68 SOIL SCIENCE [BoT. Absts., Vol. VII, 



442. JoDiDi, S. L., S. C. MouLTON, and K. S. Markley. The mosaic disease of spinach 

 as characterized by its nitrogen constituents. Jour. Amer. Chem. Soc. 42: 1061-1070. 1920. — 

 The author jfinds that the lower nitrogen content of the diseased tissues may safely be con- 

 sidered as one of the striking characteristics of the mosaic disease of spinach. The leaves 

 of the normal plants have higher nitric-nitrogen content than the blighted spinach. The 

 difference in nitrate content of healthy and blighted root is slight. The higher ammonia 

 content and presence of nitrites may be said, also, to be characteristic of spinach blight. 

 The diseased plants were found capable of building up proteins. The leaves of the diseased 

 plants have a smaller proportion of acid amide, basic, and non-basic nitrogen, but a larger 

 proportion of peptide and protein nitrogen than the corresponding normal tissues. It is 

 because of these findings — together with the difference in total nitrate, nitrite, and ammoniacal 

 nitrogen content already reported — that we logically and forcibly come to the conclusion 

 that the pathological condition is brought about by the process of denitrification which 

 takes place in the spinach tissues. — J. M. Brannon. 



MISCELLANEOUS 



443. Galippe, V. Recherches sur la resistance des microzymas I. I'action du temps et 

 sur leur survivance dans I'ambre. [The longevity of microzymas and its survival in amber.] 

 Compt. Rend. Acad. Sci. Paris 170: 856-858. 1920.— See Bot. Absts. 7, Entry 391. 



444. Hamblin, C. O. To infect lucerne seed with nodule organisms. Agric. Gaz. New 

 South Wales 31: 466. 1920.— See Bot. Absts. 7, Entry 30. 



445. T., E. N, Botany at the British Association. Nature 104: 520-521. 1920. 



446. Thompson, Leonard R. Advantages of solid paraffin for sealing anaerobic fluid 

 cultures. Jour. Infect. Diseases 27 : 240-244. 1920. — A method is described for sealing tubes 

 with solid paraffin. A greater percentage of positive growths with stock anaerobic cultures 

 has been obtained than with parallel tubes sealed with liquid paraffin. — Selman A. Waksman. 



SOIL SCIENCE 



J. J. Skinner, Editor 

 F. M. ScHERTZ, Assistant Editor 



ACID SOILS 



447. Hartwell, Burt L., and F. R. Pember. The effect of dicalcium silicate on an acid 

 soil. Soil Sci. 10:57-60. 1920. — Pot experiments on an acid soil show that the beneficial 

 effect of "dicalcium silicate" on the growth of lettuce is due to its neutralizing effect. "Dical- 

 cium silicate" and "hydrated silica" do not appear to be of benefit because of their silicon 

 content. — W. J. Rabbins. 



448. Martin, W. H. The relation of sulfur to soil acidity and to the control of potato scab. 

 Soil Sci. 9:393-409. 1920. 



■ 449. MiRASOL, Jose Jison. Aluminum as a factor in soil acidity. Soil Sci. 10: 153-217. 

 12 pi. 1920. — Experiments were performed to determine the effect of aluminum salts alone 

 or in combination with calcium carbonate or with acid phosphate on the growth of sweet 

 clover in sand; the effect of limestone and acid phosphate on the acidity and productivity 

 of soil ; the effect of the removal of some aluminum from the soil on the growth of sweet clover 

 and whether iron and manganese are factors in the acidity of the soils investigated. Alumi- 

 num salts were highly toxic to sweet clover when applied in amounts chemically equivalent 

 to the acidity of the soil and fatal in amounts five times the acidity of the soil. Calcium 

 carbonate or acid phosphate decreased or eliminated the toxicity of aluminum salts. Alu- 

 minum hydroxide was not toxic. Both limestone and acid phosphate reduced the acidity of 



