If we take a general view of Swedenborg’s investigations, the outlines of which have been sketched above, a number of questions are suggested: Whence did Swedenborg secure the material for all these far-sighted statements, whence the evidence for all these discoveries? Did Swedenborg himself carry out the special investigations which must have formed the basis of his beautiful results?[52] Or was the evidence ready at hand in the literature of those days?

The answering of these questions is naturally of a certain importance in the valuation of the opinions expressed. And as several of Swedenborg’s statements concern questions which are still among the ›unsolved›, I have taken up some of these questions for examination. In this I have restricted my investigation to a confined province, and chosen one which in our own times is of great actual interest, namely, the function of the brain, and especially that of the cerebral cortex. As we have already seen, Swedenborg connected in the closest manner the soul’s activity with the cortex of the cerebrum, indeed, he localizes in detail special departments of that activity to determinate regions of the cortex; and the object of my investigation is, therefore, to endeavour to find out upon what foundations Swedenborg erected this doctrine of the centres of the psychic functions in the cortex of the cerebrum.

ON THE CENTRES OF THE VEGETATIVE FUNCTIONS.

With regard to the function of the brain, Swedenborg, in the first place, made the distinction that the cerebrum regulates the psychic, and the cerebellum the vegetative functions.

Many different opinions prevailed in Swedenborg’s time concerning this question. Some investigators considered that the vegetative as well as the psychical functions stood under the direct control of the cerebrum; others that the centres of vegetative life were separated from those of psychic life and had not, like these, their place in the cerebrum. And Swedenborg adopted the latter opinion, primarily for the following reasons:

1) Experiments on animals had brought to light the fact that respiration and the action of the heart continued for a time even after the hemispheres of the cerebrum (in dogs) had been separated from their connection with the cerebellum and medulla oblongata, indeed, even if the hemispheres of the cerebrum (in dogs) had been extirpated.[53] He was also led to the same conclusion by

2) Certain teratological and pathological anatomical experiences, which he had gathered from his studies of books. He advances cases described by Wepfer, Tyson and Ridley, Manget, Kerkring, Morgagni, and others, which showed that although the cerebrum had occasionally been entirely or in part missing in foetuses, yet these deformed foetuses could nevertheless live a shorter or longer time after birth. And in agreement with Tulpius he calls attention to the great deformation of the cerebrum in the case of hydrocephals. In close connection with this he gives accounts (from Vallisnieri and others) of extreme cases of petrifications in the brain, regarding which one must suppose that when the cerebrum gradually lost its functions and the vegetative vital functions nevertheless continued for a time, these must then have been regulated by the remaining parts of the central nervous system, that is, by the cerebellum, medulla oblongata and the spinal cord. (See Œc. R. A. I., Nos. 573, 574 et seqq.).

From these experiments and discoveries it was thus evident to Swedenborg that the centres for vegetative life are not to be sought for in the cerebrum.

As was said, he located them instead in the cerebellum, and the reason for this seems in brief to have been the following: Manget and Vieussens had described a number of experiments on animals which were said to have proved that after lesions of the cerebellum respiration and the action of the heart at once ceased.[54] The injuries in these experiments had evidently extended more deeply than the descriptions recount, by which the false conclusion in regard to the cerebellum is explained. It was probably because of such misleading experiments as these that Swedenborg’s highly esteemed contemporary, Hermann Boerhaave, (1668-1737), held the same opinion that the vegetative vital functions are regulated by the cerebellum.[55] However, the Englishman Thomas Willis, (1622-1675), had come nearer the truth, when, in a very guarded statement, he connected these functions with both the cerebellum and the medulla oblongata.[56] And when Swedenborg chose his position on the question he seems to have been influenced by both of these authors, and received the opinion that the cerebellum was the main centre of vegetative life, making, however, the important addition, that the medulla oblongata, as for that matter also the spinal cord, are secondary centres, subordinated to the cerebrum and cerebellum.[57] This addition was based upon a conclusion which Swedenborg had drawn, among other things, from the teratological and pathologic-anatomical observations and from comparative anatomy, but there is no occasion for entering into this more closely in this connection.

After Swedenborg had, however, upon the grounds alluded to, separated the centres for the vegetative life-functions from the cerebrum, there lay before him the localization of the psychical functions; and, as to them, Swedenborg located the centres of the sensory portion of the soul’s activity in the cortex of the cerebrum.[58]

ON THE CENTRES OF THE PSYCHICAL FUNCTIONS, ESPECIALLY THE SENSORY CENTRES.

That the sensory activity of the soul has its centres in the cerebrum was in Swedenborg’s time considered quite certain, but it was not so certain as to just what part of the brain it was in which the soul’s activity arose.

It is well known that the philosopher Descartes († 1650) had supposed that the glandula pinealis (pineal gland) was the seat of the soul, and that the conscious perceptions came into being in this gland and in the central ventricle of the brain, the ›third ventricle›, from which the nerves, according to his opinion, took their origin.[59]

Gradually, however, there seems to have been more and more an inclination to attribute this phase of the operation of the soul to the white medullary substance around the ventricles of the brain. And in Swedenborg’s time this opinion seems to have been the usual one. At least the matter is so presented by Hermann Boerhaave, who, as is known, in a high degree had the ear of his contemporaries.[60]

And even Haller, some twenty years after Swedenborg had written his works on the brain, was still of a similar opinion, as is evident from a quotation which I shall here bring forward, in which he emphasizes that neither perceptions nor the impulses to motion arise in the cortex of the cerebrum, but in the medullary substance: ›Non ergo in cerebri cortice sensus sedes erit, aut plena causae muscularis motus origo: eritque utraque in medulla cerebri, & cerebelli.› (Alb. v. Haller: ›Elementa physiologiae›, Lausannae, 1762, Tom. IV., p. 392). But when even Haller would not attribute the soul’s activity to the cortex, what then can have led Swedenborg to such a thought?

