Swedenborg himself, however, was not satisfied with the result, but acknowledges that he had been too hasty, when, after having in reality thoroughly considered only the blood and brain, he entered immediately upon the search for the soul. He therefore says in the preface to the next work: ›I am now determined to allow myself no respite, until I have run through the whole field to the very goal—until I have traversed the universal animal kingdom to the soul (usque ad animam). Thus I hope, that by bending my course inward continually, I shall open all the doors that lead to her, and at length contemplate the soul herself: by the divine permission.›
It is grand to see the indomitable energy and zeal for investigation in this man of 53 years!
He was now obliged to extend considerably the field of his investigations—thereby to come to still more thorough insight into the conditions of the soul’s life, and afterwards, as he says, ›in his analytical way to be able to work himself up from the lower to the higher›, to find the way from phenomena and facts to causes and the final principles of the organism’s intricate mechanism.
Three years later he has ready the first two volumes of his new work, and the following year, 1745, a third volume. This work is the ›Regnum Animale›, (The Soul’s Kingdom). It is constructed upon a very grand plan, comprising not less than 17 parts. Of these, however, only the three mentioned above issued from the press, and they treat of the organs of the chest, abdomen, and skin, and of the senses of touch and taste.[50] Professor Immanuel Tafel (Tübingen) in the middle of the 19th century afterwards published two more volumes of the manuscript. The first of these, Pars quarta, treats chiefly of the senses of smell, hearing and sight and the higher degrees of the soul’s activity; and the other, Pars septima, treats of the soul.[50 b]
But simultaneously with the work in question Swedenborg wrote still another, namely, the great work on the brain, ›De Cerebro›.—In these works Swedenborg reached the summit of his scientific career, and they afterwards served as the foundation of the religious edifice to which he devoted the remainder of his life.
The ›De Cerebro› of Swedenborg, just referred to, is a rather large work which treats of the brain from the anatomical, physiological, and philosophical standpoints. This work left by Swedenborg in Ms., has appeared in print only in part, namely, in the English translation by Dr. Rudolf Tafel, published in London in two volumes, 1882 and 1887, and entitled ›The Brain›. Although this edition comprises, as was said, only a portion of the whole work, it treats of both the cerebrum, cerebellum and medulla oblongata, as well as of the cranium and the membranes of the brain, but chiefly only in so far as their structure and function regard the activity of the soul. Without doubt Swedenborg’s main interest here centred on this subject, and therefore I shall give some intimations concerning how deeply Swedenborg has succeeded in seeing into the function of the cerebrum as the organ of the soul’s life.
Swedenborg divided each hemisphere of the brain into an anterior and a posterior region, separated from one another by the fissure of Sylvius. Now, in the anterior region he located the essential activity of the soul, while as regards the posterior region, he supposed that it was chiefly active in animating the blood (›The Brain›, No. 71). In the anterior region he furthermore distinguished three lobes, or, as he called them, ›curiae›, in which the soul resided and exercised its functions (›The Brain›, No. 88). He does not define the boundaries of the lobes, but distinguishes them by saying that the soul’s activity in the highest lobe attains to the highest degree of clarity and perfection, while in the inferior lobes, the middle and the lowest, the soul’s activity successively decreases in sharpness and intensity! (›The Brain›, Nos. 66, 88). In these lobes or curiae the essential psychic life also has its rise; here observations, thoughts, judgments, conclusions come into being, yea, even determinations and the utterances of the will proceed thence. Here consequently is the source of both the sensory and the motor functions of the soul (›The Brain›, Nos. 88, 100).
As we have seen, Swedenborg had already shown, in ›Œconomia Regni Animalis›, not only that it is in the cortex, but just in the cortical elements, the ›Cerebellula›, that the brain’s psychic function is performed. Swedenborg emphasizes the same idea in ›De Cerebro›, and declares that these ›Cerebellula› are the units of which the brain is constructed, and from which its essential nature is derived (›The Brain›, No. 34).
As in the ›Œconomia Regni Animalis›, so in ›De Cerebro›, he also refers to the arrangement into different groups, which is so important for the function of the cortical elements or ›Cerebellula›, and with respect to this he now makes a new statement, which is of such a nature as necessarily to excite amazement: he sets forth the most essential part of the modern theory of localizations. Word for word this statement reads as follows: ›The muscles and actions which are in the ultimates of the body, or the soles of the feet, seem to depend more immediately upon the highest parts (of the anterior region of the brain)[51], the muscles which belong to the abdomen and thorax upon the middle lobe, those which belong to the face and head upon the third lobe; for they (the muscles of the body and the lobes of the brain)[51] seem to correspond to one another in inverse order›. (See ›The Brain›, No. 68).—Thus, the essential features of the modern doctrine concerning the relative positions of the motor centres in the cortex of the brain, that doctrine into which we have obtained an insight first after much comprehensive and complicated labour during the last century!
I shall no longer at this point continue the discussion of this work. What I have brought forward may suffice to indicate the character of Swedenborg’s investigation and the statements and discoveries based thereon. By his works on the brain Swedenborg reached the summit of his Scientific activity, but also its conclusion. He now passes over to the transcendental field. With the limits which we have set for our examination, we must, however, refrain from following the energetic investigator in his continued search for truth.