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.