In order to clear up this question let us first examine the anatomical literature before Swedenborg’s time. And then we find that the Bartholins had already in a kind of way associated this branch of the soul’s activity with the cerebral cortex, because they supposed that the ›spiritus animalis›, (the ›spirits of life›), was contained in the cortex for the sensory functions, just as it was conserved in the medullary substance for the motor functions.[61]

And Thomas Willis considered that the ›spiritus animalis› was generated in the cerebral cortex, but afterwards underwent proper elaboration and distribution in the medulla of the cerebrum; and that the memory had its seat in the cerebral cortex.[62]

And Malpighi (1628-1694) had expressed the surmise, that the minute cortical elements, so particularly described by him, which correspond to what we now call the nerve-cells of the cortex, were small glands, ›glandulæ›, whose function was to prepare a substance which, conveyed through the nerves, calls forth perceptions.[63]

It had also been shown by the researches of Malpighi that these ›glandulæ› put forth a vessel-like fibre, which continued into the cerebral medulla; and that this medulla for the greater part consisted of such fibres or vessels.[64]

In how far these structures were ›fibres› or ›vessels›, and whether they proceeded from (›oriuntur›) or terminated in (›desinunt›) the small cortical elements, Malpighi leaves undecided. And when Boerhaave afterwards in his lectures on the brain describes these structures, he still depicts them as the finest tiny canals, which take up the ›spiritus animalis›, pressed into them from the cortex, and transport it down to the medulla oblongata, whence it is afterwards, by means of the nerves, distributed to the different parts of the body. This ›spiritus› Boerhaave describes as elaborated in the cortex, ›fabrica mirifica corticis praeparatus›.[65]

These observations and surmises have evidently exercised a great influence upon Swedenborg’s conception of the function of the cerebral cortex; but they alone could impossibly have aided him in reaching the enlightened standpoint at which he arrived. No, the most determining and decisive factor for him in this question evidently was a great mass of clinical and pathological observations which he had collected and synthesized, namely, symptoms of disturbances of consciousness and sensibility, which had been exhibited by such patients, who, as was shown by post mortem examination, had been injured in the cerebral cortex. And I shall later refer to some of these cases in connection with the consideration of the brain’s motor functions, because these patients nearly always also exhibited motor disturbances.

But even here I may quote some of Swedenborg’s own words, which will show what importance he attached to these testimonies: ›It is the cerebrum or the cortical substance in which the soul disposes and unfolds its purest and most simple organic forms of activity, and what the cerebrum is, appears from a change of the faculties in some diseases, as in apoplexy, epilepsy, paralysis, etc., likewise in many morbid states of the animal mind in a cerebrum wounded by various accidents;› (›The Brain›, No. 86).

And in another place he says: ›If the cerebrum is either inflamed or obstructed, or flaccid, or injured otherwise, the intellectual faculty is unsettled; as in paralysis, melancholy, in cases of delirium, in atrophy, apoplexy, in fevers, and other diseases; nay, the determination of the will also is similarly affected. For each single cortical substance contributes its share to this intellectory, that is, to this organ of the understanding, etc.› (›The Brain›, No. 104, r).

All these observations concerning the consequences of injury to the cerebral cortex—and the above-mentioned discoveries regarding the structure of the cerebral substance and the hypotheses concerning the relation of the cerebral cortex and cortical elements to the ›spiritus animalis› and the perceptions,—these clinical and anatomical experiences taken together seem to have led Swedenborg to the conviction that the activity of the soul and not least that just now in question, the sensory, had its seat in the cortex of the cerebrum.

He now enters into a detailed analysis of the course of the sensory nerves as far as they are able to be demonstrated (›in ipsius oculi luce›), and he thus follows the optic nerves to the optic thalami, and thence their radiation towards the cerebral cortex, the olfactory nerves to the corpora striata or the medulla of the centrum ovale and from there out towards its cortical surroundings, the auditory nerves to the medulla oblongata and thence up toward the cortex of the cerebrum, (›versus supremum corticem›), and in the same manner he follows the nerves of taste and touch. (See Œc. R. A. II., No. 192; and III., No. 66). He cannot now follow further the particular fibres through the medulla all the way to the cortex, of whose importance for consciousness and sensibility he became convinced through the clinical experiences, but here he must suppose a connection, and he says: ›these effects (conscious perceptions) could never be produced ... unless in every quarter there were a mutual connection and perpetual communication of the cortical substance with the medullary, as regards the fibrils ...›, (as well as a special arrangement of the cortical elements and special qualifications in them, of which more will be said later).[66]

From all this it is clear, that it was probably through a combination of clinical and anatomical experiences that Swedenborg secured the premises for his conclusions that the centre of the soul’s sensory activity is in the cortex of the cerebrum.

ON THE CENTRES OF THE MOTOR FUNCTIONS.

