This journal provides immediate access to some articles. Volume 37(2); February 1951 Biochemistry The Mechanism of Rhodopsin Synthesis PMCID: PMC1063306 Genetics Polyploidy in Yeast and its Bearing on the Occurrence of Irregular Genetic Ratios PMCID: PMC1063307 Mathematics On the Functional Equations of the Dirichlet Series Derived from Siegel Modular Forms PMCID: PMC1063308 The Structure of Alternative Division Rings PMCID: PMC1063309 Hausdorff Measure and Lebesgue Area PMCID: PMC1063310 On the Structure of Extremal Polynomials PMCID: PMC1063311 On the Boundary Behavior of Minimal Surfaces PMCID: PMC1063312 The Connectedness of the Orthogonal Group in Hilbert Space PMCID: PMC1063313 A Class of Soluble Diophantine Equations PMCID: PMC1063314 Physics The Determination of Crystal Structures from X-Ray Data Without a Knowledge of the Phases of the Fourier Coefficients PMCID: PMC1063315 Psychology Prior Learning as a Factor in Shaping Performance Curves PMCID: PMC1063316 Journal Matter Original table of contents page Administrative content — journal masthead, notices, indexes, etc. | ||