Every human individual commences his term of separate existence as a tiny speck of protoplasm, and slowly advances through the phases of separate cell-life, multicellular existence, and the gastrula, vermiform, and pisciform stages, being finally born as a partially-developed member of the human family, from which moment he grows rapidly to the perfection of the adult state, having accomplished, in the short period of about a score of years, precisely what his counterpart, the race, effected in many millions of years. During the period in which the individual dwells _in utero_ great and rapid modifications take place in the general construction of the fœtus; sensory perception makes its appearance very early, being followed quickly by the first attempt at differentiation of special sense-organs in the form of tiny surface depressions; the brain and spinal system gradually take shape and make ready for future action; and the little body slowly assumes a form suitable for separate extra-uterine existence. At the moment of birth the brain and special sense-organs are not yet developed to such a degree that they can properly discharge the functions they are called upon to perform in the mature state; they have to advance gradually to perfection in harmony with the growth of the whole body; and thus it is that a newly-born individual does not see, hear, or exhibit signs of consciousness until some time has elapsed from birth, although it is, at first, quite sensitive to cold and heat. If a lighted candle be held in front of the eyes of a newly-born infant, and moved to and fro, it will be at once observed that the child is totally unconscious of it; and, if a gun be fired off in the room occupied by the child, the effect upon the infantile organism is _nil_; but, if the air of the room be allowed to cool, the effect will be at once perceived, for the muscles of the child will soon begin to contract, and his vocal bellows to act vigorously. Gradually, however, the sight, hearing, etc., become adjusted, and the infant begins to take notice of surrounding objects, until at about a month after birth pain and pleasure, the first indications of the dawn of the mental powers, manifest themselves. Conscious, as distinguished from instinctive or non-conscious, memory appears to be exercised at about the thirteenth week, and to be immediately followed by association of ideas, the recognition of places and persons, and dreaming. At the same time that these indications of intellectual development are manifesting themselves, a corresponding unfolding of the emotions is observed. Side by side with memory appears fear, followed by pugnacity, play, and, later, anger; while, still later, about on a par with the first period of dreaming, or at about the age of five months, are manifested emulation, jealousy, joy, and grief. In about another month we notice that the child begins to understand words, while, on the emotional side, he evinces signs of