This report presents an attempt to assess some of the problems connected with the use of radiophosphorus as an indicator of bone vascularity. From this account of our experiences with the uptake of radio-phosphorus by rabbit bones, some of the factors emerge which may be causing the observed wide variations in the activity of similar areas in different animals.
Previous attempts have been made to determine the viability of bone by using its ability to take up P32 from the blood stream as an index (Tucker, 1950).
The notation by Neuman and other workers that the early rapid stage of P32 uptake by bone was not a vital process, but, rather, was a purely physicochemical adsorption onto crystal surfaces, has tended to discredit this approach. Tucker found that the ratio of normal bone activity to femoral head activity had to rise to a high value before the femoral