# Letters on the Human Body/Letter 7

LETTER VII.
    My Dear Sir,
My Dear Sir In some former letters on the wonderful mechanism and operations of the human body, I have confined my remarks to those parts of it which may be regarded as constituting its more external organization, such as its external form and external senses. Will you allow me now to call your attention to a more interior subject, by presenting to your view a slight sketch of the internal provisions made by the ALMIGHTY for the promotion of bodily health and of other uses, as they are discoverable in the astonishing acts of digestion, absorption, secretion, excretion, &c., of the several parts of food admitted by eating and drinking?
If you have ever consulted the works of our most ​celebrated anatomists on those interesting subjects, you cannot fail to have discovered, that when food is let down through the œsophagus into the stomach, it is there for a time kept in a state of convolution, until it is opened and separated, that is, digested by various menstrua; and in this state is partly received by what are called the lymphatic vessels, partly by the lacteal vessels, and partly let down into the intestines. This reception of the purer contents of the stomach by the lymphatic and lacteal vessels is what is called absorption, being effected by what are termed the absorbent vessels, whilst the separation of the more impure contents, by being let down into the intestines and by other processes, is what is called secretion and excretion. You must further have discovered, that the purer parts of the digested food, which are received by the lymphatic vessels, are called lymph, from their resembling in appearance a watery fluid; whilst the purer parts received by the lacteal vessels are called chyle, which in its aspect resembles milk, and is by some writers called white blood, to distinguish it from the red, into which it is finally converted. Lastly, you must have discovered, that the stomach is the organ, in which the separation commences of what is capable of remaining in the body for its health and nourishment, from what is incapable; that is to say, ​from what, if remaining there, would prove injurious to the life and health of the body; and that this separation is afterwards continued in the intestines, even to the colon and rectum, where the noxious matter is finally ejected from the body.
Taking it for granted then, that you are in possession of all this information, and that you have besides made yourself acquainted with the singular form of the stomach, where all these extraordinary operations commence; and likewise with the multiplicity and mechanism of the absorbent and secreting vessels, where the same operations are continued; will you allow me to ask you, what are the real sentiments of your mind respecting all these wonders? Can you believe it possible that the body, which is of itself a mass of mere matter, is capable either of designing or of accomplishing such stupendous purposes? Or is it to be supposed that what is called nature, which in itself is dead, being created for the reception of life, but not possessing any life properly its own, hath the ability to produce such living activities? I am persuaded that your intelligent mind revolts at such ideas, as being utterly irreconcilable with all the dictates of sound reason, and also in direct opposition to all the wisdom of DIVINE REVELATION. You will therefore, I doubt not, agree with me, tat no satisfactory solution can ​possibly be given of the above phenomena of digestion, absorption, and secretion, which are discoverable in every living body, but by referring them to the agency of some active principle superior to the body, and superior also to nature,—thus primarily proceeding from, and in close connection with, GOD—the alone DIVINE FOUNTAIN of all life and of all activity.
But at what an interesting and edifying conclusion are we now arrived! On what high and sacred ground too do we stand, whilst contemplating the supernatural momentary operations which are transacting and presented continually to our astonished view in our own bodies! What pious mind therefore is not led, on this occasion, to adopt the language of the Patriarch of old, when awaking out of sleep, “Surely the LORD is in this place; and I knew it not. How dreadful is this place! this is none other but the house of GOD, and this is the gate of heaven?” [Gen. xxviii. 16, 17.]. For is it an indisputable fact, that a chemical process is every instant carrying on in the deep centre of our corporeal frame, over which process we have no control, and which can only be accounted for by referring it to the agency of some power above ourselves? Are transmutations of solids into fluids, and their translations from one part of the body to another, continually going forward in the alembic of ​that organized matter which forms the stomach, and in the absorbent and secreting vessels with which it is encompassed? Is a separation thus effected between what is salutary to the constitution and what is noxious, so that what is salutary is by degrees incorporated into the life, and what is noxious is discarded and ejected? Is the number of vessels also requisite for these purposes out of the reach of all numerical computation, some of them being so minute as to be indiscernable to the naked eye? Lastly, are we compelled to confess, that a latent superior power, like a skilful but invisible alchemist, is ever present, ever operative, ever watching over, directing and forwarding the above processes? Is this, I say, a correct statement of the practical and experimental philosophy of the human body? Then what intelligent mind is not constrained to exclaim, “Surely the LORD is in this place; and I knew it not:” and then too, observing that the human body is the laboratory of so many wonders, will not the same mind be disposed to add, “This is none other hut the house of GOD, and this is the gate of heaven?”
