Hoffman, Heiner (New York University, New York, N.Y.), and Michael E. Frank. Time-lapse photomicrography of cell growth and division in Escherichia coli. J. Bacteriol. 89:212-216. 1965.-Photomicrographs at 15-sec intervals of cells growing at 37 C disclosed that in a cell with a generation time of 21.0 min the processes of furrowing, cross-wall formation, and cell separation are completed within 2.5 min after the division furrow first becomes clearly visible. Among a large number of cultivations examined, only a few cells late in one microculture at 43.5 C failed to separate once the cross wall was completed. Measurements of cell lengths during a 5-min period, extending from just before to just after division, showed that elongation of the cell is a discontinuous process, although the growth rate over the 5-min period is exponential. At the time of cell division, it appears that the synthesis of cell-wall material is diverted entirely into formation of the cross wall.