This journal provides immediate access to some articles. Volume 21(4); April 1935 Botany New Varieties of Western Willows PMCID: PMC1076561 Chemistry The Oxygen Equilibrium of Hemoglobin and Its Structural Interpretation PMCID: PMC1076562 The Rate and Extent of Anaerobic Decomposition of Sulfite Waste Liquor by Bacteria of Sea Bottom Mud: II. Bacteriological PMCID: PMC1076563 Genetics Identification of the Salivary Gland Chromosomes in Drosophila Pseudoobscura PMCID: PMC1076564 The Behavior of Unstable Genic Loci—An Hypothesis PMCID: PMC1076565 Pollen-Tube Growth of a Translocation of the 1·2 Chromosome in Datura PMCID: PMC1076566 Geology and Paleontology Insectivora from the Sespe Uppermost Eocene, California PMCID: PMC1076567 Mathematics Application of Chain-Deformations to Critical Points and Extremals PMCID: PMC1076568 Note on Pontrjagin's Topological Theorem of Duality PMCID: PMC1076569 Connections between Differential Geometry and Topology PMCID: PMC1076570 Physiology and Biochemistry The Sensitive-Volume of the Meiotic Chromonemata of Gasteria as Determined by Irradiation with X-Rays PMCID: PMC1076571 Zoölogy and Anatomy Movement of Sensory Hairs in the Ear PMCID: PMC1076572 Journal Matter Administrative content — journal masthead, notices, indexes, etc. | ||