The child first dimly reveals himself as thinker in the practical domain. In the evolution of the race the reasoning faculty has been first quickened into action by the ferment of instinctive craving and striving. Man began to reflect on the connexions of things in order to supply himself with food, to ward off cold and other evils. So with the child. Before the age of speech we may observe him thinking out rapidly as occasion arises some new practical expedient, as, for example, seizing a clothes-pin or other available aid in order to reach a toy that has slipped out of his reach; or clutching at our dress and pulling the chair by way of signifying to us that we are to remain and continue to amuse him. The observations of the first months of child-life abound with such illustrations of an initiating practical intelligence. Yet these exploits, impressive as they often are, hardly disclose the distinctive attributes of the human thinker. The cat, without any example to imitate, will find its way to a quite charming begging gesture by reaching up and tapping your arm. Probably the earliest unambiguous indication of a human faculty of thought is to be found in infantile comparison. When a baby turns its head deliberately and sagely from a mirror-reflexion or portrait of its mother to the original, we appear to see the first crude beginnings of a process which, when more elaborated, becomes human understanding. A good deal of comparison of this kind seems to enter into the mental activity of young children. Thus the deep absorbing attention to pictures spoken of above commonly means a careful comparison of this and that form one with another, and in certain cases, at least, a comparison of what is now seen with the mental image of the original. In some children, moreover, comparison under the form of measurement grows into a sort of craze. They want to measure the height of things one with another and so forth. An intelligent child will even find his way to a _mediate_ form of comparison, that is, to measuring things through the medium of a third thing. Thus a boy of five, who had conceived a strong liking for dogs, was in the habit when walking out of measuring on his body how high a dog reached. On returning home he would compare this height with that of the seat or back of a chair, and would finally ask for a yard measure and find out the number of inches. This comparison of things is of the very essence of understanding, of comprehending things as distinguished from merely apprehending them as concrete isolated objects. The child in his desire to assimilate, to find something in the region of the known with which the new and strange thing may be brought into kinship, is ever on the look-out for likeness. Hence the analogical and half-poetical apperception of things, the metaphorical reduction of a thing to a prototype, as in calling a star an eye, or an eyelid a curtain, may be said to contain the germ at once of poetry and of science.