25. It should be added that some secondarily automatic actions have become so firmly organized that we can only with great difficulty interfere with them. Others never enter into consciousness, and are therefore often supposed to be purely mechanical. The movement of the eye towards the brightest light, and the convergence of the axes of both eyes, are reflexes which, although involuntary and unconscious, are the products of education. They do not belong to the connate constitution, although they are so inevitably acquired by experience that they belong to every normal child. At first the infant stares with a blank gaze, and its eyes, though moving under the stimulus of light, move incoherently; the axes never converge except by accident. Very early, however, the infant’s eyes are observed to follow the movements of a bright light; and at last they acquire so certain and rapid a power of adjustment that the eyes shift from spot to spot, always “fixing” the object by bringing the most sensitive part of the retina to bear on it. The incoherent movements have become precisely regulated movements. It is the same with speech. The vocal organs are exercised in an incoherent babble. By degrees these movements become regulated so as to respond definitely to definite stimuli, and words are formed, then sentences, till finally fluent speech becomes in a great degree automatic. The vocal muscles respond to an auditory stimulus, and the child repeats the word it has heard, just as the eye-muscles respond to a retinal stimulus. That we acquire the power of converging the axes, and accommodating the lens to near objects, is not only proved by observation of infants, but also by cases of disease. After the reflex mechanism has been long established, so that it acts with inevitable precision, a slight paralysis of one of the muscles has the effect of making all objects appear in a different position; the patient trying to touch an object, then always moves his hand on one side of it. Von Graefe relates the case of a stonebreaker who always struck his hand with the hammer when he tried to strike the stone. Yet this very man _learned_ to accommodate his movements to the new impressions; so that if his paralysis had been cured, his modified mechanism would have been ill adapted to the new conditions, and he would once more have struck his hand instead of the stone.