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excitement is seen all over the body in consequence, but the movement excited in the arm and hand affected is the most vehement of all. This renders it not unlikely that a certain number of the nerves rising out of the hand terminate in the spinal cord, from which point of termination there are reflected back motor fibres to the muscles of the region. So by stimulating the sole of the foot, movements of the leg are excited, over and above the general excitement due to every sensation according to its intensity. Some physiologists regard the contact of the foot with the ground as a stimulus that aids in keeping up the act of walking. In like manner, by pinching the cheek or the face, the head is put in motion even in infants yet unable to localise their sensations. These reflected acts are to be included among our useful or practical instincts. In the matter of retracting a member from injury, the tendency is a protective one.

In the sense of taste we see a special responsive stimulus of the parts about the mouth, where the seat of sensation lies. A bitter taste produces wryness and contortion of the mouth: just as a bad smell operates most energetically upon the muscles of the nose. The responsive action of sight would naturally fall, either upon the muscles of the eyeball itself, or upon those that surround the orbit, and move the eyebrows and eyelids. By an action purely and unconsciously reflex and involuntary the pupil of the eye is contracted under a strong light; by an action partly voluntary, but possibly in some degree due to a special reflex connexion between the optic centres and the muscles of the orbit, the eyelids and eyebrows are drawn down under the same influence. This last action I would compare to the retractation of a pinched limb, the wry mouth under a bad taste, and the contortions of the nose by a powerful smell. I do not profess to attach very great importance to this sensori-reflex action, the whole extent of the influence of it being, as I think, but small; so much so that it would be difficult to supply an incontestable proof of its being precisely of the nature that I here suppose. At one time I was disposed to agree with Dr. Carpenter's view of Sensori-motor actions as a class apart from others, and having

a distinct and prominent efficiency, but although I freely admit the principle of a sensori-motor excitement directed especially to the organs where the seat of sensation is lodged, I think it comparatively (not entirely) insignificant both in nature and in amount.*

* Dr. Carpenter, in endeavouring to constitute a class of sensori-motor actions (Human Physiology, § 748, 4th edit.), has laid hold of a number of movements and effects due, as I conceive, to the proper diffusive influence of emotion. The involuntary laughter produced by tickling' is a part of the emotional excitement of feeling, just as the contortions of the system under pain are a part of the pain. If it be true, as I believe, that every emotional state has a diffusive influence over the body, just in proportion to the intensity of the emotion or consciousness, an infinity of movement and display must follow from the causes that stimulate pleasure or pain. So, again, to select another instance from Dr. Carpenter's enumeration, ‘those involuntary movements of the body and limbs, excited by uneasy sensation, (probably muscular), which are commonly designated as the fidgets;'this is exactly the description of an emotional outburst or expression of pain, like a start, or a groan, or a puckered countenance. He goes on to say, 'when the reflex activity of the sensory ganglia is more strongly excited, in consequence either of an unusual potency of the sensory impressions [that is, the sensations or feelings], or of an unusual excitability of these nervous centres, a much greater variety of sensori-motor actions is witnessed.' In other words, as the impressions are stronger, the diffused excitement is greater. This happens, however, not in the case of any limited number or class of sensations, but under every possible emotion that can occur to the human mind. A feeling that produces a certain excitement when feeble, produces a stronger and more varied display by being made stronger; the fact being, that such display and such movements are a constituent element of feeling, a part of its embodiment in the human frame. The movements and cries of animals during a tempest might be called sensori-motor actions; they are more properly termed, I think, the movements belonging to the emotional condition of the mind for the time being.

These movements incorporated in our constitution as a portion of the very fact of being conscious, (we are often said to be moved,' when it is only meant that an impression is made on the mind), may be called' sensori-motor,' inasmuch as a sensation, when sufficiently powerful, always visibly stimu lates them, rendering them, as it were, the return or response of the outward impression. They may also be styled 'reflex,' for the very same reason. They are, farther, 'involuntary' movements, being quite distinct from our volitional acts. But they are very far from being unconscious: they are, if I am not mistaken, inseparable from consciousness, being entwined with the conscious condition in the mechanism of our frame. When consciousness is feebly excited so are they, so feebly that no visible manifestation results; when a stronger excitement is applied, they waken up in proportion. In a cultivated shape, they make the gesticulation and display that constitutes the usual expression or natural language of feeling, which no man and no people is devoid of, while some nations show it in a remarkable degree. The painter, sculptor, poet, actor, seize hold of these movements

OF THE PRIMITIVE COMBINED MOVEMENTS.