Swedenborg also placed the centres of the soul’s motor activity in the cerebral cortex (See Œc. R. A., No. 127, etc.).

I have not been able to find anything of this kind even hinted at in the antecedent literature. We are reminded of how preceding authors, who made an attempt at some kind of localization of the origin of motion, in most cases placed this in the medulla of the brain, as for example the Bartholins;[67] and also Boerhaave.[68] And as we have just heard, Haller still held the same view.[69] Nevertheless Swedenborg expresses his conception without the slightest hesitation, and this he did because he regarded it as resting on a sure foundation. His strongest grounds and proofs were here also derived from the clinical and pathological observations in certain cerebral diseases which had caused changes in the cortex, and in patients, who had been injured in the cerebral cortex. It was these clinical cases at which I hinted just now. And now some of these may be brought forward, for the most part as Swedenborg himself has related them—with some few abbreviations:

A female seventy years of age, who after exhibiting the premonitory symptoms of apoplexy for some months suddenly lost the power of speech, and on being conveyed to bed, lost all sensation and motion. On a post mortem examination a large cavity was found in the cortical substance of her brain (›in ejus Cerebri substantia corticali ampla cavitas reperta fuerit›, see Œc. R. A. II., No. 154). The case was taken from J. J. Wepfer’s ›Historiae Apoplecticorum› (Amsterdam, 1681, pp. 5-11).

Another case taken from Wepfer was the following: A man 50 years of age had for some weeks before his death suffered from excruciating headache, the pain of which sometimes drove him mad, so that he was not seldom unconscious of what he said and did. On examining his head after death, the whole surface of the cerebrum and cerebellum, including both the convolutions and the furrows between them, seemed to be clogged all over with a gelatinous substance, from which, when it was pricked with a lancet, genuine serum oozed out. And also the very substance of the cerebrum and cerebellum had imbibed a large quantity of serum. (Œc. R. A., loco cit. and J. J. Wepfer: Op. cit., p. 15-19).

A case from A. Pacchioni was as follows: A young man had died under symptoms of fever, severe headache and spasms, or cramp. On opening his cranium, it appeared that the firm fibrous membrane of the brain, the dura mater, was loosened from the bone on the top of the head; and here, according to the description, it had exercised a strong pressure upon the underlying portion of the brain and was tightly adherent to it. (Œc. R. A., loc. cit.)——Consequently, in the last two cases: inflammation of the membranes of the brain, or meningitis with accompanying influence upon the superficial layer of the brain, the cerebral cortex.

And still another case from Pacchioni, which was still more convincing: A youth was brought into the hospital in an almost unconscious condition, spoke incoherently, cast himself about in all directions, etc.; and furthermore——his lips were somewhat drawn over to the left side (›labris ad sinistrum paululum detractis›), thus a right-sided facial paralysis! On examination after death no injuries could be found upon the integuments of the head, nor upon the outer or inner sides of the cranium, but on the left side of the brain a depression of the cortex was discovered, occasioned by the formation of a tumor or ›bladder› on that part of the surrounding dura mater lying just over the place of depression: ›ibi depressus et durioris consistentiae cortex cerebri cavernam ostendebat vesicae congruentem.›[70]

Swedenborg brought forward still more cases, so incomplete, however, that it is not worth while to repeat them here. But he had at hand a very large number of cases, as he says: ›phalanges observationum idem testificantium› (Œc. R. A. No. 154), or, as he says in another place, so many that a bare enumeration of them would fill two whole pages (Œc. R. A. II., 154).

Swedenborg had made a specially careful study of a great many cases of apoplexy and hemiplegy, which naturally, in so far as they affected the cortex, gave him direct guidance in judging of its function. And he also understood very well how to judge at the same time with regard to the importance of bleedings in the soft membrane of the brain, the pia mater, on and between the convolutions of the brain, the ›gyri›, and the pressure that these exercise upon the cortex, and the results of prevented circulation in cases of apoplexy. For in all these cases, he says, the transmission of blood to the cortex is checked, and by this the cortex was disturbed in its function, and this was the cause of the loss of sensation and of the paralysis. (Œc. R. A., III., No. 411 and III., No. 413; see also ›The Brain›, No. 89).

But Swedenborg had also directed his attention to that method of investigation which, to the brain physiologists of the present day, is the best aid for the examination of the motor functions of the cerebral cortex, namely, experiments on animals. He quotes such experiments, in which incisions had been made into the cortex ›just to the marrow›, as it is expressed, (›usque ad substantiam medullarem› [Ridley], Œc. R. A., I., No. 505); or when the brain (in dogs) had been pierced, (Œc. R. A., II., No. 154), and how these injuries had occasioned spasms or contractions of the trunk or extremities (Ridley). He also describes such cases in which fine needles had been pierced through the dura mater and corrosive liquors introduced through the holes, with the result that severe disturbances occurred in both motility and sensibility, and also how through such injuries muscular contractions had been provoked, by which it was sometimes observed that with certain stimuli the contractions first occurred in certain groups of muscles (for example, in the head or neck) and afterwards spread to the other parts of the body. (Baglivi ›The Brain›, No. 20).

