This journal provides immediate access to some articles. Volume 25(3); March 1939 Astronomy A Determination of the Distance to the Galactic Center PMCID: PMC1077724 Supernovae and Stellar Collisions PMCID: PMC1077725 Botany Embryo-Sac Development in Plumbagella PMCID: PMC1077729 Genetics On the Subdivision of the Genus Drosophila PMCID: PMC1077728 Mathematics The Convex Cells Formed by Seven Planes PMCID: PMC1077731 On the Existence of Minimal Surfaces of General Critical Types PMCID: PMC1077732 Additive Set Functions on Groups PMCID: PMC1077733 Physiology and Biochemistry The Distribution of Intermedin in the Pars Anterior of the Chicken Pituitary PMCID: PMC1077730 Psychology and Anthropology Reliability of Measurements of the Steady Polarity Potential of the Eye PMCID: PMC1077727 Zoölogy and Anatomy Observations on Chromosome Elimination in the Germ Cells of Sciara Ocellaris PMCID: PMC1077726 Journal Matter Administrative content — journal masthead, notices, indexes, etc. | ||