Perhaps for a screen against various dynamic vibrations, and as a receiver of other suited dynamic vibrations.

It may be that even the hair of the head acts as a sensitive vibration-medium for conveying currents of physical and vitalistic activity to and from the brain.

And perhaps from the centers of intense vital surcharge hair springs as a sort of annunciation or declaration, like a crest of life-assertion.

Perhaps all these things, and perhaps others.
But with the bursting awake of the four new poles of dynamic consciousness and being, change takes place in everything, the features now begin to take individual form, the limbs develop out of the soft round matrix of child-form, the body resolves itself into distinctions.

A strange creative change in being has taken place.