expressing the reflex action of nervous currents, he would undoubtedly have given vent to his spleen at the influence of foreign savants in even bitterer terms than those in which he indulges. But such indignation would have been as misplaced as the terrors of some modern divines are. Every new idea creates an enthusiasm in the minds of those who have first grasped it, which renders them incapable of viewing it in its true proportions to the sum total of knowledge. It is in their eyes no new denizen of the world of facts, but a heaven-sent ruler of it, to which all previously recognised truths must be made to bow. As time goes on, truer views obtain. The new principle ceases to be regarded either as a pestilent delusion or as a key to all mysteries. Its application comes to be better defined and its value more reasonably appreciated, when both idolaters and iconoclasts have passed away, and a new generation begins to take stock of its intellectual inheritance.

The book of Dr. Carpenter is an attempt to mediate between the extreme Psychologists and Physiologists. He regards the causative power of the human will, and the self-determined condition of the individual man in the exercise of it, as primary facts of which we have the complete evidence in our own consciousness. But not the less does he accept, with certain limitations, the doctrines which the Physiological School urge as incompatible with such a view. He frankly confesses their merits at the

outset.

'What modern research seems to me to have done, is to elucidate the mechanism of Automatic action; to define with greater precision the share it takes in the diversified phenomena of Animal life, psychical as well as physical; and to introduce a more scientific mode of thought into the Physiological part of the inquiry. But in so far as those who profess to be its expositors ignore the fundamental facts of consciousness on which DesCartes himself built up his philosophical fabric, dwelling exclusively on Physical action as the only thing with which Science has to do, and repudiating the doctrine (based on the uni

versal experience of Mankind) that the mental states which we call Volitions and Emotions have a causative relation, they appear to me to grasp only one half of the problem, to see only one side of the shield. That the principle of the conservation of Energy holds good not less in the Living body than in the

Inorganic world, I was myself among the earliest to maintain. That in the most powerful the Human Will, there is no more a creation muscular effort which can be called forth by of Energy than in an Automatic convulsion, I believe as firmly as Professor Clifford. And that the general tendency of modern scientific research is to extend the domain of Law to every form of mundane change-the belief in the Uniformity of Causation being now assumed as axiomatic in all scientific procedure-I recognise as fully as Mr. Herbert Spencer.'-Preface, p. xvi.

There is no question that automatism, including in that term both mental and bodily activities, plays a very large part in the life of every one. What the limits of that part are is the real question at issue, and this it is the object of Dr. Carpenter's work to point out. The book is, in fact, a survey of the borderland between the region of Physical Causation and Moral Causation, taking its departure from the ground of the physiologist. It naturally enters largely into anatomical details, which however necessary for the establishment of the author's argument in the minds of his fellow-experts, are the reverse of attractive to the general reader. We will therefore endeavor to spare him as much of these as we can without injury to the understanding of the case.

That all our knowledge of the external world arises from the impressions made upon our senses is allowed by all philosophers of whatever school since. the time of Locke; but the really important point to ascertain is, whether, in the very act of acquiring this knowledge, we have not evidence of something more than the external worldthat is, of the Ego, the sentient subject, our own personality. It might be possible to acquiesce in a denial of this, if the whole of our existence consisted of one unvarying, single sensation; but as soon as ever any the least variation of this is perceived, personality shows itself in its simplest form, viz.—as the identical subject of two diverse sensations. Let us merely suppose these sensations multiplied and varied, each in its turn leaving its trace in the shape of a remembrance, and the result will be something analogous to what is continually experienced in a dream, where image after image springs up in an apparently arbitrary manner, the sleeper bearing no other

part in it than that of the spectator of a moving phantasmagoria.

Now in this simplest form of personality there is not involved the idea either of knowing or of acting. The Ego is in it nothing more than the passive recipient of a string of impressions. He can have no thought either of any law by which this succession is regulated, or of any power in himself of modifying them. We will, however, proceed a step further. Let us suppose these sensations divided into several similar groups. The observation of this regular recurrence constitutes an elementary knowledge for the Ego. He apprehends an order by which his sensations follow one another. Now, let us suppose that these groups, though infinite so far as appears in number, are divided into several classes (which we will denote by the letters of the alphabet), so that there are several A's, several B's, several C's, and so on; and, further, that an A is always succeeded by B, sometimes but not always, also by C, and never by D. The Ego now increases his stock of knowledge, but it is still a communicated, not an acquired knowledge-it is the knowledge of an observer pure and simple, not of a thinker; it is the knowledge of Flamsteed, while noting and tabulating the lunar movements, not the knowledge of Newton, deducing from those movements the law of gravitation. The Ego, by acquiring this knowledge, has become an ens sciens, but as yet is in no respect an ens agens. agens. And however much we may suppose the groups of sensations varied and complicated, and in consequence the aggregate of the communicated knowledge increased for the Ego, he remains still altogether passive, the product (except so far as conciousness is concerned) of external forces, as much as the mature plant is the product of the pains bestowed upon it by the gardener. If then the matured powers of the man are really developed out of simple sensations by a similar process, however wonderful and elaborate, it can not be contested that he must be classed in the same category as the plant.

