Abstract
The higher order structure of chromosomes of Raji cells has been investigated with a field emission type scanning electron microscope after the chromosomes had undergone surface-spreading. Metaphase chromosomes were seen as a mass of fibers about 336±42 Å in mean diameter with a range of 226 Å to 429 Å. Chromosome fibers had twisted loops with nodules. The organization of the fibers in the construction of the metaphase chromosomes was neither regular nor periodic. The kinetochore region was discernible as a clear constriction, but it had no characteristic structure except for several chromosome fibers parallel to the axis of the chromatids.
