Hoffman, Heiner (New York University, New York, N.Y.), and Michael E. Frank. "Germination tube" growth in Escherichia coli microcultures. J. Bacteriol. 88:1151-1154. 1964.-Analysis of extensive time-lapse photomicrographic records of Escherichia coli microcultures uncovered two cases in which there occurred aberrant cell growth resembling a germination tube. Although previously observed by a number of investigators in gram-positive bacteria, the present observations appear to constitute the first time-lapse photomicrographic record concerning a gram-negative form. In the first case, with photographs taken at 15-sec intervals, the cell initially exhibited a clublike deformation, and the "germ tube" then issued from the club head. The "tube" had developed into a separate cell by the time the photographic record was concluded. In the second case, with the photographs taken at 1-min intervals over a longer period of time, the "germ tube" cell assumed a plastic dumbbell-like form after separation from its sister. It is suggested that the phenomenon results from a disturbance in cell-wall synthesis, while cytoplasmic growth continues unabated.