The existence of dinucleosomes, or elementary supranucleosomal structures of chromatin, was discovered by the writers with the use of an endonuclease from B~evibacterium ammoniagenes [i]. The endonuclease produces cleavage of rat liver chromatin DNA by single-stranded breaks in each second linker, and this leads to a decrease in the effectiveness of action of endogenous nuclear nucleases [i, 3]. Meanwhile, other investigators demonstrated the dinucleosomal organization of chromatin from sea urchin sperm , rat liver , and chick erythrocytes [7, i0]. Unmodified [6~ i0] or ferritin-bound pancreatic DNase I  was used as the probe. in all the investigations cited above exogenous endonucleases were used. Endogenous enzymes under these circumstances either were inhibited [7, 8], their effect weakened by the use of short-term hydrolysis by high concentrations of exogenous nuclease , or tissues in which endogenous activity was absent were used [4, 7, 8, i0].