The same thing is imaged in the lungs, whose arteries and veins correspond to the affections of love, and whose respirations correspond to the perceptions and thoughts of the understanding, as has been said above. That the heart's blood is purified of undigested matters in the lungs, and nourishes itself with suitable food from the inhaled air, is evident from much observation. (1) That the blood is purified of undigested matter in the lungs, is evident not only from the influent blood, which is venous, and therefore filled with the chyle collected from food and drink, but also from the moisture of the outgoing breath and from its odor as perceived by others, as well as from the diminished quantity of the blood flowing back into the left ventricle of the heart. (2) That the blood nourishes itself with suitable food from the inhaled air is evident from the immense volumes of odors and exhalations continually flowing forth from fields, gardens, and woods; from the immense supply of salts of various kinds in the water that rises from the ground and from rivers and ponds, and from the immense quantity of exhalations and effluvia from human beings and animals with which the air is impregnated. That these things flow into the lungs with the inhaled air is undeniable: it is therefore undeniable also that from them the blood draws such things as are useful to it; and such things are useful as correspond to the affections of its love. For this reason there are, in the vesicles or innermost recesses of the lungs, little veins in great abundance with tiny mouths that absorb these suitable matters; consequently, the blood that flows back into the left ventricle of the heart is changed into arterial blood of brilliant hue. These facts prove that the blood purifies itself of heterogeneous things and nourishes itself with homogeneous things. That the blood in the lungs purifies and nourishes itself correspondently to the affections of the mind is as yet unknown; but in the spiritual world it is very well known, for angels in the heavens find delight only in the odors that correspond to the love of their wisdom, while the spirits in hell find delight only in the odors that correspond to a love opposed to wisdom; these are foul odors, but the former are fragrant. It follows that men in the world impregnate their blood with similar things according to correspondence with the affections of their love; for what the spirit of a man loves, his blood according to correspondence craves and by respiration attracts. From this correspondence it results that man as regards his love is purified if he loves wisdom, and is defiled if he does not love it. Moreover, all purification of man is effected by means of the truths of wisdom, and all pollution of man is effected by means of falsities that are opposite to the truths of wisdom. [DLW420]
That these three from the will's love follow in order in the understanding can, indeed, be comprehended by the rational man but yet cannot be clearly seen and thus so proved as to command belief. But as love that is of the will acts as one with the heart by correspondence, and wisdom that is of the understanding acts as one with the lungs (as has been shown above) therefore what has been said (in n. 404) about affection for truth, perception of truth, and thought, can nowhere be more clearly seen and proved than in the lungs and the mechanism thereof. These, therefore, shall be briefly described. After birth, the heart discharges the blood from its right ventricle into the lungs; and after passing through these it is emptied into the left ventricle: thus the heart opens the lungs. This it does through the pulmonary arteries and veins. The lungs have bronchial tubes which ramify, and at length end in air-cells, into which the lungs admit the air, and thus respire. Around the bronchial tubes and their ramifications there are also arteries and veins called the bronchial, arising from the vena azygos or vena cava, and from the aorta. These arteries and veins are distinct from the pulmonary arteries and veins. From this it is evident that the blood flows into the lungs by two ways, and flows out from them by two ways. This enables the lungs to respire non-synchronously with the heart. That the alternate movements of the heart and the alternate movements of the lungs do not act as one is well known. Now, inasmuch as there is a correspondence of the heart and lungs with the will and understanding (as shown above), and inasmuch as conjunction by correspondence is of such a nature that as one acts so does the other, it can be seen by the flow of the blood out of the heart into the lungs how the will flows into the understanding, and produces the results mentioned just above (n. 404) respecting affection for and perception of truth, and respecting thought. By correspondence this and many other things relating to the subject, which cannot be explained in a few words, have been disclosed to me. Whereas love or the will corresponds to the heart, and wisdom or the understanding to the lungs, it follows that the blood vessels of the heart in the lungs correspond to affections for truth, and the ramifications of the bronchia of the lungs to perceptions and thoughts from those affections. Whoever will trace out all the tissues of the lungs from these origins, and disclose the analogy with the love of the will and the wisdom of the understanding, will be able to see in a kind of image the things mentioned above (n. 404), and thereby attain to a confirmed belief. But since a few only are familiar with the anatomical details respecting the heart and lungs, and since confirming a thing by what is unfamiliar induces obscurity, I omit further demonstration of the analogy. [DLW405]
In the other life there are very many methods of agitation, and also very many methods of inaugurations into circles. The purifying in the body of the blood, as well as of the serum or lymph, and also of the chyle, represents these agitations, which are effected also by various castigations; and the subsequent introducing into use of these fluids represents the inaugurations into circles. It is a very common thing in the other life for spirits, after undergoing agitation, to be let into a tranquil and delightful state, thus into the societies into which they are to be inaugurated, and to which they are to be joined.
