614 EXPERIMENT STATION RECORD. [Vol. 37 



phosphate. When, in similar experiments, enzym concentration is varied within 

 limits suitable for such quantitative study, the rate of maltose formation is 

 found to be directly proportional to the enzym concentration Hp to a yield of 

 about half the theoretical amount of maltose. This broadens the range within 

 which diastatic activities may be compared quantitatively." 



No " region of linear relationship " in which the yield of reducing sugar is 

 directly proportional to the time was found. No cessation of hydrolysis nor 

 true equilibrium at 80 per cent was shown in experiments with widely varied 

 enzym concentration, as was claimed by some previous Investigators. 



A noteworthy effect of bromids upon the action of malt amylase, A. W. 

 Thomas (Jour. Amer. Chem. Soc, 39 (1917), No. 7, pp. 1501-1503, fig. 1).— In 

 an investigation on the activation of malt amylase by acids and salts it was 

 observed that bromids when present in small amounts exercised an inhibitory 

 effect on the action, but an activating action was observed when the concentra- 

 tion of the salt was increased. As previously shown, the chlorid, nitrate, sul- 

 phate, and phosphate of sodium and potassium activated malt amylase propor- 

 tionately to the concentration of the salt present. The experiments were re- 

 peated with sodium and potassium bromid which had been recrystallized several 

 times, positive results being obtained. 



Experimental data are submitted in tabular and graphical form. 



A handbook of organic analysis, H. T. Clarke (London: Edxoard Arnold, 

 1916, 2. ed., pp. VIII +26S, figs. 25).— The subject is treated under the topics of 

 preliminary investigation, examination for radicles, separation of organic com- 

 pounds, quantitative determination of constituent elements, quantitative deter- 

 mination of radicles, and determination of some physical proi>erties. 



Classified tables which give the melting or boiling points and common reactions 

 of the more common organic compounds are included. A detailed index of the 

 tables is appended. 



A titration flask, F. K. BEzzENBEBQEai (Jour. Amcr. Chem. Soc, S9 (1917), 

 No. 7, p. 1S21, fig. 1). — A titrating flask, to be used in place of the weighing 

 burette, which has been found to posse.ss some advantages in volumetric analyses 

 is described. 



The estimation of sulphur in plant material and soil, G. A. Olson (Wash- 

 ington Sta. Bui. 145 (1917), pp. S-12, figs. 2). — Tabular analytical data relative 

 to the sulphur content of linseed meal, corn, peas, beans, wheat, casein, and 

 gluten obtained by the Parr bomb calorimeter method and comparetl with 

 the official and Osborne methods show that with certain precautions tlie bomb 

 method can be successfully used without sacrificing any degree of accuracy for 

 speed. The material should be very finely ground, the silica removed, and the 

 precipitate of barium sulphate well washed. 



For the determination of sulphur in plant materials a charge of 0.G87 gm. 

 was found to be the most satisfactory. The fusion mixture used was the same 

 as that recommended by Parr, except that sodium nitrate was substitute<l for 

 potassium nitrate because of the tendency of potassium salts to form double 

 salts with barium. The mixture consisted of boric acid 5, sodium nitrate 3, 

 and magnesium metal 1 parts by weight. The exact amount of sodiiun peroxid 

 necessary was found to vary with the nature of the material, approxiniutoly 

 16 gm. being necessary for gluten and similar nitrogenous substances, ^vhile for 

 starchy substances, such as flour, etc., from 12 to 14 gm. was found sufllcient. 

 Shortening of the electrodes about | in. in the Parr bomb apparatus was found 

 to be more satisfactory with the quantity of material used in the charges. A 

 bomb having a bottom cast In one piece with the shell is considered preferable 

 to one with a removable bottom. 



