This journal provides immediate access to some articles. Volume 35(2); February 1949 Bacteriology Effect of Visible Light on the Recovery of Streptomyces Griseus Conidia from Ultra-violet Irradiation Injury PMCID: PMC1062964 Biochemistry The Mode of Action of the Metal-Peptidases PMCID: PMC1062965 Chemistry Further Experiments with Vitamin A in Relation to Aging and to Length of Life PMCID: PMC1062966 Mathematics On Difference Sets PMCID: PMC1062967 Characters over Certain Types of Rings with Applications to the Theory of Equations in a Finite Field PMCID: PMC1062968 Bayes Solutions of Sequential Decision Problems PMCID: PMC1062969 Pathology Pharmacological Modification of Resistance to Radiation—A Preliminary-Report PMCID: PMC1062970 Physics Physical Systems of Curves in Space PMCID: PMC1062971 Zoology Conjugation Between Double Monsters and Single Animals in Paramecium Bursaria PMCID: PMC1062972 The Nature of the Specificity of Methyl Green for Chromatin PMCID: PMC1062973 Erratum Some Properties of Rotational Flow of a Perfect Gas PMCID: PMC1062974 Corrects: Some Properties of Rotational Flow of a Perfect Gas. Proc Natl Acad Sci U S A. 1948 March; 34(3): 119–124. Journal Matter Original table of contents page Administrative content — journal masthead, notices, indexes, etc. | ||