CHAPTER X

The thymus has strong celestial associations

251. The relatively large size of the thymus in the very young and its importance to them suggests that its correspondences are specially celestial, for the spirits of infants are with celestial angels (AC 5342:2). The celestial associations of the thymus are confirmed in AC 5172 which is short enough to quote in full:

There are certain upright spirits who think without reflection, and who therefore rapidly and as it were without premeditation utter whatever occurs to their thought. They have an interior perception, which does not become so visual by means of reflection and thought as is the case with others; for in the course of their lives they have been as it were self-instructed about the goodness of things, but not so much about their truth. I have been told that such persons belong to the province of the thymus gland; for the thymus is a gland especially serviceable to
infants, and during infancy is soft. In such spirits likewise there remains a soft infantile quality, into which flows the perception of good, and from this perception truth shines forth in a general manner. These spirits can be in great turmoils without being disturbed, as is also the case with the gland in question.

The thymus is the principal organ of the lymphoid system

252. This will become clear when the activities of the thymus have been described, but first some anatomical background may be useful. A more complete account is to be found in Gray's Anatomy (Williams, 1980). Advances are now so rapid that the most recent edition should be consulted. In infants, the thymus is a sizeable gland situated in the upper part of the chest and extending into the base of the neck. It diminishes in size after puberty reaching, in adults, an average weight of only 12-15g; nevertheless it is still important for adults. See Figure 12. The thymus is in some ways similar to the spleen or a lymph node in being a spongy structure in the interstices of which numerous lymphocytes are stored. In one respect, however, it is in direct contrast with the spleen; whereas particles as large as erythrocytes are allowed to escape from blood vessels into the spleen (No. 227), in the thymus even some very small molecules are denied access. This applies, for example, to the molecules
of antigens. The experimental finding that antigens cannot get into the thymus is linked with microscopic observations which show that the whole gland is surrounded by a membrane which also covers all the blood vessels, including capillaries inside the gland. There is thus a barrier between the blood and the gland itself. However the barrier is not absolute. Waste products, products of metabolism, and some lymphocytes escape, and nutrients also get in, as do stem cells (see below, No. 255). See Figure 13.

  The Thymus 
 

     A:  Appearance of thymus in newborn. The thymus gland is located in the ventral part of the mediastinum behind the sternum. It reaches its largest relative size at two years of age, and its largest absolute size in adolescence. 
      B: Section of the thymus showing internal structure. Although the section seems to show some lobules completely enclosed, they are not so in fact (in a different plane), but are continuous in the central parts of the lobe. 

 Sources: A: Modified from Clemente, Gray's Anatomy, fig. 10-46. B: Based on Wilson, Human Anatomy, fig. 10-2; Qemente, Gray's Anatomy, fig. 10-48.

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Tissues of the Thymus Gland
 

     A representation at the cellular level of the special tissues and arrangements in the thymus gland. Bone marrow stem cells in the blood stream enter the cortex of the thymus gland, there proliferate greatly, then move to the medulla during maturation, where some of them become immunocompetent and then migrate to secondary lymphoid organs including lymph nodes and spleen. 

      Redrawn by Thomas Rose from Norman Berridge's sketch and from William and Warwick, Gray's Anatomy, ed. 37,1980, p. 835; redrawn, partly by computer, by Alan Laidlaw and Charles Cole from Rose's and Berridge's drawings plus the following: Roitt, Brostoff and Male, Immunology, 1985, Fig 14.3; Rubenstein and Federman, Scientific American Medicine, 1990, Fig. 2, p. 6:1:4.

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253. In the new-born, the thymus is essential for the development of peripheral lymphoid tissues such as lymphocytes, lymph nodes, tonsils, etc. This statement, however, only indicates what happens if a young animal is deprived of its thymus gland. As the lymphoid tissues do not develop, the deprived animal dies fairly soon, because it cannot develop immunity to any infection. In an older animal, the loss of the thymus takes longer to make itself felt, as the lymphatic system is already fully developed and the animal is already immune to the commoner infections of its surroundings. It is, however, unable to respond effectively to new antigens.