As will be seen, these experiments were no ›precision-investigations›; and the same may be said of the clinical and pathological ones. And this may be the more easily understood, when we consider that in those times so much interest was not attached to such special observations of pathological changes in the cerebral cortex; for this was then regarded only as a gland, a secreting organ or reservoir for the ›spiritus animalis›. These observations were therefore made more as it were in passing. The same is also true of the experimental investigations on animals, quoted above. These were in reality made not in order to investigate any function of the cortex, but for other purposes, namely, in order to search out the causes of the pulsations of the brain, or the qualities and functions of the dura mater, etc.

Yet, as we shall see later on, some of the cases, in the original descriptions, really contain statements somewhat more exact and of greater interest even for the theory of cortical localizations, than those which Swedenborg quoted; but he seems to have here adduced no more than what had reference to the cortex regarded as a whole, and which showed what great changes in both the power of sensation and motion injuries in the cortex could produce. If we take this into consideration, and if we synthesize all these experiences, and add to this the increased knowledge concerning the minute structure of the brain, which had been produced especially by Malpighi’s discoveries, we must admit that Swedenborg had good reasons for his view that the soul’s activity had its seat in the cortex of the cerebrum.

THE DOCTRINE OF LOCALIZATIONS.

But Swedenborg, as is well known, did not stop here. The cerebral cortex certainly constituted a whole which transformed the sensations into thoughts and determinations, but all the regions of the cortex were not of the same degree: some ruled the higher, others the lower functions, thus also containing subdivisions, in some of which the sense-impressions were received, in others from which the motor impulses proceeded. (See ›The Brain›, Nos. 66, 68, 71, 88, 98, 100, 102, etc.).

This conception of the brain appears at first glance as very modern. But upon searching the literature before Swedenborg’s time one finds that the thought was not so entirely original. New was the thought of attributing the psychical functions to the cortex, new also was the attempt to accurately determine upon the place where the different functions originate; but the idea of localization itself is found again in the literature which Swedenborg already had at his disposal.

Boerhaave, for instance, says, in his ›Institutiones medicæ›, when speaking of the sensations, that they give rise to different perceptions, partly owing to the differing species and nature of the outer objects, and partly to the different natures of the sense-organ and the affected nerve, but partly also to the different regions in the cerebral medulla from which the nerve proceeds. Thus we have here a kind of localization to a special region of the brain, although in its medulla.[71] And still more clearly does Boerhaave express the same idea in his ›Prælectiones academicae,› where he says: ›In the ’Sensorium commune’ there are regions locally distinguished for the different senses, just as every sense has its own special sense-organ.›[72]

And before Boerhaave the philosopher Descartes had expressed an idea concerning a certain form of localization of the various elements of psychic activity. For he supposed that the images of sensation and the images of the memory, etc., which the soul perceives, arise on those places on the walls of the brain’s central ventricle, where, according to his opinion, the various nerves originate. In a similar way he also imagined the origin of motility localized. (R. Descartes: ›De homine›, publ. by F. Schuyl, Ludg. Bat., 1662).

We here reproduce some illustrations from the work of Descartes just mentioned, which are designed to show how he thought that the images of sensation arise. — — See the figures 1, 2, 3.

We thus see that the idea of localization itself was not altogether new. But how did Swedenborg ultimate and develope it?

With regard to function Swedenborg divided the hemispheres of the cerebrum into two parts: one anterior region and one posterior, conceiving the fissure of Sylvius as the dividing boundary between them. (›The Brain›, Nos. 16, 88, 91).

To the anterior region he attributed the actual operation of the soul, while he supposed that the posterior region was chiefly engaged in the animation of the blood. He adds, however, ›it cannot be denied that sensations reach even the posterior region of the brain, yet our mind does not become conscious of them to the same degree as it does in the anterior region› (›The Brain›, No. 71).

In this anterior region of the cerebrum he distinguished three lobes, or so called ›curiae›, the first one highest up, ›in the crown›, a middle one below it, and a third one lowest down, i. e., nearest to the fissure of Sylvius.[73] In these three lobes the actual psychic life is developed, and that so much the more clearly and perfectly, the higher up in the region these intricate processes occur. It is here that perceptions, thoughts, judgments, conclusions, come into being; it is from here that ultimately will and determination issue. (See ›The Brain›, Nos. 12, 66, 71, 88, 98, 100, 102).

As regards the sensory part of the psychic activity, Swedenborg does not make any attempt at a detailed localization; but as regards the motor functions he arranges their centres within the above-mentioned regions as follows: ›The muscles and actions which are in the ultimates of the body or in the soles of the feet seem to depend more immediately upon the highest parts (of the brain), upon the middle lobe the muscles which belong to the abdomen and thorax, and upon the third lobe those which belong to the face and head;› and he adds, ›for they seem to correspond to one another in an inverse ratio› (›The Brain›, No. 68).

