The habit of digression—lack of continued interest— want of fixed purpose, is an almost general failing. It is too easy to drift and the habit of letting oneself drift begets drifting. The power of concentration is rare and must be sought and cultivated, and prolonged work on one subject must not be mistaken for concentration. Prolonged work on one subject may be simply prolonged digression, which is a useless effort, as it is to no end.
