1916] AGRICULTURAL CHEMISTRY — AGROTECHITY. 315 



aration of the reagent used in this method is very important, particularly the 

 preparation of the glue solution. The presence of hydrochloric acid, large 

 amounts of iron, and, especially, organic substances influence the correctness 

 of the titration. The water-soluble phosphoric acid in superphosphates and 

 that obtained from Thomas slag by digestion with sulphuric acid can be deter- 

 mined directly after neutralizing the solution. The procedure is applicable to 

 routine analyses, but is not recommended on account of the care and patience 

 required in its manipulation. The accuracy of the method is indicated by sub- 

 mitted experimental data. 



The volumetric determination of potassium and its application in the 

 analysis of fertilizers, G. Ajon {Ann. R. Staz. Sper. Agriim. e Frutticol. Acireale, 

 3 (1915), pp. 91-104). — The procedure described by the author is as follows: 



About 25 cc. of a 2 per cent solution of potassium chlorid or potassium sul- 

 phate, or an amount equivalent to from 1.08 to 1.26 per cent of potassium oxid, 

 is transferred to a 150-200 cc. Erlenmeyer flask, 50 cc. twice-normal tartaric 

 acid added, and the mixture thoroughly shaken. Twenty-five cc. of half-normal 

 sodium hydroxid is then added and the mixture again strongly agitated for 

 five minutes. To this 25 cc. of 96 per cent alcohol are added and the flask and 

 contents allowed to stand for from sis to eight hours. The precipitate thus 

 formed is washed by decantation several times and finally transferred to the 

 filter, where it is thoroughly washed with neutral 9G per cent alcohol. It is 

 then treated with tenth-normal alcoholic sodium hydroxid until strongly alka- 

 line to phenolphthalein, and allowed to set for about five minutes with occa- 

 sional shaking. When the precipitate is completely dissolved the amount of 

 tenth-normal hydroxid used is determined by titration with standard hydro- 

 chloric acid. 



The number of cubic centimeters of tenth-normal sodium hydroxid used to 

 dissolve the bitartrate, multiplied by 0.00471, gives the amount of K2O present 

 in the original solution. Analytical data submitted indicate the accuracy of 

 the method. 



The use of enzyms and special yeasts in carbohydrate analysis, W. A. 

 Davis {Internal. Sugar Jour., IS {1916), No. 208, pp. 166-171).— This material 

 has been previously noted from another source (E. S. R., 35, p. 206). 



The possibility of titrating the monosubstituted amino group of amino 

 acids with formol, A. Clementi {Atti R. Acad. Lincei, Rend. CI. Sci.. Fis., Mat. e 

 Nat., 5. ser., 24 {1915), I, No. 4, pp. 852-359; Arch. Farmacol. Sper. e Sci. Aff., 

 21 {1916), No. 6, pp. 215-224; «6s. in Cliem. Ahs., 9 {1915), No 11, p. 2394).— 

 The Sorensen formol titration method for the determination of the quantity 

 of amino gi-oups in amino acids has not as yet been applied to amino acids in 

 which the amino group is partly or completely substituted. The author has 

 performed experiments of this kind with sarcosin, and shows that the amino 

 group, even if monosubstituted, reacts with formaldehyde. In titrating mono- 

 substituted amino acids according to Sorensen's method it is, however, necessary 

 to titrate to the intense coloration of phenolphthalein, as otherwise the results 

 will be slightly too low. 



Concerning the protein content of meat, N. W. Jannet (Proc. Soc. Expt. 

 Biol, and Med., IS {1916), No. 5, pp. 83, 84). — The author indicates the error 

 inherent in the protein determinations in meat because of the large amount of 

 nonprotein nitrogen present. The average nitrogen content of meat proteins lies 

 between 16.2 and 16.7 per cent, and is not 16 as the factor 6.25 commonly used 

 indicates. The principle involved in a modified procedure for the direct deter- 

 mination of the proteins in muscle is the coagulation of the muscle in alcohol 

 and the removal of nonprotein material by extraction. With proper precau- 



