Several types of deoxyribosyl compounds have been found in the acidsoluble fraction of normal and malignant tissues (l-8). In 1955 Potter and Schlesinger (1) reported the isolation of deoxynucleoside mono-, di-, and triphosphates from extracts of calf thymus. More recently LePage (7) reported the isolation of deoxyadenosine triphosphate from a tumor. Schneider (2), using a microbiological assay...