This journal provides immediate access to some articles. Volume 43(2); February 15, 1957 Biochemistry THE METABOLISM OF L-THREONINE AND GLYCINE BY Escherichia coli PMCID: PMC528410 Botany STERILE INDUCTION OF CROWN-GALL TUMORS ON CARROT TISSUES IN VITRO PMCID: PMC528411 Chemistry THE STRUCTURE OF ALPHA KERATIN PMCID: PMC528412 THE STRUCTURE OF COLLAGEN PMCID: PMC528413 THE CONTRIBUTION OF THE α-HELICAL CONFIGURATION TO THE OPTICAL ROTATION OF POLYPEPTIDES AND PROTEINS PMCID: PMC528414 Genetics CONTRIBUTIONS TO THE THEORY OF THE CONTINUOUS BACTERIAL GROWTH APPARATUS: I. KINETICS OF GROWTH OF HOMOGENEOUS POPULATIONS PMCID: PMC528415 HETEROSIS AND ELIMINATION OF WEAK HOMOZYGOTES IN NATURAL POPULATIONS OF THREE RELATED SPECIES OF Drosophila PMCID: PMC528416 Mathematics REGULARITY THEOREMS FOR SOLUTIONS OF PARTIAL DIFFERENTIAL EQUATIONS WITH VARIABLE COEFFICIENTS PMCID: PMC528417 TWO RECURSIVELY ENUMERABLE SETS OF INCOMPARABLE DEGREES OF UNSOLVABILITY (SOLUTION OF POST'S PROBLEM, 1944) PMCID: PMC528418 A THEOREM ON STABILITY OF COMPLEX STRUCTURES PMCID: PMC528419 ON THE SPECTRAL SEQUENCE OF A FIBER SPACE. II PMCID: PMC528420 INTEGRATION OF A DIFFERENTIAL FORM ON AN ANALYTIC COMPLEX SUBVARIETY PMCID: PMC528421 APPLICATION OF HILBERT SPACE METHODS TO LIE GROUPS ACTING ON A DIFFERENTIABLE MANIFOLD PMCID: PMC528422 Erratum DIAPHANTINE EQUATIONS IN CERTAIN RINGS PMCID: PMC528423 Corrects: DIOPHANTINE EQUATIONS IN CERTAIN RINGS. Proc Natl Acad Sci U S A. 1956 September; 42(9): 656–665. Journal Matter Original table of contents page Administrative content — journal masthead, notices, indexes, etc. | ||