Just as fire catches readily in chaff, fibre, and hares' fur, but goes out
rather quickly, unless it gets hold of some other thing that can retain it
and feed it, so the keen love between newly married people that blazes up
fiercely as the result of physical attractiveness must not be regarded as
enduring or constant, unless, by being centred about character and by
gaining a hold upon the rational faculties, it attains a state of vitality.