Whence did Swedenborg get all this? Whence the whole of this doctrine of localizations? In his first great anatomical work, ›Œconomia Regni Animalis›, nothing is said about it; first in his last anatomical work, ›De Cerebro›, is it advanced, and then — — — quite finished! One is at first glance tempted to think that he had succeeded in finding some new clinical experiences, upon which he could found this doctrine. For he had not even finished the account of the function of the brain’s anterior region, before interjecting: ›Therefore, if this portion (the anterior region) of the cerebrum is wounded, then the internal senses—imagination, memory, thought—suffer; the very will is weakened, and the power of its determination blunted. This is not the case if the injury is in the back part of the cerebrum› (›The Brain›, No. 88). But afterwards he does not bring forward (in ›De Cerebro›) any observations which could serve as proof with regard to this. And if one examines the cases he has referred to in his preceding works, one cannot possibly arrive at the localization of the psychic functions which he has here (in ›De Cerebro›) sketched; for the evidence concerning the position of the injuries in the cortex are entirely too scanty and incomplete. But if we consult the original descriptions, we find there many other and more particular data than those quoted by Swedenborg when he was only concerned in explaining the function of the cortex as a whole. Wepfer, for instance, reports in his ›Historiæ apoplecticorum› concerning the woman seventy years of age, who suddenly lost the power of speech, that the cavity, filled with blood, which was found in the cortex at the autopsy, was located in the right hemisphere, just behind the forehead (›ad frontem fere antrorsum›), and that it extended rather far both backwards and upwards; even measurements were given (length 8, breadth 4, depth about 2 uncias). It was also stated that the blood-vessels whose bursting caused bleeding belonged to the antero-lateral branches of the carotid artery in the brain. It is also mentioned that no changes were found in the left hemisphere of the brain; and from the clinical account it appears that even after the stroke the woman was able to move the extremities of the right side.[74] — — — All this indicates quite evidently that the lesion of the cortex was situated in the anterior region of the brain!

And Pacchioni reports concerning the youth, who was afflicted with the right-sided facial paralysis, that even the extremities of the right side were somewhat paralysed, and that the cyst, which at the post mortem examination was found on the left hemisphere, extended from the crown to the region of the temple (›a capitis vertice in temporalem regionem›).[75] Thus this case also furnishes an unmistakable indication that the cortical lesion was situated in the anterior region of the brain.

It seems strange that Swedenborg did not here supply an account of these interesting and convincing cases, which he nevertheless, as we have seen, was well acquainted with. For his habit is to furnish the chapters of his works with an introduction in which he reports, often in very detailed form, the statements of the authors upon which he bases his conclusions. Since in the present case such an account is lacking, this may depend: either upon the fact that this last anatomical work of Swedenborg, ›De Cerebro›, was not quite completed and finally edited for the press, or thereon that Dr. Rudolf Tafel, who edited the translation which is now accessible in print, excluded it. For Dr. Tafel says in a note that the introduction to the chapter in question would be introduced into Part II., chapters 1 and 2, but—Part II. was never printed! Since, however, the Royal Swedish Academy of Sciences will publish ›De Cerebro› in its edition of Swedenborg’s Scientific works, this question will no doubt be cleared up. But this much is quite clear from what has already been adduced, that the cases of paralysis which Swedenborg previously quoted in a brief form are in the original descriptions reported so completely and in such detail that one can without the least doubt localize the cortical lesions reported in those cases in the anterior (superior) region of the cerebrum.

We now pass to an examination of the anatomical literature to which Swedenborg had access. And, as we shall find, we can here see whence Swedenborg derived material for his detailed doctrine concerning the function of the brain’s anterior region. This becomes evident on comparing Swedenborg’s mode of thinking of the brain’s psychical activity with the descriptions of preceding authors in anatomy.

The group of nuclei, ›corpus striatum›, in the cerebrum had been an object of special interest for preceding authors.

The Englishman, Thomas Willis, had for example in his ›Cerebri anatome› (published in 1667) portrayed them as a kind of junction, ›internodes›, by which the cerebrum coheres with the medulla oblongata; and he pays special attention to it on account of its peculiar structure (›The Brain›, No. 476); and he is said even to have attributed to them the ›Sens commun›.[76]

And the professor in Montpellier, Raimond Vieussens, had given in his ›Neurographia universalis› (published in 1685) a very exact description of the ›corpus striatum›, (not only of its ›superior nuclei›: ›Corp. striat. sup. ant.› = Nucleus caudatus and ›Corp. striat. sup. post.› = ›Thalamus opticus›, but also of its lower lateral nucleus = ›Nucleus lentiformis›) as also of the mighty medullary tract of nerve fibres, i. e., ›capsula interna›, which passes through the same, and which on the one hand is distributed to the brain, especially to its anterior (superior) region, and on the other hand by means of the nerves radiates into the various parts of the body.

(In order to facilitate orientation we may refer to C. Toldt: ›Anatomischer Atlas›, 1899, 8 Lieferung, Fig. 92: ›Querschnitt des verlängerten Markes und der Gehirnstiele. Verlauf der Pyramidenbahn von der Pyramidenkreuzung an durch die Pyramide, die Brücke und die Basis des Grosshirnstiels in die innere Kapsel, woselbst sie in den Stiel des Stabkranzes, Pedunculus coronæ radiatæ, eingeht.›)

Swedenborg, who had studied and often quoted both Willis and Vieussens, likewise attributed a very great significance to the corpus striatum. All the sensory impressions pass through it to the brain, and all the voluntary impulses to motion pass out by the same path. (›The Brain›, No. 67). ›It is›, says he in his figurative way, ›in a certain sense, the Mercury of the Olympus; it announces to the soul what is happening to the body, and it bears the mandates of the soul to the body› (›The Brain›, No. 67).

And as the corpus striatum lay most immediately under the anterior (superior) region of the brain, and was in close connection with it, so the sensory impressions would for the most part pass to this region, and the voluntary impulses to motion would likewise proceed from it (›The Brain›, Nos. 66, 67).

