My question is about the classic study cited below (*) and available as a free pdf download from http://www.genetics.org/content/28/6/491.full.pdf+html At page 495 the authors use the "average division time" of bacteria dt, divided by ln(2), as the time unit in the equations (1) dN_t /dt = N_t , (2) N_t = N_o e^t. Can anyone tell me why this division by ln(2) was done? N_o is the original number of bacteria present. N_t is the number at time t. Obviously it has something to do with integration/differentiation, but I am missing the point. Thanks. *Luria, S. E.; Delbrück, M. (1943). "Mutations of Bacteria from Virus Sensitivity to Virus Resistance". Genetics 28 (6): 491–511.