Because, by the second day of incubation, any cells that have undergone reversion mutations give rise to revertant colonies, like rats leaving a ship.
Af ūví ađ ä öđrum degi útungunarinnar munu allar frumur sem gengist hafa undir erfđabreytinguna flũja sína fyrri eiginleika eins og rottur yfirgefa sökkvandi skip.