This journal provides immediate access to some articles. Volume 12(9); September 1926 Mathematics Postulates in the History of Scienec PMCID: PMC1084680 On the Zeros of Functions Associated with a Linear System of the Second Order PMCID: PMC1084681 Concerning Irreducibly Connected Sets and Irreducible Continua PMCID: PMC1084682 Physics Interpretation of Deviations from Ohm's Law PMCID: PMC1084683 Rubidium and Caesium-Like Doublets of Stripped Atoms PMCID: PMC1084684 The Fine Structure of Certain Lines and Energy Levels of Cadmium PMCID: PMC1084685 On the Spectrum of Argon PMCID: PMC1084686 Ionization in Reacting Gases PMCID: PMC1084687 Zoölogy Localization of Formative Agencies in Hydra PMCID: PMC1084688 Inhibition of Regeneration in Two-Headed or Two-Tailed Planarians PMCID: PMC1084689 Inhibition of Regeneration in Planarians by Grafting: Technique of Grafting PMCID: PMC1084690 Journal Matter Original table of contents page Administrative content — journal masthead, notices, indexes, etc. | ||