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