254. The thymus is necessary for growth of peripheral lymphoid tissues. In addition to this, it is thought that its central part, or medulla, secretes a hormone-like substance, lymphopoietin, which stimulates production of lymphocytes in those tissues as well as in the outer part or cortex of the thymus itself. Newly produced lymphocytes do not react against antigens. They are said to be incompetent. Lymphopoietin, or perhaps another substance secreted by the thymus, acts as a competence-inducing factor, effecting a transformation of the new lymphocytes to a mature state in which they are competent to produce new antibodies to new antigens. Those lymphocytes that are stored in the thymus do not react against antigens while they are there for, as we have seen, antigens are kept out of the thymus; but the lymphocytes are competent. In due course they leave the thymus and join the general pool of circulating lymphocytes, of which, however, they form only a small proportion.

255. The origin of the lymphocytes of the thymus has been traced to the stem cells mentioned above (No. 252). These come from the bone marrow and when they reach the thymus (presumably via the blood stream) they settle there and multiply. Part of their progeny becomes modified into lymphocytes and the rest continue the function of the parent cells, producing partly lymphocytes in the next generation. In this way a very large number of lymphocytes is produced, but most of them (over nine tenths) die within 3-5 days and are consumed by phagocytes still within the thymus. The phagocytes migrate into certain microscopic structures known as corpuscles of Hassall in the medulla where they in turn disintegrate. Thus there are many short-lived lymphocytes in the thymus and it is thought that some of them are auto-allergic, i.e., that they would produce antibodies against the tissues of their own parent organism. Possibly this property causes the lymphocytes to be recognized as
"foreign" by the phagocytes which engulf them. Failure on the part of phagocytes to remove efficiently all auto-allergic cells is considered to be the cause of auto-immune diseases. The lymphocytes referred to as "stored" in No. 254 are longer lived. They are the five percent or so that are not destroyed and that eventually leave the thymus in small numbers. They are competent but uncommitted.

The tranquility of the thymus is readily explained in terms of anatomy and physiology

256. How can a gland be in great turmoils without being disturbed, as is said in AC 5172? The barrier between the thymus and the blood was mentioned in No. 252 just above. It is clearly the structure responsible for "as is also the case with the gland in question." When the body all around the thymus is in great turmoils, owing perhaps to some disease, the gland itself is protected by its barrier from the toxins. It can remain  undisturbed so as to be able to direct, as it were, the operations of defence, despite the many germs pouring into the body. What seemed to be a puzzling phrase is easily understood when the facts are known.

Correspondences of the lymphatics show that the defence of good is derived from the interiors of knowledge

257. At first it seems very strange that the stem cells which are essential for the functioning of the thymus should come from the bone marrow, because we find that in the Writings bones are often considered as relatively inert, or as having but little life. How then should they produce such important lively reproductive cells? Some comments on the life in bones were made earlier (Berridge, 1980 A, p. 22) where their correspondences with scientifics (KEM) were discussed. The gentle love which forms KEM and the knowledge and use which harden them like bones were mentioned, but to that must be added the specific teaching quoted above (No. 232) to the effect that KEM should contain goods (which are of love, thus soft and living).[14] Regarded in this light, the correspondences all go nicely together, but still there must be many more repercussions of this strange process. We have cells from one environment making, as it were, a journey to a strange new environment in which
they become highly productive. One is reminded of the sojourn of Jacob with Laban. In psychological terms we may say that we have thoughts of good leaving an environment of truth to enter another of innocence and love. There they form a whole army of quite inoffensive but extremely effective defensive thoughts, without which the kingdom of the soul cannot survive the onslaughts of hell. Such a theme might well suffice for a whole volume of sermons, could we but see the details clearly.

The activity of the thymus shows how the celestial operates upon the natural

258. An interesting aspect of the central control exerted by the thymus on the peripheral lymphoid tissues is that, although the thymus is essential for the defence of the body against all kinds of antigens, it cannot itself produce any effective defensive action. The small number of lymphocytes that leave it would presumably be inadequate. The thymus thus represents in a striking manner the activity of the celestial internal of man which cannot operate into the natural without a means of communication. Concerning this we read that "by the interior man the internal man communicates with the external; without this medium, no communication at all is possible. The celestial is distinct from the natural…and unless there is a medium by which there is communication, the celestial cannot operate at all into the natural…" (AC 1702:2). The thymus cannot operate into the body without the medium of the peripheral lymphoid tissues. We read further in the same passage that "it is the interior
man which is called the rational man; and this man, because it is intermediate, communicates with the internal man, where there is good itself and truth itself; and it also communicates with the exterior man, where there are evil and falsity." The exterior man, where there are evil and falsity, may be thought of as corresponding to the body, where there is disease. The internal which is celestial is, like the thymus, too infantile and gentle to fight, but it can mount an effective defence through the intermediate or rational corresponding to the lymphatics.

