THE ANALYST 429 BACTERIOLOGICAL, PHYSIOLOGICAL, ETC. Estimation of the Formaldehyde evolved by the Disinfectant “ Autan.” G. Fendler and W. Stuber. (Zcits. aizpzo. C l ~ m . , 1908, 21, 2018-2027.)- Autan ” is a disinfectant sold by the Bayer Company, consisting of paraformaldehyde and barium peroxide, together with a little alkali carbonate to control the action. The two main ingredients are packed separately in quantities calculated for the disinfection of rooms of different cubical contents. When required for use, the two powders are mixed together and treated with a definite proportion of water (80 per cent.), which is measured out in the tin can in which the ‘‘ autan” was packed. The room is then sealed, and in a few minutes a violent evolution of formaldehyde and water vapour ensues; the fumes are allowed to remain in the room for five hours. For the valuation of the formaldehyde contents of ‘( autan ” the conditions of the experiment must be adapted so as to imitate thoBe of practical use.A carboy of 75 litres capacity is selected to represent the room, and a waterproof wood-pulp tumbler serves as the reaction vessel. A frame is made of zinc strips to hold the tumbler, and this is attached to a stout wire which passes through the cork of the carboy so that it may be suspended in the closed vessel. The contents of the two packages are weighed separately, sampled, and the samples are mixed in the same proportions as the original weights. For a carboy of the above size about 5 grams of the mixed sample are required. The substance is placed in the tared tumbler, and the aliquot proportion of water required is calculated after determining the volume of the tin measuring can.Three litres of water are placed in the carboy, the necessary430 THE ANALYST, quantity of water is mixed with the ‘‘ autan ” in the tumbler, the latter is inserted in the frame, and this is suspended in the closed carboy at a distance of about 10 cm. above the surface of the water. After remaining for five hours, the wire is pulled up through the cork as far as it will go, the contents of the carboy are swirled round in such a manner that nothing comes in contact with the tumbler, the stopper is with- drawn and quickly replaced by a plain stopper. The tumbler is weighed in order to determine the loss of water plus formaldehyde which has taken place in the course of the reaction, and the contents of the carboy are shaken vigorously.In order to determine the formaldehyde, 150 C.C. of the liquid in the carboy are treated with 30 C.C. of f! sodium hydroxide solution and 30 C.C. of & iodine solution, acidified after five minutes, shaken in a closed flask for half an hour, and titrated back with thiosulphate. The quantity of formaldehyde found is then calculated in terms of the number of grams evolved per cubic metre of nominal disinfection capacity of the package; this should be about 2.1 grams per cubic metre; the quantity of water evaporated ia about 13-15 grams per cubic metre. J. F. B. Quantitative Estimation of Albumin in Urine. A. Jolles. (Chem. Zeit., 1908, 21, 917.)-For the estimation of albumin in urine the gravimetric method of Scherer gives the most accurate results, but in the case of urines containing mucus or pus the filtration is very difficult, and often impossible.Esbach’s clinical method is e v p more difficult in such cases, and frequently no precipitate is formed at all. The author has found that by the use of suitable quantities of a mixture of 50 C.C. of 1 per cent. acetic acid, 50 C.C. of commercial formol, and 15 grams of common salt, the precipitation of albumin is complete, and the estimation may be made even in the most difficult cases. In carrying out this estimation, 100 C.C. of the liquid are placed in a beaker of about 200 C.C. capacity, and neutralised, if necessary, by means of dilute acetic acid, Five C.C.of the formol reagent are added, and the mixture is heated in the boiling water-bath for about thirty minutes, until the albumin separates end the supernatant liquid becomes clear. The precipitate is collected on a tared filter and treated in the usual manner. J. F. B. New Reaction for Bile Acids and their Detection in Urine. A. Jolles. (Chem. Zeit., 1908, 21, 917.)--The author has discovered a new test for the bile acids which is superior to Pettenkofer’s reaction, and is not influenced by the presence of albumin, urea, carbohydrates, etc. Two to three C.C. of a 0.1 per cent. solution of the bile acid are treated with one or two drops of a 5 per cent. solution of rhamnose and 2 to 3 C.C. of strong hydrochloric acid, the mixture is boiled for a short time, and after the production of a transitory red coloration it ultimately acquires an intense green fluorescence. The reaction is due to the methylfurfural derived from the rhamnose, and is sufficiently sensitive to show the presence of 0.0001 gram of cholic acid in 1 C.C.of solution. For the detection of bile acids in urine, 50 C.C. of the urine are treated with 15 C.C. of a 3 per cent, casein solution, and 10 per cent. sulphuric acid is then added drop by drop until the casein is completely precipitated, for which purpose 0.6 to 0.8 C.C. is generally sufficient. The liquid is filtered off, and the precipitateTHE ANALYST. 432 is treated in a beaker with 10 C.C. of absolute alcohol, at the ordinary temperature for about an hour. The alcohoI is filtered off, 4 to 5 C.C.of the filtrate are mixed with one drop of a 5 per cent. solution of rhamnose and 4 to 5 C.C. of hydro- chloric acid, and boiled for a minute. After cooling, the contents of the tube are shaken with 2 C.C. of ether. In ordinary cases, the green fluorescence is then distinctly visible if the urine contains 0.05 per cent. of sodium taurocholate, but in the case of highly concentrated urines, and in urines rich in indican and aromatic hydroxy-acids, the reaction is less delicate, owing to the strong coloration of the filtrate. In these cases the fluorescence may be increased by concentrating the rays of light through a lens. J. F. B. Quantitative Estimation of Urea. A. Jolles. (Chem. Zeit., 1908, 21, 915.) -A new method for the estimation of urea is based on the determination of the carbonic acid produced by its oxidation by means of alkaline hypobromite. About 0.25 gram of urea is treated with 100 C.C. of a solution of 30 grams of bromine in 10 per cent. sodium hydroxide in a flask of about 750 C.C. capacity. The contents of the flask are protected from the air by a Bunsen valve, and are shaken for about five minutes to complete the oxidation. The excess of hypobromite is reduced by the addition of 3 grams of Devarda’s alloy. The carbonic acid is determined in the usual way, and the result is corrected by a blank experiment carried out with the omission of the urea. The errors of the method amount to 0.2 to 0.4 per cent. Unfortunately, the method is not applicable in presence of organic matters or carbonates. J. F. B.