attempts to fix the date of the appearance of a particular kind of mental activity, the difficulty is increased by the fact that in infancy mental processes are so intricately interwoven with organic, semi-conscious phenomena that the dawn of a particular kind of consciousness cannot be determined. We have seen a bed of plants whose stems above ground stood apart from the stems of the neighbouring plants, and we have thought it not impossible to trace to their remotest ends the roots of the individual plants. But when we dig beneath the surface, we may find that the stems above ground have sprung from a common root-stock, or that the roots have grown together and form a mass, an inextricable net-work of rootlets so that the search for the roots of a particular plant is in vain. The child's several abilities and functions arise out of a net-work of instinctive tendencies which may be likened to the intertwined and tangled rootlets from which spring the separate plant stems. In both cases,
about the room, and the new method of creeping on hands and knees developed rapidly, so that the note for the eighth day of the second year reads, "The child creeps everywhere about the house on his hands and knees, and with evident enjoyment. He seems eager to creep, does not want to be held on one's lap, wants to creep just for the fun of creeping." This, as was said, was the only acquired ability noted which was not slowly developed by practice. And in this case, one cannot be sure that there was not preliminary practice in resting on the hands and knees which escaped our notice—for instance, moving about when he was in his crib after his nap was over, and before he made an outcry to let us know that he was ready to be taken up.
