Abstract
The Feulgen absorbances of each of the two chromosome sets of anaphase and telophase nuclei were measured with the universal microspectrophotometer. Significant differences between the Feulgen absorbances of the daughter nuclei were found in 41.5 percent of nuclei from Ehrlich ascites tumor, in 16.7 percent from L1210 lymphoid leukemia, and in 18.7 percent from MC1M tumor. The possible significance of unequal nuclear division in producing aneuploidy was briefly discussed.