The simplest fibre is the form of forms, or that which forms the other fibres succeeding in order.
The simplest fibre by its circumflexion forms a certain perpetually spiral surface or membrane which is itself the second, the medullary or nervous fibre of the body, and is simply a little channel constructed from the simplest fibre, but together with the fluid which permeates it, constituting a fibre.
This fibre, therefore, because it descends from the prior, or is the prior fibre thus convoluted, and therefore nothing else than the simple fibre itself, flows by a spiral or perpetually circular flux.
This fibre, when it falls into the provinces of the body, again forms a kind of little gland not unlike the cortical, from which proceeds the bodily fibre, and this forms the little tunic which infolds the arterial vessels.
The fibre further descends into the greater arteries, and there also forms glands which again send out fibres from themselves, and from these is produced the muscular tunic.
Thus the nervous, glandular, tendonous, and muscular tunics, with the membranous, constitute the arteries and veins, all and each being formed of fibres.
Thus the blood vessel is produced from the simple fibre by continuous derivations.
The arterial vessel can accordingly be called the third fibre, the medullary fibre the second, and the simple fibre the first.
In this respect, also, the first fibre may be called the first vessel, then the second vessel, and finally the vessel properly so-called, or the blood vessel.
(2.) There is nothing else continuous in the whole body; or its whole form is the simple fibre alone.
For there is nothing in the medullary fibre but the simple fibre.
There is nothing in the blood vessel but the medullary fibre.
There is nothing in the whole body which is not woven together of vessels and fibres.
Even what does not so appear, — as the tendons, cartilages and bones, — yet this also experience shows to have been woven from the vessels and fibres originally.
Thus there is nothing in the entire body but simple fibre, which is its whole form.
Arguing further, if the simple fibre is an animate product from its first essence, it follows that there is nothing in the entire animal form going to form it but this essence itself.
The fluids of various kinds which are in the medullary fibres and in the blood vessels, as the serous fluids, do not constitute the form, since the forms consist of fibres; but these fluids flow within the fibres and vessels.
(3.) If that essence is the soul, it follows that this alone is what constitutes the form.
(4.) The Simple Fibre is of a celestial nature. What the Body is.
This form, because it is above other forms, cannot be touched at all by them, still less can it be hurt; it is most secure from all injury. How can a compound act upon the simples of which it is compounded? It is most remote from them, nor are they dependent upon it.
(5.) This fibre therefore is not terrestrial, as Aristotle teaches, but of a celestial nature, essence and form.
(6.) Hence it is immortal, nor can it perish, because it cannot be touched.
(7.) What is terrestrial and corporeal is not the fibre, but rather that part of the red blood and of the middle blood in the globule which serve there for an instrumental cause, in order that the first essence of the blood may descend in series by successive derivation and be in the midst of the outmost world; in a word, that it may constitute the bloods, in which, nevertheless, that celestial form reigns.
(8.) That from which the bodily blood exists is only corporeal, nor does it contribute anything to form except that it runs through these fibres and adapts them so that they may enter into forms.
(9.) This part or this corporeal is mortal and relapses to earth when the globules of blood are dissolved; but not so the fibre, which of itself passes away, while the body remains under the form of a corpse.
(11.) Concerning the Universal Circulation of the Fluid of the Body, or the Circle of Life. Concerning the Perpetual Solution and Composition of the Blood.
(12.) Concerning Diseases of the Fibres.
(13.) Concerning the Derivation of the Diseases of the Animus into the Diseases of the Body, and vice versa.
(14.) Concerning the Arachnoid Tunic.
(15.) The external organs of the senses, as the ear and the eye, are instruments of the modifications of the air and of the ether, and these modifications are the principal causes to which as to mediate organs the sensations exactly correspond.
As to the ear, this is the instrument which receives the modulations of the air; for it receives and applies to itself every form and mode of the forces flowing to it. The same is true of the eye in relation to the ether. The ear in this respect differs from a musical or acoustic instrument in that it not only receives but also sends out and further extends the sounds. So does also the eye differ from optical instruments. The eye is, indeed, like a camera obscura, which reproduces most exactly the images transmitted from the object opposed, without changing them into other forms and other colors. But in the eye these modifications do not simply pass over to the retina; the operations of the eye excite the essential determinations to acting likewise even to the least retina, from which through the optic nerve the same sight is propagated to the common sensory. Thus the sensations correspond exactly to the modifications of the organs. Likewise in taste and smell; for the external form of the parts, which is generally either round or prickly, affects the papillae of the tongue or nostrils; the organ is affected by these touches, which are innumerable, and thence a similar sense results.
(16.) The sensory fibres leading to the common sensory are exactly accommodated to the form of the modifications flowing in and affecting them; thus the sensations flow by a natural spontaneity from the circumfluent world through the fibres in the animated world even to the Soul.
In the inquiry as to what is the form of the modifications of the air and of the ether we are led to conclude from experience that there can be no other modification of form than that of the form of the parts. For the volume is composed of the parts, and if the parts are change-able a like condition ought to result in the whole volumen of what is set in motion as in the single parts, which are so many symbols of the common motion. The form of the modifications of the ether is spiral or perpetually circular, and that of the modifications of the air is simply circular; for such are the external forms of the parts, as may be demonstrated by numberless proofs. If it be asked, then, what is the form of the fluxions of the fibres, it has been proved in the treatise on the Fibres that the form of the fluxions of each compound fibre is spiral, and that the form of the fluxions of many fibres taken together is circular; thus the one form exactly corresponds to the modifications of the ether and the other to the modifications of the air. But the form of the higher ether is vortical, and this corresponds to the substantial form of the spiral glandule. Thus when modifications of the auras flow into the miniature world, or the animal system, they continue their flow in a similar nature, nor are their essential determinations changed.
(17.) The sensations are carried from the external organs to the internal organs as if from a heavy to a lighter atmosphere, or from a lower to a higher region.
Light bodies are raised from the centre toward the the surface and emerge, but those which are heavy fall to the centre and seek the bottom. So do sensations strive from the outermost to the innermost or from the lowest to the highest, while actions fall from the innermost to the outermost or from the highest to the lowest. Thus sensations may be compared to the lighter and actions to the heavier bodies.
The cortical brain holds the inmost and the highest, for to climb thither is upward, but thence toward the surface of the body is downward. That the cortex of the brain also occupies the highest region of the body may appear from the fibres themselves and their nature; the most fluid and the softest fibres are near to the cortex or to their first source; those more remote from the cortex are harder and more stationary, and as if being more compressed, when rising to a softer fibre they rise to the purer region and vice versa; which also is the reason why the nerves or the sensory fibres are soft, and the motor fibres are somewhat harder; and that the softness increases according to the ascent.
(18.) The sensations do not arrive at any special glandules or glandular congeries in the brain but at the universal cortex, so that there is not a single cortical glandule in the entire brain which does not become a participant of each sense and of its least movement, degree and difference.