Somewhere on the web there's an article from a very old publication--I'm thinking of around 1880, where someone using a microscope supposedly established that given long enough an edge that had been slightly shredded by shaving would "grow" and straighten itself out over the course of a couple of weeks. It's one of those articles that smells heavily of primitive non-science reinforced by lots of science talk. That is, I'm guessing, the origin of this particular myth.