The same Vieussens had furnished a very detailed description of the passage of the nerve tracts in question, which pass through the corpus striatum and capsula interna, and had followed them both upwards towards the hemispheres of the brain and downwards towards the spinal cord. When he followed them upwards, he found that they formed three regions in the ›centrum ovale›: the regio superna, highest up nearest the crown, the regio media, in the middle, and the regio infima, lowest down, and consequently nearest the fissure of Sylvius. (R. Vieussens: ›Neurographia univ.›, pp. 115 and 117).

In these regions of the cerebral medulla, especially in the highest, Vieussens considered that the soul’s activity had its seat: with the help of ›spiritus animalis› the soul here had an opportunity of receiving the sensory impressions, and in the fine and finest nerve fibres there were here formed sensory images, conceptions, (Op. cit. p. 129), here the memory images were preserved, (Op. cit. p. 135), and here the faculty of judgment had its seat, (Op. cit. p. 137), etc.

In these regions, especially in the highest, the will also had its seat and origin, and at its command the ›spiritus animalis› streamed out through the nerves, thus conveying the impulses to motion to the various muscles of the body. (Op. cit. pp. 122, 123, 188, et seqq.).

For Swedenborg, who had arrived at certainty with regard to the seat of the soul’s activity in the cerebral cortex, and not in the cerebral medulla!, and who through Malpighi and others had been led to see that the fibres of the cerebral medulla were continuations of the processes of the cortical elements,—for Swedenborg it naturally lay very near at hand to follow the fibres of the three regions of Vieussens out to the cortical substance on the surface of the brain; and so Swedenborg has his three cortical lobes! And to them, especially to the highest, he could now attribute the source of the soul’s life.

When Vieussens followed the nerve tracts of the corpora striata and capsula interna downwards, he found:

that the fibres of the uppermost region led down to the posterior region of the spinal cord; (›ad posticam spinalis medullæ regionem›);[77]

that the fibres of the middle region, which were especially coarse and traversed the capsula interna and pons, forming thick tracts, could be clearly followed down into the anterior portion of the spinal cord, (›in anticam spinalis medullæ partem›), where they came into connection with the anterior origins of the spinal nerves, (›ad antica nervorum spinalium principia›), also paying, on their passing through the medulla oblongata, ›necessary tribute›, (›necessarium vectigal›), as it is expressed, to certain of its nerves;[78]——See the figure 4!——

that the fibres of the lowest region were distributed to certain nerves, which proceed from the medulla oblongata, and to some of the anterior origins of the spinal nerves (›quædam illius pars ad quosdam e Medulla oblongata prodeuntes, altera vero ad antica nervorum spinalium principia›).[79]

In Swedenborg’s time it was, however, known that the muscles which produce the movements of the head and face receive their nerves just from the medulla oblongata and the uppermost part of the spinal cord; and it therefore lay near at hand for Swedenborg, when he saw that paralyses arose when certain cortical regions were destroyed, to draw the conclusion, that the muscles and movements which belong to the face and head, depend more immediately upon the lowest region of the third lobe of the cerebral cortex.

And as it was also known that the muscles of the thorax and abdomen receive their nerves from the superior portion of the spinal cord, whither just the tracts of coarse fibres from the middle region of the brain could be followed, (see figure 4), so Swedenborg could likewise draw the conclusion from this that the muscles and movements which belong to the thorax and abdomen depend more immediately upon the middle region or lobe.

It might now appear tempting to continue the conclusion by connecting the remaining highest lobe and the lower extremity. But probably Swedenborg did not consider that he had sufficient ground for this. The description by Vieussens did not here furnish any suitable guidance, for it was possible that the coarse fibres of the middle region continued so far down into the spinal cord that they could innervate not only the muscles of the abdomen but also those of the lower extremity. For this reason Swedenborg refrains from localizing exactly the centre of motion of the lower extremity and contents himself with stating in general terms only that this centre might lie above that of the abdomen. He therefore says: ›the order seems to be so disposed that——the muscles and actions, which are in the ultimates of the body, or in the soles of the feet, depend more immediately upon the highest parts (of the brain)›, whereas concerning the thorax and abdomen he says that they depend upon the middle lobe, and of the head that it depends upon the third lobe. (›The Brain›, No. 68). I believe that this is the reason why Swedenborg’s doctrine of localizations as concerns the motor centre of the lower extremity is expressed in such vague terms.

From a comparison of these descriptions by Swedenborg and Vieussens we have found that there are such considerable similarities between them that they in many respects agree point for point. And it therefore seems to me rather probable that Swedenborg derived his conception of the more detailed localization of the soul’s activity from the descriptions of Vieussens.

THE ›CEREBELLULAR THEORY›.

