p501fig13.26 A simple differential equation describes the processes of transmitter accumulation and release that do their best, at a finite rate, to carry out unbiased transduction.<BR>||  Transmitter accumulation and release.  Transmitter y cannot be restored at an infinite rate: T = S*ym y ~= B,  Differential equations: d[dt: y] = A*(B - y) - S*y = accumulate - release.  Transmitter y tries to recover to ensure unbiased transduction.  What if it falls behind?  Evolution has exploited the good properties that happen then.