IWdl AGRICULTURAL CHEMISTRY — AGROTECHNY. 615 



yeast by the uddltion of a mixture of amino acids, but was improved by the 

 addition of small amounts of (lie antiiicuritic vitamin. 



Modificution of the Van Slyke iiu'tliod for determluing nrginiii, A. E. 

 KoKHi.KK (Jijur. Biol. Ctum., J,2 (VJ20), No. 2, pp. 267, 268, fig. i).— An appa- 

 ratus designed to eliminate bumpinj; in tlie ordinary determination of arginin 

 by tlie Van Slylce method is described and illustrated. 



A tube leading from the top of tlie reflux condenser connected with the diges- 

 tion flask extends nearly to tlie bottom of a wash bottle containing 30 cc. of n/1-1 

 acid. This bottle is connected by means of a long tube to a suction pump. Air, 

 l>uritied by passing through a wash bottle connected with tlie digestion llask, is 

 drawn slowly through the apparatus, carrying with it into the standard acid 

 the ammonia liberated duriiij:; the boiling. 



The graphical representation of analytical results, especially for the 

 analysis of flours, F. Maeion {Ann. Chim. Analyt., 2. ser., 2 {1920), No. 4< PP- 

 107-109, fig. 1). — The author suggests a graphical method of indicating the 

 quality of any particular flour from the results obtained in the customary 

 analytical determinations of moisture, dry gluten, hydrated gluten, fat, mineral 

 matter, and acidity. The results of these determinations are plotted on six 

 axes inter.secting at one point to form equal angles. The scale for each de- 

 termination is so chosen as to make with a flour of the first quality a regular 

 hexagon on the joining of the points representing the six determinations. In 

 any given flour a point lying within the regular hexagon indicates an inferiority 

 in that particular constituent, while every point situated outside the hexagon 

 is a sign of superior quality. 



How to know your flours, G. L. Teller {Amer. Food Jour., 15 {1920), No. 6, 

 pp. 7-9, 19). — This is a general discussion of methods for determining the qual- 

 ity, grade, and market value of flour. 



The keeping quality of milk as judged by the colorimetric H-ion deter- 

 mination, L. H. Cooi.EDGE ami K. W. Wyant {Jour. Dairy Sci., 3 {1920), No. 2, 

 pp. 156-166). — This is the detailed report, with experimental data, of the in- 

 vi'stigation leading to the development of the method previously noted (E. S. K., 

 1-. p. 613) for judging the keeping quality of milk by colorimetric H-ion deter- 

 mination. A provisional scheme is included for using the pH values in assign- 

 ing to any milk a score indicative of its suitablty either for market milk or for 

 manufacturing purposes. 



A method for manganese quantitation in biological material together 

 witli data on the manganese content of human blood and tissues, C. K. 

 Reiman and A. S. Minot {Jour. Biol. Chem., 42 {1920), No. 2, pp. 329-S45).— 

 The method described is essentially a modittcation of the method of Bertraud 

 previou.sly noted (E. S. R., 27, p. 670), the principal dilferences consisting in 

 ashing the material in quartz beakers instead of platinum and in taking up the 

 ash with an acid sulphate fusion instead of dissolving it in hydrochloric and 

 sulphuric acids at low temperatures. 



The technique of the procedure is described in detail, and results are given 

 of a .series of determinations of the manganese content of human blood and of 

 human tissues from a limited number of autopsies. 



The manganese content of tlie blood samples examined varied from 0.00-1 to 

 0.025 mg. per 100 gm. of blood, these results being considerably higher than those 

 reported by Bertrand. No abnormality in manganese content was shown in the 

 few pathological cases, including anemia, examined. Manganese was found in 

 all the tissues analyzed, the liver showing the largest amount, the average of 

 13 analy.ses being 0.17 mg. per 100 gm. of wet tissue. 



The determination of sugars by inversion, M. Hildt {Ann. Chim. .\nnliit., 

 t. ser., 2 {1920), No. 4, pp. 103-106). — This is a brief survey of the literature on 



