This journal provides immediate access to some articles. Volume 7(1); January 1921 Anthropology Chronology of the San Juan Area PMCID: PMC1084724 Astronomy Internal Motion in the Spiral Nebula Messier 33: Preliminary Results PMCID: PMC1084720 Botany The Vascular Anatomy of Normal and Variant Seedlings of Phaseolus vulgaris PMCID: PMC1084727 Chemistry Experiments on the Electrical Conduction of a Hydrogen Alloy PMCID: PMC1084726 Geology Some Geologic Conclusions from Geodetic Data PMCID: PMC1084725 Physics The Attachment of Electrons to Neutral Molecules in Air PMCID: PMC1084721 On the Reflection and Re-emission of Electrons from Metal Surfaces: and a Method of Measuring the Ionizing Potential of Such Surfaces PMCID: PMC1084723 Physiology The Basal Metabolism of Girls 12 to 17 Years of Age PMCID: PMC1084722 Zoology The Present Status of the Long-Continued Pedigree Culture of Paramecium Aurelia at Yale University PMCID: PMC1084728 Journal Matter Original table of contents page Administrative content — journal masthead, notices, indexes, etc. | ||