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ART VI.-PHYSIOLOGICAL PSYCHOLOGY.

No. II.

BY ROBERT DUNN, F.R.C.S. ENG.

(Continued from page 240.)

THE scientific procedure of psychology, according to Fichte, essentially consists in separately considering the intelligence, the feelings, and the will, and in carefully observing and studying their parallelism in the different stages of mental development. We have considered the unity of the mind in self-consciousness, -its earliest, and consequently lowest, phase of development— in sensori-motor, consensual, and instinctive feelings and actions; where the intelligence is purely sensational, the feelings simply those of pleasure and pain, and the impulses to action inherent and instinctive.

We have now to consider it in the perceptive consciousness, the next stage of our psychological progress, in ideation, emotion, and volition; and here, too, there exists a perfect unity at the root, from these being so closely interwoven with each other. For without ideation there can be no determinate or voluntary action, and without the will no act of intelligence; while alike with both and with either, emotional sensibility is indissolubly connected.

The genesis of the will is in the perceptive consciousness, and it proceeds, pari passu, with the development of the intellectual faculties, until they reach their dominant development-the highest reason and the freest will ;-and then it is that an act of the will embodying the whole man emphatically implies, at the same time, intelligence, emotion, impulse. But when the perceptive faculty is in abeyance, the will is in abeyance, and memory is abolished. Of this we had a striking illustration in the young woman's case, to whom I have before alluded. In her the mental faculties were quite suspended, and all the avenues to the sensational consciousness were closed, with the exception of sight and touch, for she could neither hear nor speak, smell nor taste. Her mind was in a state of isolation, and even through sight and touch no ideas were aroused, for the perceptive faculty was in abeyance, but the will was in abeyance also, and memory she had none. She had no notion that she was at home, nor the least knowledge of anything about her. She did not even know her own mother, who attended upon her with the most unwearied attention and kindness. Wherever she was placed there she remained throughout the whole day, making not the slightest voluntary effort of any kind, manifesting no uneasiness for anything to eat or to drink, and taking no heed whatever of what was going on around her." In fine, while the

perceptive faculty was benumbed and paralysed, ideation, memory, and volition were alike abolished.

Perceptive Consciousness. Sensory impressions, the intuitions of the special senses, whether sights, sounds, smells, tastes, or feelings, internal or external, in order that they may reach the perceptive consciousness, and so become idealized and registered, require to be transmitted from their respective sensory ganglia to the great hemispherical ganglia, or cerebrum, for it is there that ideation is effected, and memory resides. But if, indeed, the perceptive faculty should become suspended, then "all the enjoyments of the feast, all the fragrance of the flowers, and the whole of the associations which they embody, vanish as with a single and magic stroke."* And, as in this young woman's case, the most nauseous medicines would be taken quite as readily as the most delicious viands. Such, too, is the fate of all our associations in connexion with the higher and more objective of the senses, with hearing, feeling, sight. For the whole world of tone,—the grandest harmony, the softest melody, the living voices of nature, exist not when the percipient power is in abeyance; nor without its agency can our tactile sensibility impart to us any knowledge of the bodily substances by which we are impressed, or identify the impressions with the forms of the external objects that produced them. And as for light-to what do the intuitions of light and colour amount without the perceptive faculty, and what the pictured image on the retina without the perceptive organ beyond it? To the eye, without the perceptive faculty behind it, "the universe would be all dark and dreary, not a tint or a hue there, not a smile on the face of nature, nor a shade of beauty on the summer's landscape." And thus it is that perception is the portal to intellectual action; for while in sensation, the conscious mind feels intuitively the physical impulse of the outward object as it affects the consciousness through the sensorium, in perception the nervous impression is carried a stage farther, and by virtue of the harmony which exists between the percipient mind and the external world or nature, the sensory impression is intuitively translated into the form of intelligence, and becomes an intellectual phenomenon; in other words, it is perceived and idealized. The process in both cases is equally and alike intuitive. For when we look at an external object, we can no more avoid the perception that it is a something distinct and apart from ourselves, and of having forced upon our minds intuitive ideas as to its size, shape, colour, &c., than we can reject the sensations of touch, as to its hardness or softness, or those of taste as to its sweetness or bitterness, or of smell, as to its fragrance or offensiveness; in each and in all, the * Morell's Psychology.