But Swedenborg was not satisfied with knowing only that the psychical functions arise within certain regions of the cortex of the large anterior region of the cerebrum: but he continued his search for their inmost origin, and thus he came to the conviction that the psychical processes in reality result from the joint work which is performed by the minute cortical elements, which Swedenborg called ›Sphaerulae› or ›Cerebellula›, that is, the same bodies which we now call the cortical nerve-cells. These were the units of which the brain was in reality composed and out of which its actual esse was derived. (See ›The Brain›, No. 34). It was to these ›Cerebellula› that the sensory impressions went, and in these they were perceived and brought to consciousness; it was in these that conceptions, thoughts, judgments, conclusions, came into being. (Œc. R. A. II., No. 191, and ›The Brain›, No. 98). And this was possible because there were as many kinds of ›Cerebellula› as there were kinds of sensory impressions, and that these ›Cerebellula› were connected together into groups with different subdivisions. (Œc. R. A. II., No. 193; VII., chap. XX.). It was also from the ›Cerebellula› of the cortex that the determinations and impulses to the various movements of the body emanated. (›The Brain›, No. 99). And this was possible because the ›Cerebellula› cohered each with its own nerve-fibril, which in their turn innervated the muscle fibre, and that the ›Cerebellula› were arranged into groups, these into greater groups, these into convolutions (gyri), etc., corresponding to muscle fibres, muscles, groups of muscles, etc. (Œc. R. A. II., Nos. 146, 156, and ›The Brain›, No. 99). And it is in this connection that Swedenborg refers to experiments on animals by which it might be shown which gyre or part of convolution it is, which answers to this or that muscle in the body.[80]

How Swedenborg was able to come to this modern conception ought not to be so exceedingly difficult to understand if we summarize what was already known at that time about these cortical elements and add thereto the conclusions as to the functions of the cortex to which Swedenborg had already come.

In Swedenborg’s time the conception of Hippocrates of the brain as a gland was still generally received. In this one had, however, as Malpighi says, ›since the time of Piccolomineus› learned to distinguish between an outer, greyish layer, ›cerebral cortex›, and an inner, more pure white mass, the ›cerebral medulla›.[81]

Through the microscopic investigations of Leeuwenhoek (1632-1723) it had further been discovered that the substance of the brain (especially of the cortex) contained, besides a great mass of blood-vessels and very fine fibres, a numberless mass of peculiar small bodies of varying size, by him called ›globuli›, connected with the vessels and fibres. (See Œc. R. A. II., Nos. 71-75, 112, etc.).

Malpighi, (1628-1694), had closely examined these ›globuli› and described them as small oval or polygonal ›glands›, which were closely surrounded by blood-vessels, and in their inner central ends sent forth processes forming vessel-like fibres which continued into the cerebral medulla.[82]

As these fibres or vessels formed small clusters, the little glands hanging on their extreme ends, like ›dates on their stems›, as Malpighi expresses it, thus formed small groups.

Within these groups the cortical elements were, however, well isolated from each other by clefts, which indeed sometimes were very small, but could nevertheless be plainly demonstrated with the aid of colouring matter.[83]

The cortical elements taken together formed the winding groups which on the surface of the brain gave rise to the so called gyres.[84]

The profusion of blood-vessels, as was said, Leeuwenhoek and Malpighi had already described as being very great, but Ruysch (1638-1731) had afterwards by his famous vascular injections found it to be so great that he would not call the cortex a glandular but actually a ›vascular› tissue. (Œc. R. A., II., No. 86). Because of the enormous wealth of blood-vessels there was thus carried to the cortical substance, especially to the little follicles, a plenteous quantity of blood, and from this, according to the opinion of that day, the most subtile components of the blood could pass to the cortical elements and thereby be transformed into ›spiritus animalis›. And finally, the Italians Bellini, (1643-1704), and Zambeccari had shown by their analyses that the juice of the brain possessed a highly subtile composition, above all a great volatility and lightness, and was exceedingly mobile. (See Œc. R. A. II., Nos. 88, 96, 119). All this Swedenborg has himself quoted in his works.

On the basis of these and some other anatomical and physiological data, in conjunction with a number of clinical and experimental observations, Swedenborg, as we have before seen, came to the conclusion that it is in the cortex that the soul’s activity comes into being; but at the same time he concluded that, strictly speaking, the cortical elements were the real work-shops. For he reasoned in the following manner: When the sensory impressions enter the brain, they certainly proceed no further than to the ›Sphaerulae› of the cortex, since these constitute the beginnings of the nerve and medullary fibres: were they to go further, for instance to the small arteries which surround the cortical elements, or to the membranes of the brain, then they would overstep the boundary, as he says, and leave the actual centre and go out to the more peripheral parts.[85]

Swedenborg consequently here followed the same line of thought as his predecessors. Descartes supposed that the nerves originated from the wall of the central ventricle of the brain and therefore located the images of sensory impressions, etc., there. Vieussens and others thought that the nerves originate from the centrum ovale, and thus he placed the psychic activity there. And Swedenborg now proceeded in a similar manner when he attributed the psycho-sensory operations to the ›Cerebellula›. And what other parts of the cortex were better fitted to perform the demanding and ever-shifting psychical labour than the ›Cerebellula›, to which the life-giving powers of the blood were so plentifully admitted, and in which, according to the testimony of many, the highly subtile nervous fluid was created, whose office it was to communicate the rapid and shifting utterances of the soul’s life!

Swedenborg’s predecessors had thought that the distinctions between the sensory impressions depended partly upon what kind of nerve was affected, and Vieussens had located the images of perception and memory in the nerve-tubes in the centrum ovale, which had the finest caliber. What, then, was more natural than that Swedenborg should now locate these images in the ›Cerebellula› of the cortex? For what substance of the cortex was better fitted, a more suitable medium to comprehend and distinguish the innumerable shades of the impressions than these myriads of ›Cerebellula›—of different sizes, forms and consistency, etc., which were connected each with its own special nerve-fibril and so well distinguished from their neighbors! And at the same time they were connected with the other ›Cerebellula› into groups of different kinds, by which the psychical elaboration of the impressions was made possible.

