THE NATURAL BASIS
THE THYMUS GLAND
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 toIt will be seen that there are several phrases that indicate a leaning more towards the celestial than the spiritual. Celestial quality is suggested by "interior perception," "the goodness of things," "soft infantile quality," and "perception of good." Less concern with the spiritual (except as derived from the celestial) is shown by "does not become so visual," "not so much so about their truth," and "from this perception truth shines forth in a general manner." After a few points of anatomy and physiology, the implications of an organ with celestial correspondences having such functions as the thymus will be considered.
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
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.
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.
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
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.
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).
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
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
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
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
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
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.
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,
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.
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