But this simple function was disturbed by the wants of life, which likewise furnish the impulse for the further development of the apparatus. The wants of life first manifested themselves to it in the form of the great physical needs. The excitement aroused by the inner want seeks an outlet in motility, which may be designated as “inner changes” or as an “expression of the emotions.” The hungry child cries or fidgets helplessly, but its situation remains unchanged; for the excitation proceeding from an inner want requires, not a momentary outbreak, but a force working continuously. A change can occur only if in some way a feeling of gratification is experienced — which in the case of the child must be through outside help — in order to remove the inner excitement. An essential