259. There is a correspondence between remains and lymphocytes

Having suggested that the lymphatics correspond to the interior man, we notice next that remains are stored in the interior man.
    There are a number of terms for the various kinds of white cells that populate the lymph and the blood. Strictly, lymphocytes should include all that are to be found in the lymph, but it is often convenient to distinguish between phagocytes which means cells that eat (like amoebae) and the round cells that produce antibodies. These have often been called lymphocytes in contrast to phagocytes, but here by lymphocytes both kinds are meant. There are so many kinds of cells that the more one begins to be precise the more different kinds there appear to be, as distinguished, for example, by function and staining properties. Lymphocytes are stored in the lymphatics i.e., in the nodes, spleen, etc. Hence it is worth while to compare lymphocytes with remains. Remains are goods and truths stored up by the Lord in the interior man (AC 5342:3, 5897:11). Everything of spiritual life is from remains (AC 5898). It is therefore difficult to see how the interior man, where they are stored, could correspond to such a limited system as the lymphatics, or how the things through which all spiritual life comes could correspond to such specialized single cells as lymphocytes. On the other hand, in the very next number (AC 5899), deliverance from damnation is said to be effected by means of remains, which may therefore be termed a means of defence. In a sense the natural and the spiritual are parallel. In the disease-ridden environment we are used to, there would be no life for us without a good defence by the lymphatics. Spiritually, we are surrounded by evils and falsities against which the Lord continually fights by means of the remains He has stored within us. Otherwise there would be no life for us. Is this what is meant by "everything of spiritual life is from remains"? It seems more probable that there are many kinds of remains, of which some are more militant than others. (See no. 261.) Similarly, though the thymus may correspond to the celestial, it might be difficult to find all the celestial qualities clearly represented therein. Nevertheless, correspondence is the means by which life from the spiritual world can flow into and cause the natural, however limited the latter may appear to be. As is widely known, each individual's unique DNA is replicated in every ordinary cell, and this provides another representation of the truth that in spiritual things the part is an image of the whole.
Therefore the correspondence of the lymphatic organs, both central and peripheral, can provide an image of the whole man. The limitations that have been mentioned need not hinder a fuller exploration of the possible correspondences.

There is also a correspondence between remains and antibodies

260. When immunity was considered earlier (No. 207) it was described as a blanketing reaction by an antibody whose molecules would fit only those of the intruding antigen. This means that each antibody is unique, but many antibodies are formed from the same series of units (20 or so amino acids and a few sugars). By linking the units into one specific sequence a lymphocyte is able to make one specific antibody. Another lymphocyte, "programmed" differently, will make a different antibody. An uncommitted lymphocyte is induced to make an antibody by the resence of an antigen. This seems to be an automatic process. Nevertheless it is a kind of information which the lymphocyte receives and upon which it acts: namely, information about the molecular "shape" of the antigen. Correct information is truth, so that we may think of the whole process as the qualifying of good by truth (AC 5342:3), the amino acids and sugars being the good, and the order according to which
they are put together being the truth. Thus once again we see that truth is the form of good, and as "Remains" in the proper sense (AC 5342:3) are "truths adjoined to good," we may think of the antibodies themselves as corresponding to remains, or perhaps to a particular kind of remains.

261. It has now been indicated that both lymphocytes and antibodies correspond to remains. The two former are certainly related but they are not the same. It has also been suggested that there are many kinds of remains. Even in AC 5342 we find signs of three. First, there are the goods of innocence and charity which are later withdrawn and stored up. These are called remains in AC 661. Then there are truths "conjoined with good"; and finally, "it is these truths adjoined to good that in the proper sense are called 'remains'" (assuming that "conjoined" is not the same as "adjoined"). The statement about remains in AC 661 might be summarized by saying that remains are all things of innocence, of charity, of mercy, and of truth. "All things" must embrace quite a variety. The wording of AC 5342 leads one to think that the goods of innocence and charity might not be "remains" in the proper sense because they are not withdrawn from store for use as are the "remains" proper. They are like
the stem cells and other tissues of the thymus that remain in that gland behind the protection of its special membrane, whence they exert their so important influence.

262. Having established that there is a variety of remains, we explore next the close relationship between lymphocytes and antibodies. It is not only that one is the producer and the other the product, but also that the lymphocyte contains within its cell a molecular shape (DNA). This controls the sequence according to which the amino acids are linked together to make the antibody. Thus in regard to essentials there is a point of great similarity.

