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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1911 Excerpt:... Urea.--Hypobromite Method.--The procedures of physiologic chemistry-give the only accurate methods for the estimation of urea, the chief nitrogenous excrementitious product in the urine. The total nitrogen content should be determined by the Kjeldahl method, and this may be expressed as urea. Such a procedure, however, is too complicated for clinical work, and we are obliged to use a less accurate method for such a determination. It must be remembered, however, that the determination of urea by any method is of no value unless a portion of.a twenty-four-hour specimen of urine is used. The Hypobromite Method.--The hypobromite method is the most convenient for clinical work; but it has been shown by Ryan and Marshall that an average of 92.56 per cent, of the nitrogen of urea is liberated as free nitrogen gas in the tube. The Doremus-Hinds ureometer is the instrument most used in this method. The vertical tube and bulb are filled with a solution of sodium hypobromite made by dissolving 100 grams of sodium hydroxid in 250 cubic centimeters of water and adding 25 cubic centimeters of bromid. The side arm of the tube is then filled with urine to the one cubic centimeter mark, after opening the stopcock sufficiently to allow the reagent to fill its lumen. The stopcock is now opened wide and the one cubic centimeter of urine is allowed to mix with the reagent. The reaction liberates nitrogen gas, which collects I Fig. 218.--Hinds' ModificaTion OF THE DOBEMUB Uheometer. in the vertical tube, and after the bubbles have subsided the volume is read off. The graduations represent grams of urea per cubic centimeter of urine. This figure multiplied by the number of cubic centimeters in the twenty-four-hour specimen will give the amount of urea eliminated during the day....