Consequently, two successive phases of uninterrupted work are left; one may be called the _phase of preparation_, the other the _phase of serious work_. The phase of preparation lasts a very short time, the _serious work_ is of much longer duration; it is noteworthy that the period of _rest_, with its characteristic air of _comfort_ and _serenity_, sets in after the _maximum effort has spontaneously spent itself_. On the other hand, it happens invariably that any external interruption of the effort causes the child to show signs of fatigue (restlessness), or to become inattentive. In the first curve, the initial work consists of two easy tasks, carried on for a short time, and from these the child passes directly to the serious work. The finale is a spell of rest full of thought; the child ceases to work, but contemplates his finished task for a long time in silence; before preparing to put it away, or, after having contemplated his own work, he goes quietly to watch that of the others. In the second curve there is a very noticeable parallelism with the line of repose; the child pursues his labors almost uniformly, and the sole difference between the initial work and the serious work is in their different duration. The contemplative period becomes henceforth an obvious "period of internal work," almost a period of "assimilation" or "internal maturation." Observation of the work of others becomes increasingly frequent, as if it were a spontaneous "comparative" study between the child himself and his companions; or as if an active interest in the contemplation of the external surroundings were developing: the period of discovery. We may say that _the child studies himself in his own productions and puts himself into communion with his companions and his environment_.