In all animals in which well-differentiated nervous systems are found, in which there are distinct nerve-fibres and nerve-centres, reflex actions, simple or more complicated, occur. They form the initial steps leading up to the highest types of organic behaviour. So long as the nervous arcs--afferent fibres, nerve-centre, and efferent fibres--remain intact reflex acts may be carried out with great precision and delicacy, even when the higher centres, which we believe to be those of conscious guidance and control, have been destroyed. When, for example, the whole of the brain of a frog has been extirpated and the animal is hung up by the lower jaw, if the left side be touched with a drop of acid the left leg is drawn up and begins to scratch at the irritated spot, and when this leg is held, the other hind leg is, with seemingly greater difficulty, brought to bear on the same spot. “This,” says Sir Michael Foster, “at first sight looks like an intelligent choice.... But a frog deprived of its brain so that the spinal cord only is left, makes no spontaneous movements at all. Such an entire absence of spontaneity is wholly inconsistent with the possession of intelligence.... We are therefore led to conclude that the phenomena must be explained in some other way than by being referred to the working of an intelligence.”[13] But if we concede that intelligence is absent, may there not at least be some consciousness? Sir Michael Foster’s reply to such a question goes as far as we have any justification for going, even when we give free rein to conjecture. “We may distinguish,” he says, “between an active continuous consciousness, such as we usually understand by the term, and a passing or momentary condition, which we may speak of as consciousness, but which is wholly discontinuous from an antecedent or from a subsequent similar momentary condition; and indeed we may suppose that the complete consciousness of ourselves, and the similarly complete consciousness which we infer to exist in many animals, has been evolved out of such a rudimentary consciousness. We may, on this view, suppose that every nervous action of a certain intensity or character is accompanied by some amount of consciousness which we may, in a way, compare to the light emitted when a combustion previously giving rise to invisible heat waxes fiercer. We may thus infer that when the brainless frog is stirred by some stimulus to a reflex act, the spinal cord is lit up by a momentary flash of consciousness coming out of the darkness and dying away into darkness again; and we may perhaps infer that such a passing consciousness is the better developed the larger the portion of the cord involved in the reflex act and the more complex the movement. But such a momentary flash, even if we admit its existence, is something very different from consciousness as ordinarily understood, is far removed from intelligence, and cannot be appealed to as explaining the ‘choice’ spoken of above.”[14]