Ingraham (See B. A. 8(9): Entry 20525) reported that crystal violet prolongs lag, but does not influence growth rate during the logarithmic phase. She also finds that the time required to reach visible turbidity is a linear function of the logarithm of N i, the bacterial count at inoculation. If these observations are correct, it necessarily follows that T l, length of lag period, is a similar function, and may be expressed by: T l C 1[long dash]K 2 log N i, where C 1 and K 2 are constants, and K 2 is a function of concentration of dye.