On similar grounds Swedenborg supposed that the psycho-motor labour was performed by the ›Cerebellula›, from which the nerves derived their origin. And here we may recall that Vieussens had already connected certain groups of nerves with certain bundles of medullary fibres, and that Malpighi had shown how bundles of fibres of the cerebral medulla corresponded to smaller and larger groups of cortical elements, each one of which, hanging by its fibre, formed the different gyres of the brain. If we consider this, then we can easily understand how Swedenborg, with his view of the cortex, could divine the correspondence between the components of the convolutions and the muscles.

It is interesting to here follow him in his line of thought and to see how well he understood how to combine his anatomical and clinical experiences: With the magnifying glass one can see how the nerve-fibres spring forth from the cortical substance like a brook from its source; if now the cortical substance be injured (as in the case of certain brain diseases, and which one may clearly see upon autopsy), then the injury is spread through the nerves connected with the cortex and at last all the way down to the muscles, and that, he thought, explained the motor disturbances.[86] And further ... when one or several of the ›Cerebellula› of the cortex are destroyed, then the damage is spread more immediately only to their proper nerves and muscles.[87]

In this manner did Swedenborg synthesize his anatomical, pathological-anatomical and clinical experiences and extracted from them his conclusions, and by them he arrived at essentially the same conception, as our times, of the principles of the nervous system, its cellular structure. He did not indeed employ the same nomenclature for the nerve-cells and their long processes, as we do; but the matter itself: the nature of the nerve-cells as elementary organs of the nervous system, the intimate connection between the nerve and its cell-body, indeed even its dependence upon it in regard to nourishment, etc., he was able to clearly grasp in this way,—and this more than a century before our modern theory of these relationships, the ›neurone-theory› saw the light.

CONCLUDING SUMMARY.

I hereby conclude my presentation of the grounds upon which Swedenborg appears to have founded his doctrine of the cerebral cortex as the seat of the soul’s activity.

I. It has here been my endeavour to show, that his first general statement that the centres of the psychical functions are to be found in the cortex was a conclusion, which he derived from three premises, secured in different ways:

The 1st premise was a conclusion drawn from the clinical observations, post mortem discoveries and results obtained from experiments on animals, which he had collected from literature;

The 2nd premise was a summing up of the comparatively recent discoveries in microscopic cerebral anatomy, and

The 3rd was an hypothesis, concerning the continuous connection between the cortical elements and the fibres of the cerebral medulla, by which an easy communication was established between those elements and the distributions of the nerves in the various parts of the body. In his conclusions from these premises Swedenborg had some guidance in preceding authors, who placed at least the sensory function in a certain connection with the cortical substance.

II. His second statements, his essential doctrine of localization, showed in many points a great agreement with that presented by Vieussens, but also contained important differences, which partly rested upon the conclusion to which Swedenborg had previously come, concerning the importance of the cortex for the psychic life, partly depended upon the new point of view concerning the correspondence of the cerebral regions to those of the body, to which he had arrived in his work supported by clinical results. The detailed doctrine of localizations seems to have been constructed with the assistance of Vieussens’ detailed statements concerning the connection of the nerves with the various regions of the cerebral medulla.

III. His third statement, his—so to speak, ›Cerebellular theory›, that the ›Cerebellula› were the units of which the brain was in reality composed, and that the function of the cortex was essentially the summing up of the activity of the ›Cerebellula›, and that the ›Cerebellula› were connected with one another into various kinds of groups, corresponding to the various kinds of perceptions and to the different movements of the body, etc., this was grounded in part upon the discoveries of Malpighi and others and their detailed descriptions of the structure and situation of the cortical elements and their connection with each other, in part upon Swedenborg’s clinical experiences and his own previously drawn conclusions, which be further followed up.

The first two statements have in our time been embraced with the liveliest interest and essentially corroborated. And as concerns the third, the same applies in part; but how great the validity of this statement is, it is for the future to decide.

Consequently Swedenborg arrived at almost the same result as that to which our own day has attained, although in a partly different manner. Our times have had the assistance of exact methods of investigation and of a most highly developed technique. In Swedenborg’s time the research method of microscopical anatomy and experimental physiology were yet in their cradle; and the two branches of science, medicine and pathology, which afterwards with the greatest interest have taken part in the investigation of the function of the cortex, had then hardly as yet turned their attention thither. As to how Swedenborg nevertheless succeeded in winning such rich and beautiful results in this field, and how well he employed the widely spread literature in question, I have attempted to show in this my presentation by tracing his path through the folios of the old authors and indicating the places where he gathered the material for his doctrinal structure and the premises for his conclusions. Finally, however, it should be emphasized that, when Swedenborg collected his facts from the many separated fields of literature, he found them not at all presented in the large works as important ›chief subjects›, or even as lying plainly at hand. No, he was often, so to say, obliged to dig out his material from a chaos of erroneous observations, false interpretations and curious conceptions; and afterwards he had to still further sift and elaborate it, before he could draw his conclusions out of it.

In view of all this one must say that it was in truth a work of genius to search out of such a chaos the guiding threads which were concealed within it, and that, in spite of their imperfection in many points, nevertheless to be able to find so much of the truth!