The method has remarkable specificity for nuclear substance and nuclear detail is readily and clearly visualized. The remainder of the cell remains unstained. The method requires acid hydrolysis, as with the Feulgen reaction, after which the cells are mordanted in 1-2% formaldelhyde and stained with 0.25% basic fuchsin, in N/25 HC1. Yeast cells are handled in test tubes, while the mycelial phase is grown on cellophane spread over the agar, then manipulated through the staining procedure in petri dishes.