This journal provides immediate access to some articles. Volume 25(5); May 1939 Astronomy Influences of Limiting Magnitude upon Meteor Frequency PMCID: PMC1077757 Botany Cell Polarity and the Differentiation of Root Hairs PMCID: PMC1077759 Genetics The Time Factor in X-Ray Production of Chromosome Aberrations PMCID: PMC1077754 Induction of Triploidy and Haploidy in the Newt, Triturus Viridescens, by Cold Treatment of Unsegmented Eggs PMCID: PMC1077755 The Rôle of Developmental Rates in the Production of Notched Wing Characters in Drosophila Melanogaster PMCID: PMC1077756 Mathematics On Molecular and p-Adic Representations of Algebras PMCID: PMC1077760 Number of the Subgroups of Any Abelian Group PMCID: PMC1077761 The Transformation of a Lagrangian Series into a Newtonian Series PMCID: PMC1077762 Physiology and Biochemistry Is Auxin Produced in Roots? PMCID: PMC1077758 Journal Matter Administrative content — journal masthead, notices, indexes, etc. | ||