+ Ibid.

process is alike intuitive. But these two states, nevertheless, of consciousness,sensation and perception, though both intuitive and so closely allied, are not to be confounded, for they are distinct, and the mechanism (so to speak) of their action is different. The one is a single, and the other a complex act. In sensation it is direct and single, for the impressions made on the sensory ganglia go direct to the sensational consciousness; but perception is a step in advance in our psychological progress, above sensation, and in it a double ganglionic action is involved. For the sensory impressions to become perceived, that is, idealized and remembered, they require to be transmitted from the sensorium to the cerebrum, "the sole receptacle," in the language of Cuvier, "where the various sensations may be, as it were, consummated, and become perceived by the animal, and where all sensations take a distinct form, and leave lasting traces of their impressions, serving as a seat to memory, a property by means of which the animal is furnished with materials for its judgments.'

In illustration of this view, Dr. Noblet has well observed:

"An anatomical distinction between the region of thought and that of sensibility can very fairly be established; and a certain aptitude, moreover, can be recognised in the encephalic structure for conveying the impressions of the senses upwards to the hemispherical ganglia. White matter intervenes between the vesicular neurine of the sensory ganglia and that of the cerebral convolutions; the conscious impressions received by the former may be regarded as ascending along the white fibres, and, on the gray summit being attained, developing changes in its condition which minister to intelligence. Ideas arise. If we reflect upon the processes that go on within our own minds, there is no difficulty in distinguishing between a sensation and an idea, or in marking the sequential origin of the latter. How often do we find that, when the full consciousness of sensation is obtained, the idea suggested by it does not follow until some seconds, or even minutes afterwards. For example, you hear the utterance of certain words as sounds; their signification does not strike you; no effort of attention is made, yet suddenly the sense breaks upon your intelligence. The correlated physiological phenomena may be thus stated. The auditory ganglia take up the sentient impression at once; its passage onwards to the seat of thought is delayed; presently, however, its natural course is freed, as if from some hindrance, and it attains the hemispherical ganglia, forming or awakening ideas in the mind."‡ *Cuvier, Rapport sur le Mémoire de Flourens sur le système nerveux, quoted by Dr. Todd. Vide "Cyclopædia of Anatomy and Physiology, and Functions of the

Nervous System."

+ Vide Dr. Noble's Lectures "On the Co-relation of Psychology and Physiology," page 27.

The modus operandi of Anæsthetic agents, in relation to their action upon the different nervous centres of the encephalon, is highly interesting and instructive. It brings strong confirmation to the important facts, that sensation and perception are distinct states of consciousness, that they have their seat in different nervous

Before entering, however, upon the consideration of the phenomena of the perceptive consciousness, and of the local habitation of its organs in the cerebrum, I think we shall proceed with decided advantage, in reference to the physiological bearings of the subject, seeing that throughout the entire vertebrate subkingdom, the type of the brain is the same,-if we first pass in review the whole of the ganglia of the encephalon, and endeavour to specialize their functions, beginning with the lowest of the

centres, and that the sensational consciousness may be suspended, while the perceptive remains intact. As bearing on these points, I brought the subject of "the inhalation of chloroform, its anaesthetic effects, and practical uses," under the notice of the Royal Medical and Chirurgical Society, in a paper, which was read and discussed, April 22, 1851, and afterwards published in the Medical Gazette of the same year. In illustration, I may here cite the following paragraphs:

"There can be no doubt that the anesthetic effects of the inhalation of the vapour of chloroform are due to its entering the circulation, and to its being carried by the blood to the vesicular matter of the sensory ganglia, and to the cells, or cell nuclei, at the peripheral extremities of the afferent nerves. And while it is reason. able to infer that, in thus circulating with the blood through the encephalon, its presence, like that of any similar morbific agent, must more or less affect all the sensory feelings and psychical manifestations, it is nevertheless abundantly manifest that a kind of elective affinity exists, by virtue of which the vesicular matter of one centre of action becomes affected before that of another; for, during the slow and gradual inhalation of the vapour, the function of sensation is suspended before that of intellectual action,-the consciousness of feeling is obliterated, and consequently immunity from pain secured, before intellectual consciousness is totally abolished. M. Flourens was, I believe, the first to point out the tendency of certain morbific agents to act primarily and specially on one nervous centre in preference to that of another, by virtue of some special elective affinity between such agents and certain ganglia of the encephalon.