But now let us see how far the phenomena even of infancy warrant any such conclusion. Our classes of sensations, just now denoted by the letters

of the alphabet, are here those which reach the sentient subject, the infant, through his several senses. The physiologist teaches us that in sight, for instance, a certain impression is made on the retina of the eye, just as in photography an impression is made on prepared glass; and the first effect of this is to generate nerve-force in the optic nerve along which it is transmitted to the ganglionic centre of the latter, which forms part of the sensorium.* The olfactory and the auditory nerves perform a precisely similar function in the case cf smelling or hearing. All these nerves have in themselves no sensation; their sole employment being to convey, like a telegraph, the message from without, and they may be pricked or pinched without evoking any sign of pain. It is altogether different with the nerves which minister to the power of movement, as well as convey to the Ego the information supplied by the senses of touch and of muscular resistance, and which, on this account, have received the name of the sensori-motor nerves. Microscopic observation exhibits them as bundles of minute fibres, of which each is isolated from the rest, like the wires in a submarine cable, by a peculiar substance known as the 'white substance of Schwann.' They are of two distinct kinds the afferent, which convey to their proper ganglionic centres the sen-. sations indicated by the touch, and the sense of muscular resistance, and the efferent, which, proceeding from these ganglionic centres, produce movement in the appropriate members through muscular contraction. The combination of the two is like a compound telegraphic arrangement, by which information is transmitted from the point A to the point B, and orders derived from that information (not the information itself) forwarded at once to a third point C. In many cases, this is purely an automatic proceeding, as, for instance, when the soles of the feet are tickled, the involuntary result is a twitching convulsion of those members. But in others

By this term may be understood the aggregate of the ganglia in which the spine and the several nerves centre, lying under the higher hemispherical portion of the brain, the cerebrum.

the volitional character is manifest, as when we find by our sensations that a weight carried on the shoulder is awkwardly placed, and therefore we vary its position to render it more tolerable.

Now, the first manifestation of volitional movement in the infant is undoubtedly obscure. He turns in his cradle towards a light; and this is doubtless an automatic result occasioned by the attraction of its brightness. But the same can hardly be said of his handling an object presented to him, which, if in its origin stimulated by an external impulse, almost instantly assumes another character, when he places the object at different distances from his eyes, carries it to his mouth, turns it in various ways, strikes it against the side of his cradle, and endeavors to pull it to pieces. It is impossible for any one who watches these acts to conceive them to be nothing else than a sequence of phenomena, each springing out of the one preceding it by a mechanical necessity. There is manifestly a comparison going on of the different sensations that have been excited; and comparison in its most elementary form implies attention, that is, concentration upon some portion of what ever is presented to the Ego to the comparative neglect of the rest. Indeed, it seems undeniable, that even in any single experience of muscular resistance, there must be awakened the consciousness of a force to the exercise of which that resistance is offered; in which case the evidence of the existence of the Ego as an active force, can not but be regarded as arising contemporaneously with that of the existence of the non-Ego-the external world, the limit of such active force.

Automatism, however, undoubtedly plays a very large part in the bodily actions, and, according to Dr. Carpenter, in mental operations also. The acts of breathing, of coughing, and of sneezing are mainly independent of the will. The muscular movements which effect them are evoked by agencies over which the will has no control. The beating of the heart is even more striking. It may be, and often is, modified by emotion, but never by a simple effort of will without the presence of emotion. It is obvious that but for this automatism, in many cases, there would be no security for the