263. We may take the correspondences a step further and compare a lymphocyte to an angel. Both are living units. The lymphocyte fights against a disease by putting together molecules provided by the body, doing this according to "information" or "skill" which only the lymphocyte has. An angel combats evil in a man by taking his good (i.e., the Lord's good in the man) and qualifying it with his truth so as to make it effective, doing this from the Lord with a skill which only angels possess. The conjunction of love and truth and protection by angels as described in AC 5893 seems to be in harmony with the activities of lymphocytes. Hence possibly angels correspond to remains, which correspond to lymphocytes; but also, of course, all societies in heaven correspond to societies of spirits, which correspond to the body.

264. A fascinating account of how a lymphocyte is changed (i.e., committed) by meeting an antigen and "remembering the experience" is given by Martin M. Echols as part of an article about analogies between mental processes and the biochemical behavior of cells (Echols, 1980 A, p. 18). The events he describes are remarkable enough to make it easy to accept a correspondence with remains and angelic influences.

The development of man's soul can be seen as in a mirror in the growth and use of the lymphatic system

265. Concerning the beginning of man's life we read that "from earliest infancy to the beginning of childhood, man is being introduced by the Lord into heaven, and indeed among celestial angels, by whom he is kept in a state of innocence" (AC 5342:2). This is the state in which the thymus is a relatively large organ, and the peripheral lymphoid tissues are not yet adequately developed. At least two causes operate to preserve the very young who cannot easily become immune. The first is that they are usually in a protected environment with the mother; the second (and more important) is that they do have some immunity derived from breast milk. Both of these seem to be correspondences of being among celestial angels. It is worth noting also that, as the influence of the thymus is necessary for the growth of the peripheral lymphoid tissues, so also the remains from the early celestial period are necessary for future regeneration. This has its correspondence at an intermediate level also,
for, as is well known, depriving an infant of maternal love in its earliest life can have serious consequences.

266. "When the age of childhood begins, the child gradually puts off the state of innocence…and meanwhile he is among spiritual angels" (AC 5342:2). This state includes the development, or at least the beginning, of the rational; and the corresponding state of the body would be that in which the peripheral lymphoid tissues are growing. Both spiritually and naturally, preparations are being made for resistance to harmful forces.

  267. When the youth begins to think from himself and to be led by evils, the goods of charity and innocence "are withdrawn by the Lord towards the interiors and there stored up" (AC 5342:2). Here it is difficult to see an exactly parallel correspondence, but there may well be some connection with the storage of lymphocytes which takes place in the peripheral lymphoid tissues (nodes, spleen, etc.). Also, the "inherited evils by which he suffers himself to be led" could correspond to inherited weaknesses which commonly allow infectious diseases to reach serious proportions.

268. The youth we are following through AC 5342 has the goods of innocence and charity, but these goods "have not yet been qualified, for truths give quality to good, and good gives essence to truths; wherefore from this age he assimilates truths by instruction, and especially by means of his own thoughts and confirmations therefrom." The goods which have not been qualified by truths are like new lymphocytes which are not committed to making any antibodies, and probably not even competent to react against any antigens. So it is that we find next a correspondence of the competence-inducing factor from the thymus, for we read, "in so far, therefore, as he is then in the affection of good." An affection of good is derived from the celestial, just as the competence-inducing factor is derived from the thymus, which we have suggested corresponds to the celestial. Later, our youth has his truths adjoined to good, which remains are available for use in regeneration, that is, for defence in temptations, as competent lymphocytes defend during disease, and in due course confer immunity.

Immunity provides an example of "cometh of evil"

269. Foreign substances in the body, especially antigens produced by invading micro-organisms, are regarded as correspondences of evil. The production of antibodies suggests that good is qualified by truths only in response to evil--even that the form into which the good is qualified is related (as an opposite) to the evil that is to be overcome, and that the truth is available only for this purpose. Obviously, not all truth is for the sake of fighting against evil. There is much that is sheer delight and life to those who are in good. There is also much that is only for combat; hence the Lord said "whatsoever is more than these cometh of evil" (Matt. v. 37). Perhaps not much reliance should be placed on the choice of a preposition, especially in a translation, but it is interesting that we find "cometh of evil" and not "from evil." This suggests that the faith of truth (see DLW 427, 428) is made necessary because of evil, as antibodies are necessary because of disease. They are of the disease but
not from the infecting organisms.