摘要：

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. Three preparations of the sodium salt of desoxyribonucleic acid were isolated from calf thymus by a method expected to give minimal or no depolymerization. In addition, preparations were made from calf spleen and bull testis tissues. Streaming birefringence measurements indicate that the distributions of molecular length are identical in the calf thymus preparations. The apparent molecular lengths range from 7,500 to 11,500[...]. The sodium desoxyribonucleate from testis appeared to be significantly shorter; that from spleen was intermediate between thymus and testis. The distributions of molecular length of two calf thymus preparations isolated by N. Simmons were compared with those prepared here. Several explanations are put forth to explain the polydispersity and discrepancies between preparations.

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