"There are some trees, Watson, which grow to a certain height and then
suddenly develop some unsightly eccentricity. You will see it often in
humans. I have a theory that the individual represents in his
development the whole procession of his ancestors, and that such a
sudden turn to good or evil stands for some strong influence which came
into the line of his pedigree. The person becomes, as it were, the
epitome of the history of his own family."