The

maintenance of life. The circulation of the blood would cease from mere neglect of the agency which keeps it in motion. But this Primary Automatism, as it may be called, yields in interest for the present purpose to Secondary Automatism, a name given (first by Hartley) to actions which come to be performed by habit without will, or even consciousness; but which were originally learned by volitional effort. Walking is the most obvious example of this class of actions. The power is attained gradually, and at the cost of considerable pains. mere balancing of the body in a standing position involves the combined action of almost every muscle; and the advance of the most finished acrobat beyond this achievement is far less than that which he must have made in acquiring it. Yet it is a matter of daily experience that in walking we pay no attention whatever to what we are doing after once determining in what direction we shall proceed. Very generally we are altogether absorbed in conversation with a companion, or, perhaps, in meditation on some subject which happens to occupy our minds. Mr. Mill thought out the greater part of his 'System of Logic' during his daily walks between Kensington and the India House; and no one who passes through the Bank of England, during business hours, will be able to fancy that, of the hurrying crowd he sees, a single individual is bestowing a thought upon that 'co-ordination of his muscular actions,' without which it would, nevertheless, be impossible for him to carry his dividend-warrant to his banker's.

But let us suppose one of these men of business suddenly seized with blindness. He would instantly stop in his career, although just before, while hastening over familiar ground, and taking no heed of anything but the matter uppermost in his thoughts, he was utterly unconscious that his eyes were rendering him any service at all. Here, then, it is plain that not only was there a mechanical co-ordination of the locomotive muscles, but likewise co-ordination between them and the visual organs. Yet of this the merchant had not the slightest conception. From the time he set out, therefore, he has been the subject of an extremely complicated automatism, no volition having been exerted by him any

more than after having put himself into a cab, volition would have been exerted by him in driving it. The whole act of going from place to place is, of course, volitional; but the volitional character of it does not permeate the entire sequence of motions, but is derived from the initial purpose. The merchant wills to go to his banker's, and he wills to go by walking. His purpose brings his eyes and limbs into action, and between them they perform the operation which he desires to see effected; but they, nevertheless, perform it automatically, his will no further interfering after having once given its command, and his attention being occupied by altogether different matters. The important part played by the cooperation of the senses, of which we are all the time unconscious, is exhibited most clearly in some cases of accident. Thus the sensory nerve of a limb may be paralysed, while the force of the motor nerves of the same limb remains. But the latter can not by any effort of the will be brought into action (the sense of muscular resistance being lost through the paralysis of the sensory nerve) without the aid of the eye. A woman thus affected found that she could not support her infant on her arm without constantly looking at it. The removal of her eyes for a moment, in spite of her knowledge that the child was resting on her arm, and of her desire to sustain it, was at once followed by a relaxation of the contracted muscles.

The reflex movements, as those are called which are produced by the motor (or efferent) nerves in response to the messages conveyed through the afferent nerves, are not necessarily accompanied by feeling.

If the head of a frog be cut off, and the spinal cord be divided in the middle, so that the forelegs remain connected with the upper part, and the hind legs with the lower, each pair of members may be excited to movement by a stimulus applied to itself, but the two pairs will not exhibit any consentaneous motions, as they will do when the spinal cord is undivided.' }

In a case of paralysis of the lower extremities, recorded by Hunter, the patient was asked whether he felt the irritation by which 'reflex movements' in his legs were produced, and replied, 'No, sir, but you see my legs do.' In

two cases of injury to the spine, recorded by Dr. William Budd, in which sensibility of the legs was for a time nearly destroyed, and voluntary action entirely. so, violent contractions followed the tickling of a feather in the hollow of the instep, although the patient was quite unconscious of the cause of them. It is remarkable that in these cases, as recovery (which took place very slowly), progressed, and voluntary power gradually returned, the susceptibility to the involuntary reflex movements diminished.

Dr Carpenter holds that the will, when carrying into action a determination of the intellect, does not act directly upon the muscles which execute the mandate, but indirectly through the automatic mechanism, of which the act of walking, as we have just seen, furnishes a familiar example. The head-quarters (so to speak) of this mechanism is the axial cord, receiving, as it does, all the nerves of sense and giving out all the nerves of motion; and this, under different modifications, is found in all animals.

