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In this paper certain aspects of the structure of chromatin are considered, with emphasis on the relationships of histone and residual protein to DNA. Recent findings relative to the complexing of histone with DNA are reviewed and material from this laboratory concerning the ratio of total histone to DNA and related topics are discussed. The questions of DNA strandedness and DNA repeating sequences are considered briefly. The relationship of residual protein of the cell nucleus to the structure of the chromosome is taken up and the bearing of the results of studies of nuclear gels on this problem are discussed. Recent results from this laboratory on the use of shear and a new autolytic procedure for detaching DNA from residual protein are outlined. The failure of residual protein to cause a marked elevation in the tm of nuclear DNA is discussed and material on the density gradient centrifugation of the DNA-residual protein complex is presented. Recent work on the fractionation of residual protein obtained from chromatin and isolated nuclei is critically reviewed. Finally a new hypothesis concerning a protein core structure in eukaryote chromosomes is presented briefly in the form of a model which may help to rationalize previously unexplained observations.