A blaze-dry spreading procedure for the electron microscopy of chromosomes from acid alcohol-fixed human lymphocytes

A procedure is described for the blaze-drying of human lymphocyte chromosomes on carbonized Parlodion film. Films are prepared by applying Parlodion solution to sheets of freshly cleaved mica. Damage to the film during blaze-drying is prevented by chilling the mica sheets on dry ice before flaming. After spreading, the film and metaphases are floated free from the mica and transferred to a slide of Formav-coated electron microscope grids. The resulting preparations yield complete metaphase spreads and banded chromosomes morphologically similar to those observed with the light microscope.