 That the castigation and purifying of the blood, serum, and chyle, and of the food in the stomach, correspond to such things in the spiritual world, cannot but seem strange to those who think of nothing else in natural things than what is natural, and especially to those who believe in nothing else, thus denying that there is or can be anything spiritual within natural things that acts and rules; when yet the truth is that in all and each of the things in nature and her three kingdoms there is an inward active force from the spiritual world; and unless this were so, nothing whatever in the natural world could act as cause and effect, and consequently nothing could be produced. That which is within natural things from the spiritual world is called a force implanted from the first creation; whereas it is an endeavor, on the cessation of which, action or motion ceases. Hence it is that the universal visible world is a theater representative of the spiritual world.
 The case herein is like that of the motion of the muscles from which is action; unless there were in this motion an endeavor from man's thought and will it would cease in a moment; for it is according to laws known in the learned world that when endeavor ceases, motion ceases, and also that everything of determination is in endeavor, and that in motion there is nothing real except endeavor. It is clear that this force or endeavor in action or motion is the spiritual in the natural; for to think and will is spiritual, and to act and be moved is natural. It is true that those who do not think beyond nature do not apprehend this, and yet they cannot deny it. Nevertheless that in the will and thence in the thought, which produces, is not alike in form to the action that is produced; for the action merely represents that which the mind wills and thinks. [AC5173]
They who despise and ridicule the Word in the letter, and still more who do this to the things contained therein in the deeper sense, and consequently to the doctrinal things that are from the Word, and who at the same time are in no love toward the neighbor, but are in the love of self, bear relation to the vitiated things of the blood, which find their way into all the veins and arteries, and taint the whole mass. Lest by their presence they should bring anything of the kind upon man, they are kept separate from others in their own hell, and communicate only with those who are of this nature; for these throw themselves into the breath and sphere of that hell. [AC5719]
Those who do not examine themselves, are comparatively like invalids whose blood is vitiated by the closing of the capillary vessels, which causes atrophy, numbness of the limbs, and painful chronic diseases arising from a thickening, tenacity, acridness, and acidity of the humors, and consequently of the blood. But on the other hand, those who examine themselves even as to the intentions of the will, are like those who have been cured of these diseases, and restored to the life they enjoyed in youth. Those who examine themselves properly, are like ships from Ophir laden with gold, silver, and valuables; but before they have examined themselves they are like ships loaded with filth, such as are used to carry off the mud and ordure of the streets. Those who examine themselves interiorly become like mines, all the walls of which are resplendent with ores of precious metals; but before this, they are like marshes with foul exhalations, containing snakes and poisonous serpents with glittering skins and noxious insects with shining wings. Those who do not examine themselves are like the dry bones in the valley; but after they have examined themselves, they are like these same bones when the Lord Jehovah had laid sinews upon them, caused flesh to come upon them, covered them with skin, and put breath in them, and they lived (Ezek. 37:1-14). [TCR534]
Author: EMANUEL SWEDENBORG (1688-1772)