The colours are shown, and the child led to grasp after them.

This method is of such a character as to yield a series of experiments whose results are in terms of the most fundamental movements of the infant; it can be easily and pleasantly conducted; and it is of wide application.

The child's hand movements are nearly ideal in this respect.

The hand reflects the child's first feelings, and becomes the most mobile organ of his volition, except his organs of speech.

We find spontaneous arm and hand movements, reflex movements, reaching-out movements, grasping movements, imitative movements, manipulating movements, and voluntary efforts--all these, in order, reflecting the development of the mind.
To illustrate this method, I may cite certain results reached by myself on the questions of colour and distance perception, and right-handedness in the child.
_Distance and Colour Perception._--I undertook at the beginning of my child H.'s ninth month to experiment with her with a view to arriving at the exact state of her colour perception, and also to investigate her sense of distance.