LITERATURE 
(1) Burgess, P. S., 1922. The Reaction of Soils in the Field as Influenced 
by the Long-continued Use of Fertilizer Chemicals. Rhode Island 
Ag. Exp. Sta. Bui., 189 pp. 36. 
(2) Carr, R. H., and Brewer, P. H., 1923. Manganese, Aluminum and Iron 
Ratio as Related to Soil Toxicity. In Jour. Ind. and Eng. Chem., v. 
15, no. 6, p. 634-637, fig. 1. 
(3) Conner, S. D., 1921. Liming in Its Relation to Injurious Inorganic 
Compounds in the Soil. In Jour. Amer. Soc. Agron., v. 13, no. 3, p. 
113-124, fig. 1. 
(4) Conner, S. D. and Sears, O. H., 1922. Aluminum Salts and Acids at 
Varying Hydrogen-Ion Concentrations in Relation to Plant Growth 
in Water Cultures. In Soil Science, v. 13, no. 1, p. 23-41, figs. 9, pi. 4. 
(5) Fred, E. B., and Hart, E. B., 1915. The Comparative Effect of Phos¬ 
phates and Sulphates on Soil Bacteria. Agr. Expt. Sta. Univ. of 
Wisconsin. Research Bui.. 35, p. 35-66, figs. 6. 
(6) Hartwell, B. L., and Pember, F. R., 1918. The Presence of Aluminum 
as a Reason for the Difference in the Effect of So-called Acid Soil on 
Barley and Rye. In Soil Science, v. 6, no. 4, p. 259-278. 
(7) Hoffer, G. N., and Carr, R. H., 1923. Accumulation of Aluminum 
and Iron Compounds in Corn Plants and Its Probable Relation 
to Root-rots. In Jour. Agr. Res., v. 23, no. 10, p. 801-824, pi. 21. 
(8) Hoffer, G. N., and Trost, J. F., 1923. The Accumulation of Iron and 
Aluminum Compounds in Corn Plants and its Probable Relation to 
Root-rots II. In Jour. Amer. Soc. Agron. v. 15, no. 8, p. 323-331. 
(9) Hopkins, E. F., 1921. Growth and Germination of Gibberella Sau- 
binetii at Varying Hydrogen-ion Concentrations. Abstract in Phy¬ 
topath. v. 11, no. 1, p. 36. 
(10) Jones, L. H., and Shive, J. W., 1921. Effect of Ammonium Sulphate 
upon Plants in Nutrient Solutions Supplied with Ferric Phosphate 
and Ferrous Sulphate as Sources of Iron. In Jour. Agr. Res., v. 
21, no. 10, p. 701-728, fig. 9, pi. 136. 
(11) McCall, A. G., and Haag, J. R., 1921. The Relation of the Hydrogen- 
ion Concentration of Nutrient Solutions to Growth and Chlorosis of 
Wheat Plants. In Soil Science v. 12, p. 69-77, fig. 2. 
(12) Mirasol, J. J., 1920. Aluminum as a Factor in Soil Acidity. In Soil 
Science, v. 10, no. 3, p. 153-218, pi. 12. 
(13) Sherwin, M. E., Etheridge, R. B., and Dunham, A., 1922. A New Muck 
Soil Problem and Its Solution. In Jour. Amer. Soc. Agron., v. 14, 
no. 5, p. 212-215. 
(14) Willis, L. G., and Carrero, J. O., 1923. Influence of Some Nitrogenous 
Fertilizers on the Development of Chlorosis in Rice. In Jour. Agr. 
Res. v. 24, no. 7, p. 621-640. 
