_The Origin of Right-handedness._--The question, "Why are we right or left-handed?" has exercised the speculative ingenuity of many men. It has come to the front anew in recent years, in view of the advances made in the general physiology of the nervous system; and certainly we are now in a better position to set the problem intelligently and to hope for its solution. Hitherto the actual conditions of the rise of "dextrality" in young children--as the general fact of uneven-handedness may be called--have not been closely observed. It was to gain light, therefore, upon the facts themselves that the experiments described in the following pages were carried out. My child H. was placed in a comfortable sitting posture, the arms left bare and free in their movement, and allowed to reach for objects placed before her in positions exactly determined and recorded by the simple arrangement of sliding rods already described. The experiments took place at the same hour daily, for a period extending from her fourth to her tenth month. These experiments were planned with very great care and with especial view to the testing of several hypotheses which, although superficial to those who have studied physiology, yet constantly recur in publications on this subject. Among these theories certain may be mentioned with regard to which my experiments were conclusive. It has frequently been held that a child's right-handedness arises from the nurse's or mother's constant method of carrying it, the child's hand which is left free being more exercised, and so becoming stronger. This theory is ambiguous as regards both mother and child. The mother, if right-handed, would carry the child on the left arm, in order to work with the right arm. This I find an invariable tendency with myself and with nurses and mothers whom I have observed. But this would leave the child's left arm free, and so a right-handed mother would be found with a left-handed child! Again, if the mother or nurse be left-handed, the child would tend to be right-handed. Or if, as is the case in civilized countries, nurses largely replace the mothers, it would be necessary that most of the nurses be left-handed in order to make most of the children right-handed. Now, none of these deductions are true. Further, the child, as a matter of fact, holds on with both hands, however it is itself held.