1917] AGRICULTURAL CHEMISTRY AGROTECHNY. 503 



Tartaric and a trace of citric acid were also determined in the aqueous and 

 alcoliolic extracts. 



Tlie cause of tlie ureolytic action of soy beans, D. H. Westice (Chem. 

 Weekbl, IS (1916), No. 24, pp. 663-677).— From tlie results of the study the 

 author concludes that the ureolytic action of soy beans is not due to bacterial 

 action. The activity of an aqueous glycerin extract was not hindered by anti- 

 septics, except mercuric chlorid and formaldehyde. An aqueous glycerin extract 

 easily passed through a Chamberland-Pasteur candle, the filtrate being prac- 

 tically inactive. This inactivity is not attributed to the removal of any micro- 

 organisms, but as probably due to the absorption of the colloidal enzymic mate- 

 rial as indicated by the complete loss of the ureolytic action of an extract by 

 treatment with kaolin. The action of sunlight on the extract retarded the 

 enzymic action considerably. Normally the action of the enzym was found to 

 be complete in eight hours at room temperature, in three hours at 30° C, and 

 in two hours at 50°. 



On account of the high fat content of the soy beans the author considers it 

 advantageous to remove the oil before preparing the aqueous glycerin extract, 

 as it facilitates later filtration of the extract. In the determination of urease 

 in urine the presence of glucose was found not to interfere up to concentrations 

 of 3 per cent. 



An aqueous glycerin extract of soy beans was found to be the most suitable 

 form in which to use the enzym, it retaining its activity for about three months. 

 The enzym in the bean, however, was found to be active after three years. 



See also previous notes by Groll (E. S. R., 35, p. 110) and Mom (E. S. R., 35, 

 p. 112). 



The separation of oxidase reactions from the catalase reaction, G. B. 

 Reed {Bot. Gaz., 62 (1916), No. 4, pp. S03-310 figs. 5).— Experiments are re- 

 ported in which platinized electrodes subjected to either nascent oxygen or 

 hydrogen, as previously described (E. S. R., 35, p. 713), were used. 



The results indicate that " factors which have no effect on the peroxidase 

 activity do alter the catalase action. In other words, the peroxidase action is 

 quite independent of the rate of hydrogen peroxid decomposition, and the two 

 reactions may be regarded as quite separate." 



Experiments showing that a similar separation of the oxidase from the cata- 

 lase may occur in the living cell are to be discussed in a subsequent paper. 



The relation of oxidase reactions to changes in hydrogen ion concentration, 

 G. B. Reed (Jour. Biol. Chem., 27 (1916), No. 2, pp. 299-302).— Experiments 

 are reported which indicate that 0.0005-0.007 molar hydrochloi'ic acid is suffi- 

 cient to prevent the action of certain oxidases. The optimum activity of the 

 oxidases appears to be reached when they are in a medium which is very nearly 

 neutral or slightly alkaline. 



Studies in the measurement of the electrical conductivity of solutions at 

 different frequencies. — V. Investigations on the use of the Vreeland oscillator 

 and other sources of current for conductivity measurements. VI. Investi- 

 gations on bridge methods, resistances, cells, capacities, inductances, phase 

 relations, precision of measurements, and a comparison of the resistances 

 obtained by the use of inductance and capacity bridges. VII. Investigations 

 on the true and apparent resistances, voltage, apparent capacity, size and 

 character of electrodes, ratio of inductance changes to resistance changes, 

 and the relation of induction and capacity to frequency, AV. A. Taylor and 

 S. F. Agree (Jour. Amer. Chem. Soc., 38 (1916), No. 11, pp. 2396-2430, figs. 19). 



The effect of pressure upon the potential of the hydrogen electrode, N. E. 

 LooMis and S. F. Agree (Jour. Amer. Chem. Soc., 38 (1916), No. 11, pp. 2391- 

 2396). 



