Sex Chromatin Mass in Living, Cultivated Human Cells

Abstract

Cells taken from human skin were observed with a phase contrast microscope before and after Feulgen staining. Living cells with the sex chromosome karyotypes XX and XXY (but not XO or XY) manifested, in late interphase, an object that corresponded in number, location, and shape to the sex chromatin mass found in the same cells after staining.