428 SOIL SCIENCE [Bot. Absts. 



one outstanding exception in B. arsenreducens, and other resistant members probably exist. 

 Although over a dozen arsenic resistant species of bacteria were examined, only two showed 

 any chemical activity towards arsenic; the earlier described B. arsenoxydans, which oxidizes 

 arsenite to arsenate, and B. arsenreducens, which reduces arsenate to arsenite. The others 

 were merely tolerant. In arsenical dipping tanks an automatic enriching of resistant faecal 

 bacteria and suppression of sensitive forms takes place. — E. M. Doidge. 



ELECTRICITY AND MECHANICAL AGENTS 



2915. Lee, S. C. Electrical treatment of seed. Agric. Gaz. Canada 6: 173-175.1919. 



MISCELLANEOUS 



2916. Haines, F. M. A new auxanometer. Ann. Botany 33 : 181-188. 1919. — A fiber at- 

 tached to the tip of the plant passes over a vertical support to a differential pulley wheel 

 permitting magnification up to 100, and a connected fiber guides a pen carried on a hori- 

 zontal trolley along a clock-driven drum. Thus far there is no great deviation in principle 

 from some previous instruments, but a distinctive new feature is found in a device for com- 

 pensating hygroscopic or other changes in length of the fibers used. It depends on the 

 adjustment of three threads over balanced pulley wheels in such manner that the lengthen- 

 ing of any one is balanced by shortening of another, the details, somewhat complicated and 

 involving use of weights, being not explainable without a diagram. The account is prelimi- 

 nary and not accompanied by test records, which will be awaited with interest in view of the 

 many parts, including 8 pulleys and wheels, involved. — W. F. Ganong. 



2917. Metge, G. [Rev. of: Wagner, P. Wie wirkt die Saatgutbeschaffenheit auf den 

 Kartoffelertrag unter dem Einfluss verschiedener Pflanzweite, Dungung und Jahreswitterung. 

 (Influence of the seed stock on the yield of potatoes under the influence of different distances 

 of planting, manuring and weather.) Deutsch. Landw. Presse 45: 169, 175-176, 183. 1918. J 

 Biedermann's Zentralbl. Agrikulturchem. 47: 325-333. 1918— See Bot. Absts. 3, Entry 1386. 



2918. Neger, F. W. Die Blattrollkrankheit der Kartoffel. [The leafroll disease of the 

 potato.] Zeitschr. Pflanzenkrankh. 29:27-48. 7 fig. 1919.— See Bot. Absts. 3, Entry 2712.] 



2919. Schoevers, T. A. C. Het krullen van tomatenbladeren. [The rolling of tomato 

 leaves.] Tidschr. Plantenz. 25 (Bijblad) : 11-12. 1919.— See Bot. Absts. 3, Entry 1659. 



SOIL SCIENCE 



J. J. Skinner, Editor 



ACIDITY AND LIMING 



2920. Anonymous. [Rev. of: Hoagland, D. R., and L. T. Sharp. Relation of carbon 

 dioxide to soil reaction as measured by the hydrogen electrode. Jour. Agric. Res. 12 : 139-148 

 1918.] Jour. Ecol. 7:95. 1919. 



2921. Anonymous. [Rev. of: Hutchinson, R. H. Soil acidity as influenced by green, 

 manures. Jour. Agric. Res. 13: 171-197.] Jour. Ecol. 7: 93-94. 1919. 



2922. Hartwell, Burt L., F. R. Pember, and L. P. Howard. Lime requirements as 

 determined by the plant and by the chemist. Soil Sci. 7: 279-282. 1919. — Determinations of 

 the lime requirement of soil from limed and unlimed ammonium sulfate fertilized plots and 

 limed and unlimed sodium nitrate fertilized plots showed all samples to have a considerable 

 lime requirement. Pot experiments with beets and lettuce in the above soils treated with 

 varying amounts of freshly hydrated calcium oxide showed that the maximum crop was 

 obtained while the soil still showed a lime requirement of 5000 pounds as shown by analysis 

 after crop growth. — William J. Robbins. 



