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?