Formaldehyde-Induced Fluorescence of Intranuclear Bodies in Melanoma Cells*

SUMMARY.— Imprints of 5 human melanomas were treated with formaldehyde and studied by fluorescence microscopy. Granular fluorescence was seen in the cytoplasm, and, in two of the melanomas, also large intranuclear fluorescent bodies. Microspectrofluorometry showed that the fluorescence of the nuclear bodies and the cytoplasm had the same excitation and emission maxima. Intranuclear bodies were also demonstrated in imprints stained with May‐Grünwald‐Giemsa.