5. The explanation already gone into respecting the functions of the cerebellum has led us to recognise certain cases of concurring or associated movements, wherein the associating link is found in the original conformation of the nerves and nerve centres. The movements of the two eyes are an example; it is by no process of education that the eyes go always together. Again, there are instances of regular sequences of movement, as in the successive strokes of the heart's action, the alternating movements of breathing, the movements of the pharynx, gullet, and intestines for propelling the food in its course through the system. There is a pre-established connexion between the consecutive acts in these various functions, such that when one movement is completed, this brings on the next, and so on, without intermission. It is interesting for us to find out to what lengths these pre-established arrangements are carried in the animal, and especially in the human, system. My object all through the present chapter is to ascertain what number of our actions grow out of primitive impulses of the muscular and nervous mechanism, in other words, what is the range or capability of the original structure of our being.

I regret to say that on this subject less assistance is to be derived from Physiologists than one would naturally have expected. Much has been written on the mechanism of animal movements, but I have not met with any writer that

as the basis of artistic forms; and the interest of the human presence is greatly dependent on them, and on the attitudes that result from them.

If I am correct in supposing that these so-called 'sensori-motor' actions are the movements due to the state of feeling or emotion that a sensible stimulus kindles, then the cerebral hemispheres are essential to their manifestation, for the cerebrum is proved to be indispensable to consciousness. Indeed, the wonderful and various diffusion of active display, that any intense feeling seems to require, as the physical part of its essence, can hardly be operated without that intermedium of multifarious connexion between all parts of the frame, which the cerebrum, with its masses of white conducting fibres, appears to afford.

has aimed at separating the primitive tendencies from the acquired Thus, for example, while the locomotive action has been most abundantly analysed, no attempt has been made to settle how far the original structure of the nerve centres determines the alternating movements of the limbs requisite for this function. It seems constantly assumed that, in the human subject at least, the power of walking is wholly acquired, like playing on the trumpet or handling a musket, an assumption that I feel myself compelled to dissent from for reasons to be presently adduced. Whether any physiologist of eminence would stand forward and deliberately affirm and defend what is thus tacitly assumed, I cannot pretend to say.

6. The locomotive rhythm involves all the arrangements that I regard as primitive in the class of combined movements of succession, apart from those organic movements of heart, lungs, and intestines above alluded to. I shall therefore proceed to adduce the grounds for believing that the combined movements of locomotion are original or instinctive.

(1.) The analogy of the inferior quadrupeds is in favour of the existence of a germ of locomotive harmony of the limbs in man. The community of structure of the vertebrate type is sufficiently close to involve such a deep peculiarity of the nervous system as this. That which nature has done for the calf towards one of the essential accomplishments of an animal, is likely to be done in some degree for man. To equip a creature for walking erect would doubtless be far more difficult, and might surpass the utmost limits of the primitive structural arrangements; but seeing that the very same alternation of limb enters into both kinds, and that nature gives this power of alternation in the one case, we may fairly suppose that the same power is given in the other also.

(2.) It is a matter of fact and observation, that the alternation of the lower limbs is instinctive in man. I appeal to the spontaneous movements of infancy as the proof. Mark a child jumping in the arms, or lying on its back kicking; observe the action of the two legs, and you will find that the child shoots them out by turns with great vigour and rapidity. Notice also when it first puts its feet to the ground; long

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before it can balance itself, we may see it alternating the limbs to a full walking sweep. It is in virtue of this instinctive alternation that walking is so soon possible to be attained. No other combination equally complex could be acquired at the end of the first year. Both a vigorous spontaneous impulse to move the lower limbs, and a rhythmical or alternating direction given to this impulse, are concerned in this very early acquisition. Let the attempt be made to teach a child to walk sidewise at the same age, and we should entirely fail for want of a primitive tendency to commence upon.

(3.) It has been already seen that the cerebellum is concerned in the maintenance of combined or co-ordinated movements. It is proved that these movements can be sustained without the cerebral hemispheres, but not without the cerebellum. But that the cerebellum should be well developed in man, and yet not be able to effect those harmonized arrangements found in the inferior vertebrata, is altogether improbable.

Unless some mode of invalidating these facts can be pointed out, the reasonable conclusion will be that there is in the human subject a pre-established adaptation for locomotive movements, which adaptation I shall now attempt to analyse.

7. First, it involves the reciprocation or vibration of the limb. Confining ourselves to one leg, we can see that this swings back and fore like a pendulum, implying that there is a nervous arrangement such that the completed movement forward sets on the commencing movement backward, and conversely. The cerebellum, or some other centre, must be so connected with the two antagonizing classes of muscles, that when one class has completed a contraction, a stimulus shall be transmitted to a ganglionic mass with returning nerves to the other class, by which nerves these are stimulated in turn, and on contracting repay the act by reviving the operation of the first. The two antagonist sets of muscles concerned in walking are chiefly members of the two great general divisions of flexor and extensor muscles. Every moving member must have two opposing muscles or sets of muscles attached to it, and