84 Biological Scction, American Chemical Society [Oct. 



Merck's blood charcoal. No sugar is lost by this procedura. I£ the 

 urine is diluted to only 7/5 original volume, the filtrate is water-clear 

 for polarization. Of the filtrate, 5 c.c. are transferred to a 100 c.c. 

 Kjeldahl flask, neutralized with a saturated Solution of sodium car- 

 bonate, using alizarine as the indicator, and 5 c.c. of a modified 

 Benedict reagent are added. After placing a pebble in the liquid 

 and fixing the flask in an inclined position directly over a small Bun- 

 sen flame, the whole is boiled for 2^ minutes. The resulting 

 small volume is transferred to a centrifuge tube and made up to 10 

 c.c. Examined under a shaded electric light and against a dark 

 background, even a trace of glucose shows turbidity and after centri- 

 fugation as little as 0.0035 percent shows a film of red precipitate. 

 Quantitative estimations are made by comparison with Standards 

 based upon a normal urine excreted on a normal diet and showing 

 zero rotation (or nearly so) after clarification, and to which glucose 

 is added in amounts that increase the content by successive incre- 

 ments of 0.0 1 percent. The sensitiveness is so great that such 

 slight differences in proportion may easily be detected. 



Composition of the modified Benedict reagent : sodium citrate, 

 100 gm.; sodium acetate, 100 gm.; sodium carbonate (anhyd.), 50 

 gm.; cryst. copper sulfate (Kahl.), 12.5 gm,; water (dist.), 

 500 c.c. 



The estimation of protein and amino- and nucleic-acids in 

 potable waters. Philip A. Kober. (Harriman Research Laho- 

 ratory, Roosevelt Hospital, Nezv York.) Experiments show that 

 by using the right precipitants and evaporating to one-tenth of the 

 original volume, proteins and nucleic acids can be estimated in pot- 

 able waters by the author's nephelometric method. This method 

 will easily reveal the presence of one part of substance in one 

 million parts of water. By using the copper method,^ potable 

 waters may be analyzed for amino-acid nitrogen before or after 

 hydrolysis. This method will reveal one part of amino-acid nitro- 

 gen in one million of water, without difficulty. 



The fate of protein digestion products in the body. Donald 

 D. Van Slyke and Gustave M. Meyer. (Rockefeller Institute 

 for Medical Research, New York.) Previous work by the authors 



3 Kober: Jour. Amer. Chem. Soc, 1913, xxxv, p. 1546. 