'We should form,' says Dr. Carpenter, 'a very erroneous notion of what essentially constitutes the brain of a Vertebrated animal, and of the mutual relations of the aggregate of ganglionic centres of which it is composed, if we were only to study it in Man. For the great relative size and complexity of his Cerebrum tends to conceal the fundamental importance of those ganglionic centres on which it is superposed, and which constitute no less an important part of his brain than they do of that of Fishes; although their proportional size is so much less as to lead to their being commonly regarded as merely subordinate appendages to the Cerebrum. The brain of a FISH is almost entirely composed of an aggregate of ganglia of Sense, which may be resorium, that is, according to ordinary phrasegarded as collectively constituting its Senology, the "seat of consciousness," but, more strumentality of which the Ego becomes concorrectly, the Nerve-centre, through the inscious of Sense-impressions. Putting aside the rudimentary Cerebrum, therefore, we may regard the Axial Cord of the Fish (consisting of its Spinal Cord with the Sensory ganglia) as the instrument, like the gangliated cord of the insect, of its automatic movements; of which such as are executed through the Spinal centres do not involve Sensation, whilst in those of which the Sensory Ganglia are the instruments, Sensation necessarily participates. When, on the other hand, in ascending the Vertebrate Series from Fishes toward Man, we compare the different grades of development of the Cerebrum with the successively augmenting manifestations of intelligence (as exhibited in what we must regard as

an intentional adaptation of means to ends under the direction of experience), we find so remarkable a correspondence as scarcely to leave room for doubt that the Cerebrum is the instrument of those Psychical operations which we rank under the general designation, rational. In proportion as the actions of an animal are directed by this endowment, the number of them that can be said to be primarily automatic becomes not only relatively but absolutely limited; although many actions (especially in Man) which were in the first instance initiated by the Will, come after long habit to be as truly automatic as if they had been so originally.'-P. 64.

After tracing the increasing relative magnitude of the cerebrum (or its analogue), as we ascend the scale of vertebrates from its lowest member, the fish, to its highest, man, Dr. Carpenter proceeds to that portion of his work which will chiefly interest the bulk of his readers-the inquiry into the mode in which this highest organ, the cerebrum, is subservient to those higher mental operations, the capacity for which specially characterises man, though among some of the other mammalia may be found (he thinks) distinct approximations to it. The general fact, that the development of the cerebrum indicates the predominance of intelligence over instinct, is universally allowed; and the principle seems to hold good to a great extent, not only when we compare different races of mankind, but even different individuals of the same race.

The anatomical distinction between

the cerebral hemispheres of man and the analogous organ of other animals shows itself especially in the complexity of the arrangement of the nerve fibres of which the medullary substance is composed.

'These may be grouped under three principal divisions. The first, which may be distinguished as the radiating fibres, connect the different parts of the Cortical layer* with the

Sensori-motor tract on which the Cerebrum is superposed; and it is probable that there are two sets of these, one ascending from the ter

*This 'Cortical layer' consists of nervecells spread out on the surface of the cerebrum; not as is the case with ordinary ganglia, of which latter they form a sort of internal nucleus. It is covered by the membrane call

minals* of the sensory tract of the Axial Cord to the Cortical layer, and conveying to it the result of the physical changes produced in them by the Sense-impressions which they receive; the other descending from the Cortical layer to the terminals † of the motor tract of the Axial Cord, and conveying to them the Physical results of the changes which take place in itself. These fibres, which bring the instrument of Intelligence and Will into relation with that portion of the nervous apparatus which furnishes the Mechanism of sensation and of the automatic or instinctive motions, were called by a sagacious old Anatomist, Reil, the nerves of the internal senses. The second set of fibres brings the several several parts of the Cortical layer into mutual communication. The arrangement of these commissural fibres is peculiarly complex in Man. The third set of fibres, termed intercerebral, connects the two hemispheres of the Cerebrum together by a broad band. This also is much more developed in Man than in any of the lower Mammalia. It is altogether wanting in Fishes, Reptiles, and Birds. There is a rudiment of it only in Marsupials and Rodials. Cases have occurred in which it has been nearly, or even entirely, deficient in Man; and it is significant that the chief defect in the characters of such individuals has been observed to be a want of forethought, i.e., of power to apply the experience of the past to the anticipation of the future.'-P. 99.

There is no indication, in the case of man, of a transfer to the cerebrum of the

proper attributes of the other nervous apparatus. Its substance is insensible, and no physical impression made upon been removed from pigeons, the sensory it is felt by the subject of it. It has ganglia being left intact; and the respondent motions to external impressions have remained unaltered. The bird

seeks out the light parts of a partially illuminated room, and avoids objects that lie in its way. If thrown into the air it flies, and when sleeping at night, with closed eyes and its head under its wing, is roused by the slightest noise, just as in its normal condition.

There is, however, according to Dr. Carpenter, one characteristic of the cerebrum which is common to it and to the sensori-motor nerves-it is subject to reflex automatic action. Regarding memory, from his point of view, as the 'psychological expression of physical changes in the cerebrum,' he considers 'traces'

* The 'Thalami Optici.' The Corpora Striata.' The 'Corpus Callosum.'