Synchronization of rabbit bone-marrow cells in vivo.

The recovery of the rabbit bone-marrow from anaemia was investigated during an eight-day period of daily punctures of the tibiae after six days of phenylhydrazine treatment. A maximum of erythroid (range, 37.1 to 44.0%) and a minimum of leukoid cells (range, 8.4 to 13.4%) was observed on the fifth day of recovery. The rest, about 50% cells were reticulum cells. Signs of recovery were observed in peripheral blood as soon as on the first day after phenylhydrazine treatment. This led to the assumption that the tibiae became repopulated with active erythropoietic cells during anaemia, and that the reticulum cells might play a role as erythroid precursors in this process.