Cytological evidence that both RNA and DNA may form a complex with the same protein.

Deoxyribonucleic acid can be added back to protein sites from which the original nucleic acid, ribo- or deoxyribo-, is removed. If sections of frozen-substituted ovarian follicle cells of a leafhopper are first extracted by hot trichloracetic acid to remove nucleic acids and then immersed in a solution of a commerical preparation of deoxyribonucleic acid, the nucleic acid becomes attached to nuclear and cytoplasmic sites and can be rendered visible by the Feulgen reaction. The addition occurs in certain other tissues as well. The results are discussed in relation to biochemical and other cytochemical investigations of the nucleoprotein complex.