Neck tumors, or leukemia, developing in adult C3H mice following inoculation, in early infancy, with filtered (Berkefeld N), or centrifugated (144,000 ×g), Ak-leukemic extracts

Abstract

A found to be sufficiently small to pass through Seitz filters,* the results of preliminary filtration experiments previously reported were not entirely satisfactory, much of the agent being apparently absorbed by the asbestos pads used in the Seitz filters. For that reason, a series of experiments was carried out in which Berkefeld (N) candles, instead of the Seitz filters, were used for filtration. R/Ioreover, since it was recently observed that, following centrifugation at 7000xg, the leukemic extracts produced leukemia earlier than the 1400Xg supernate,3 the extracts were centrifugated at 7OOOxg prior to filtration in this study.