Abstract
Electron micrographs are presented of clumps of helical structures located in a region of the nucleus known to contain DNA. The filament making up the helix is about 70 A thick; it forms a coil with a diameter of 250-280 A and a distance between turns of about 140 A. The longest spirals are between 2500-3000 A in length and radiate from a diffuse central region.