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

Confining ourselves to the strictly Reflex Actions, whether excito-motor, or sensori-motor, and omitting central spontaneity, emotional diffusion, and voluntary actions properly so called, we may now endeavour to generalize the facts, or to assign the most comprehensive laws at present attainable with regard to this process of the animal economy.

I. We trace one comprehensive arrangement, of wide prevalence throughout the animal kingdom, namely, the connexion between a peripheral stimulus and the movement of the part affected. This is the simplest and the most generalized type of the nervous system, demanding a circle made up of incarrying fibres, a central ganglion, and outcarrying fibres to the muscles of the same locality. In the lowest creatures possessing a nervous system, the structure and the function are as now described. The fixed mollusk responds to a contact by a movement contracting its body. In the experiments on decapitated animals, irritation of the foot is followed by retracting or else throwing out the limb.

Notwithstanding the higher complications super-imposed upon this simple arrangement, it is shown, almost pure, in many of the actions above described. The peristaltic movements of the intestines appear to be governed mainly by the contact with the part of the gut actually in movement. It is the same in the

pharynx and oesophagus, and also in the rectum. In coughing, sneezing, and sucking, the first stage is a reflex stimulation to the muscles of the parts irritated. In the operation of the several senses, there is a reflex stimulus of the same character, although usually disguised and overpowered by the wider and more potent influences, respectively called emotional and volitional.

We may readily speculate upon the mode of action in these simple reflex circles. The peripheral stimulation is either simple contact, as in the touch of a solid body, or contact with absorption of material fitted to act on the nerves. In both cases a muscular disturbance of the nerves takes place, which is propagated to the ganglia, and there re-inforced by the more active changes occurring in the grey corpuscular matter; whence arises a molecular movement in the outgoing or motor nerves. It is not every stimulation, however, that imparts or evolves molecu lar activity; some stimulants, as cold, under certain circumstances, tend to lower, reduce, or destroy activity already existing. The most potent stimuli, as we might expect, are nutritive materials, and substances that, by combining with oxygen, or in other ways, generate force. The rise of temperature, in its direct or immediate consequences, contributes molecular power.

II. One step above the simplest reflex movement, is the alternation of two movements, carrying the same part to and fro. Wherever an organ is fitted with an opposing pair of muscles, both these have a connexion with the ganglion related to the part; both receive outcarrying fibres, and the local stimulus will excite movements in both; which movements, however, being opposed, must alternate with one another. It is an incident of such a situation that the muscles should fall into a reciprocating movement, and establish a nervous track inclining to this reciprocation; so much so, that the completed contraction of one, without any other stimulus, is an occasion of beginning a contraction of the other. The alternating contraction of opposing pairs, whether in joint response to a peripheral stimulation, or as a result of mere spontaneity, or, lastly, as a consequence of remote nervous instigation, is a fact of very wide generality, and is the least possible remove from the simple reflex circuit supposed in the foregoing paragraph.

III. The next advance in complexity is shown in the concurrence of several distinct movements in one act. Such a con

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currence is required in deglutition, in sucking, in coughing, in forcible inspiration, in the adjustment of the eyes, and in locomotion. The regulating circumstance of the united action is the furtherance of some end in the economy. We know by what means combined movements are acquired, in ordinary education; namely, by tentatives under the guidance of the desired effect.

IV. The self-adjusting power now hinted at (to be afterwards fully elucidated in connexion with the Will) may be traced in the inferior region we have been considering. The supply of nutrition or other stimulus gives birth to molecular force, ending in muscular movement; which movement, in many circumstances, furthers the nutritive or other contact, and is thereby still further stimulated; as when the shell-fish in the sea opens its mouth to the water containing its food.

In several of the reflex actions above described, consciousness is usually present; as coughing, sneezing, sucking, the increased respiratory activity from cold, the reflex action of the senses, and the special adjustments of the ear and the eye. In so far as these actions arise during sleep, they may be regarded as independent of consciousness. But in some, consciousness is a part of the case; the object of them is, not to respond to a physical stimulation, but to remove an uneasiness; such are winking, and the adjustments of the eye to vision, and of the ear to sound. An obscure sense of discomfort is the antecedent circumstance in winking. To all these cases, we must apply the fundamental law of the will; they contain the essential fact of volition. They differ from the more usual forms of voluntary action, only in not engrossing our attention; we may be occupied with other matters while they are taking place. In this respect, they resemble actions in the stage of consummated habit.

Yet it is impossible to overlook the great resemblance to the course of voluntary action in those inferior reflex processes, commonly accounted devoid of consciousness. They are usually, although not always or necessarily, pointed to the conservation of the individual, which is the foundation circumstance of conscious and voluntary action. When several movements are united in one act, as in sucking, it is the better to answer some function of preservation.

We may not be able to draw a sharp line between the reflex involuntary and the voluntary: the two may shade into one

another by insensible degrees; and a common fact or tendency of the system may be at the foundation of both.

THE PRIMITIVE COMBINED MOVEMENTS.

4. Of the primitive combined movements, in the human subject, the leading example is the locomotive rhythm. The instinctive character of locomotion, so obvious in the inferior animals, is less apparent in ourselves, seeing that the power of walking is not possessed by us until about a year after birth. Nevertheless, there are certain strong presumptions in favour of an original endowment entering into our aptitude for locomotion.

(1.) The analogy of the inferior quadrupeds countenances the probability of a locomotive rhythm in the human limbs. The community of structure of the vertebrate type is sufficiently close, to involve such a deep peculiarity of the nervous system as this. What nature has done for the calf, towards one of the essential accomplishments of an animal, is not unlikely 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 before it can balance itself, you may see it alternating the limbs to a full walking sweep. Only in virtue of this instinctive alternation is walking so soon possible to be attained.

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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 sideways 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 probably concerned in the maintenance of combined or co-ordinated movements. We have proof that these movements can be sustained without the cerebral hemispheres, but hardly without the cerebellum. Now, 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 we shall now attempt to analyze.

5. 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 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, between these, the limb is moved to and fro at pleasure. There is obviously an organized connexion between antagonist muscles generally, so as to give spontaneously a swinging or reciprocating movement to the parts; in other words, when any member is carried to its full swing in one direction, there is an impulse generated and diffused towards the opposing muscles, to bring it back, or carry it in the other direction. Of course this reaction will be most strongly brought out, ou occasions when the commencing