This journal provides immediate access to some articles. Volume 26(1); January 15, 1940 Anthropology and Psychology “Personality” Differences as Described by Invariant Properties of Individuals in Interaction PMCID: PMC1077997 Astronomy Galactic and Extragalactic Studies: III. Photographs of Thirty Southern Nebulae and Clusters PMCID: PMC1078002 On the Determination of the Orbital Elements of Eccentric Eclipsing Binaries PMCID: PMC1078003 Galactic and Extragalactic Studies: IV. Photometry of Two Large Southern Clusters of Galaxies PMCID: PMC1078004 The Doppler Effect in Resonance Lines PMCID: PMC1078005 Botany The Nature of Absorption of Radioactive Isotopes by Living Tissues as Illustrated by Experiments with Barley Plants PMCID: PMC1077998 Genetics Analysis of Variance Applied to Human Genetics PMCID: PMC1077994 Two X-Ray Induced Mosaics in Drosophila Pseudoöbscura PMCID: PMC1077995 The Size of the Tobacco Mosaic Particle from X-Ray Determinations PMCID: PMC1077996 Mathematics Concerning the Open Subsets of a Plane Continuum PMCID: PMC1077999 On Homotopy and Extension of Mappings PMCID: PMC1078000 Integration and Differentiation in Partially Ordered Spaces PMCID: PMC1078001 Physiology and Biochemistry The Theory of the Visual Threshold: I. Time and Intensity PMCID: PMC1078006 Temperature and the Critical Intensity for Response to Visual Flicker: IV. On the Invariance of Critical Thermal Increments, and the Theory of the Response Contour PMCID: PMC1078007 On Spinal Shock PMCID: PMC1078008 Zoölogy and Anatomy Physiology of Development of the Feather: IV. The Diurnal Curve of Growth in Brown Leghorn Fowl PMCID: PMC1078009 The Pigment-Forming Potency of Early Chick Blastoderms PMCID: PMC1078010 Journal Matter Original table of contents page Administrative content — journal masthead, notices, indexes, etc. | ||