So we pulse-labeled glucose-grown E.coli B/r,collected
newborn cells eluted from the membrane for about three generations,and measured radioactivity per cell.The results were very clear.The radioactivity per cell decreased in a step-wise pattern, with horizontal plateaus followed by sudden two-fold decreases every generation.As I remember,we concluded that the two-fold reduction in radioactivity per cell each generation was the relatively uninteresting consequence of semiconservative replication followed by random distribution of chromosomal DNA into daughter cells,and that we had learned little of real value.What a mistake.The mistake was probably a consequence of our inability at that time to accurately measure,and thus interpret, the characteristic fluctuation in concentration of newborn cells eluted from a surface-bound population.Unfortunately it would take me two
more years to think about this experiment again and interpret it correctly.