"From the records of personal experience, and from a careful consideration of the phenomena observed in others, we may trace the following order and sequence in the effects of the inhalation of the vapour of chloroform, properly diluted, upon different nervous centres.

"Thus, the first few inhalations are attended with feelings which indicate disturbance in the action of the sensory ganglia, as singing in the ears, a sense of numbness, and tingling of the surface of the body,' &c., but which are soon succeeded by a transient stage of more general excitement; of delirium in the hemispherical ganglia, for instance,— -as singing and incoherent talking, and of excited emotional impulses, and consensual movements in the sensory ganglia,-as laughter and uncontrollable motorial actions; this is speedily followed by suspension of the function of sensation, the consciousness of feeling, while as yet some degree of intel lectual activity remains. Sensorial impressions from without are no longer transmitted from the sensory ganglia to the cerebrum; but this suspension of ordinary sensational impressions, as in sleep, with persistent intellectual activity, is the typical characteristic of dreaming;' and dreams often occur. The commissural fibres, between the cerebrum and these ganglia, Reil's nerves of the internal senses, being still in action, they transmit downwards the residual intellectual activity from the cerebrum to the sensory ganglia, and frequently give rise to manifestations, which impress the mind of common observers with the belief of pain and suffering being felt under the knife of the surgeon, while in reality there are none. "The function of the cerebrum as the centre of intellectual action is next suspended; a state of coma is induced, a complete abolition of consciousness, reducing life to a series of automatic movements. After this the medulla oblongata and true spinal centres become involved, reflex action is stopped, and breathing by the ribs suspended. The ganglionic system is the last to be implicated; but, with the arrest of the peristaltic action of the heart, life ceases."

vertebrate series, and thus "making use of the lower animals, as so many experiments ready prepared to our hands by nature." In man, indeed, the cerebrum is so enormously developed, that it completely overlaps and crowns the other encephalic ganglia, whilst in the lowest of the series its representative is reduced to a mere lamina or crust. Now, proceeding in this way, if we advert to the brain of the fish, the lowest in the series of the vertebrate sub-kingdom, and where there exists the least complexity of structure, what do we find? And of what are the ganglionic bodies which we do find, the homologues in the human encephalon? We find, in the brain of the fish "a series of at least four distinct ganglionic masses, arranged in a line continuous with the spinal cord, three of them in pairs, and the last or hindmost single." Respecting these, a rigid scrutiny and a strictly philosophical induction has fully established the following important deductions-viz., that the first of these massesthe most anterior on either side of the median line-is the olfactory ganglia, the centre in which the olfactory nerve terminates, and in connexion with the anterior extremity of the medulla oblongata.

The second pair are the sole representatives of the cerebral hemispheres, but not in their totality. The exterior covering only indicates the presence of the anterior lobes, for the interior mass, from its connexions and aspects, is the homologue of the corpus striatum.

The third are the optic lobes, the ganglionic centres of the optic nerves, which contain the homologues of the corpora quadrigemina and thalami optici of the higher vertebrata. The fourth and single mass, placed over the divergent space of the fibrous strands of the medulla oblongata forming the fourth ventricle, is the cerebellum, sometimes having rudimental lateral appendages. Now the fact is indisputable, that in the early human embryo, as in the brain of the fish, the encephalon consists of a like series of distinct ganglionic bodies, amongst which the representatives of the cerebral hemispheres are usually the smallest. We have

1st. The olfactory ganglia.

2nd. The corpora striata, covered by their lamina, which are the rudiments of the cerebral hemispheres.

3rd. The thalami optici, inclosing the third ventricle. 4th. The corpora quadrigemina, and

5th. The cerebellum.

It has been truly observed by Dr. Carpenter,

"There is no more general fact in the whole range of comparative anatomy, than that the encephalon of the vertebrata is composed of these elements, at the commencement of its development, and that the