The cock is then again opened so as to connect P with B, and the remainder of the alkaline solution is run into B, the con- tents of which are finally heated to boiling. Water is then added through C-until B is completely filled up to the zero mark at 0, and the total volume of gas, ininus the 100 I-i P C L P 3 3 * \ P C.C. of air introduced at the start, is to carbon. A correction must also be calculated made for the carbon dioxide con- tained in the sodium peroxide, which is determined in exactly the same way.All the water used must, of course, be free from carbon dioxide. In the results (ten) given the error ranges from - 0.13 to - 0.87 per cent. For soile, 2 grammes of I n the case of coal, 0.5 gramme is used for each determination.198 THE ANALYST. the sample are mixed with 0-5 gramme sulphur to ensure oomplete oombnstion. The error in ten determinations quoted ranges from 0.00 to 0.13 per cent. A. G. L. The Detection of Urobilin in Urine. L. Grimbert . (Journ. Pharm, Chim., 1904, xix., 425-427.)-Thirty C.C. of the urine are treated with 20 C.C. of Deniges’ mercuric reagent, prepared by dissolving 5 grammes of yellow oxide of mercury in dilute sulphuric acid (20 : 100) and filtering the solution. After standing for five minutes the urine is filtered and the filtrate shaken with 5 C.C.of chloroform. The filtered chloroform extract is then tested with the reagent of Roman and Delluc, which ie prepared by dissolving 0.1 gramme of zinc acetate in 100 C.C. of 95 per cent. alcohol, and adding a few drops of acetic acid. This reagent is added drop by drop to the chloroforni so long as a turbidity is produced, and at the moment the liquid becomes clear the characteristic green fluorescence of urobilin will be observed if that substance is present. The author states that by this method he has been able to detect traces of urobilin in urines rich in biliary products and indoxyl, these compounds being precipitated by the mercuric reagent. C. A. M. The Determination of Halogens in Organic Compounds. H. Baubigny and G.Chavanne. (Bicll. SOC. Chim., 1904, xxxi., 396-401).-The method of deter- mining iodine described by the authors (ANALYST, xxviii., 274) can also be used for the determination of chlorine or bromine, since these halogens are liberated without oxidation, and can be absorbed in a solution of an alkali sulphite. The apparatus recommended consists of a round-bottomed flask, in to the neck of which is ground a series of connected absorption bulbs, whilst a tube, m, n , d, passing nearly to the bottom of the flask, serves for the introduction of air to remove the last traces of chlorine or bromine from the flask. In making a determination, about 25 C.C. of a solution of an alkali sulphite are introduced into the bulb apparatus, and the extremity m of the tube n n’ closed by means of a stopper.From 30 to 40 C.C. of sulphuric acid are then placed in the flask, together with 1 to 1.5 gramme of silver sulphate and 8 to 10 grammes of potassium bichromate, and the whole shaken until the salts have dissolved.. When the liquid is cold, the weighed quantity (about 0.3 gramme) of the organic compound is introduced, and the flask instantly closed. In some cases the reaction takes place spontaneously, but in others the flask must be gradually heated to 135O-14Oo C. in a paraffin bath, the decomposition being complete in thirty to forty minutes. Finally, the last traces of chlorine or bromine are expelled by means of a current of air. In the case of iodine compounds, the iodic acid in the flask is determined as described in theTHE ANALYST. 199 previous commuhicatibn (Zoc. cit.). For the determination of chlorine or bromine, the alkaline liquid in the bulbs is treated with a slight excesB of silver nitrate, then acidified with nitric acid, and boiled until the small quantity of metallic silver formed by reduction of the silver nitrate has been redissolved, and the silver chloride or bromide determined in the usual manner. A series of experimental results is given to show the great accuracy of the method. c. A. M.