For the purpose to reveal the relation between cell death and nuclear stainability by supravital staining with basic dyes observations have been made on the cells of bone marrow, peripheral blood and lymph node from anemic and non-anemic rabbit, rat, mouse and chicken, and thymus
from young mouse. The cells were stained supravitally in blood serum, isotonic saline, calcium chloride and sucrose solutions with the dyes; brilliant cresyl blue (B. C. B), Nile blue (N. B.), neutral red (N. R.), Janus green (J.G.) and eosin (E.). The following results were obtained: 1. In the presence of blood serum all the living cell nuclei observed were not stained supravitally, except some mature erythroblasts and nucleated red cells. 2. In isotonic saline, CaCl2 and MgCl2 solutions all the erythroid
cell nuclei were stained deep by B. C. B., N. B., N. R., slightly by J. G. but not by E. In stainability the younger the cell is the deeper in its nuclear staining. The nuclei of other cell strains were not stained. 3. In isotonic sucrose the nuclei of mature granulocyte were also
stained by B. C. B. and N. B. but not by other dyes. The nuclei of lymphoid cells and myeloid cells appeared pale without being stained by any dyes. The nuclei of erythroblasts in sucrose solution were stained deeper
with B. C. B. and N. B. than those in isotonic saline.
The differences between supravital stainability of the nuclei among the cells belonging to different strain and among those of the same strain but in different maturation stage and the nuclear staining after cell death have been discussed from the possible dissociation of DNA from histone.</p
