"Enthusiasm - a distemper of youth, curable by small doses of repentance in connection with outward applications of experience"

This quote by Ambrose Bierce recommends that interest is a quality of youth that can be treated with a mix of reflection and experience. Bierce indicates that enthusiasm is a sort of "distemper," or illness, that can be treated with "small doses of repentance" or regret for previous actions, and "outside applications of experience," or the knowledge got from life experiences. In other words, as we age, we ought to gain from our mistakes and become more familiar with the effects of our actions. This quote suggests that interest is a natural part of youth, however that it can be tempered with age and wisdom.