Astonishing, however, as are these digestions, absorptions, and secretions, when considered as momentarily effected in the kingdom of matter, it ought to be recollected that they become infinitely more so when viewed in their connection with similar processes in ​the kingdom of mind, and especially when seen as figurative of these latter processes.
You are surprised, I see, at hearing of any such connection and figure: allow me then to endeavour to explain myself on the interesting subject.
In my former letters on the bodily senses, and also on the bodily acts of eating and drinking, I have attempted to convince you, that there is nothing transacted in the body of man, in a bodily way, but what is transacted also in his spirit in a spiritual way; thus that as the body sees, hears, smells, feels, eats, and drinks, so likewise doth the mind, or spirit—with this only difference, that all those acts, in one instance are of the body in conjunction with its mind, or spirit, and in the other instance are solely and exclusively of the mind. The mind therefore hath its food, as well as the body, which mental food is every thing that hath respect to science, intelligence, and wisdom. Consequently, the mind hath its faculty of digesting its food, since intelligence is nothing else but well digested science; and wisdom is nothing else but well digested intelligence; and accordingly the term digestion is applied to the mind by the best English writers, as your own extensive acquaintance with those writers may serve to convince you.
But if digestion be applicable to the mind, so likewise ​must absorption and secretion be, since these latter acts are in necessary connection with the former; absorption implying a reception into the body of such parts of the digested food as may tend to its nourishment, and secretion implying the rejection of such parts as might otherwise prove injurious.
Behold here, then, the established analogy between the nourishment of the body by means of material food, and the nourishment of the mind, or spirit, by means of spiritual food! Material food is first received by the bodily mouth, and after the processes of mastication and deglutition is let down into the stomach, for the purpose of a more interior introduction into the body. In like manner, spiritual food is first received into the external memory (the mind’s mouth), under the form of science, and being there well masticated by thought and meditation, and afterwards swallowed, or forced more interiorly into the mind, is thus submitted to rational consideration, for the purpose of digestion. Material food again, when well digested in the stomach, undergoes a separation of its parts, so that what is salubrious is absorbed, and thus admitted more intimately into the body, whilst what is noxious is secreted, and thus cast out. Spiritual food, or science, in like manner, by digestion, is distinguished as to its component principles, and the consequence is, that the ​purest of those principles are elevated more inwardly into the mind, where they acquire a new form, and receive a new name,—being no longer called science, but dignified by the higher title of intelligence, because seen in intellectual light, or the light of the understanding. Lastly, material food, when by natural absorption it has been admitted into the lymphatic and lacteal vessels, under the form of lymph and of chyle, or white blood, is finally introduced to conjunction with the red blood, and is thus more intimately and fully incorporated with the life of the body. Spiritual food too, when by spiritual absorption it has been elevated into the understanding, so as to be viewed and cherished there with the affection of truth, is by degrees exalted to a higher place in the interiors of the mind, being viewed and cherished with the affection of good; and thus raised out of the understanding into the will, and consequently admitted to its supreme abode in the love and life, from which abode it rules and governs all inferior principles and operations.
The above analogy might be illustrated, if necessary, by a thousand instances; but perhaps one will be sufficient to prove that the mind, as well as the body, hath its powers of digestion, of absorption, and of secretion, and that, if those powers are not exercised, it is impossible that any mental food can be fully ​received and admitted by it. Let us take then our proof from this Divine precept, contained in the HOLY WORD of the MOST HIGH, “Thou shalt love the LORD thy GOD with all thy heart, and with all thy soul, and with all thy mind,” [Matt. xxii. 37.; Mark xii. 30.; Luke x. 27.]
This Divine precept, it is plain, may be viewed under three distinct forms, and impressed on man in three distinct degrees, according to its reception, first in the memory, secondly in the understanding, and thirdly in the will; in other words, first as science, secondly as intelligence, and thirdly as wisdom. It is equally plain, that if the precept be received only as science in the memory, it gains no admission into the mind, or spirit, of man, since the memory is merely an outer court leading to the mind, but makes no part of the mind itself. Nevertheless, as an outer court, it has its important uses, since under that character it serves as a storehouse, in which the documents of what is good and true may be deposited, for the purpose of their being afterwards elevated into the higher or interior principles of the understanding and will.
Let us suppose now, that the above Divine precept, “Thou shalt love the LORD thy GOD with all thy heart, and with all thy soul, and with all thy mind,” has been admitted and deposited in the memory. What eye ​cannot see, that if it remains there, without any elevation thence into the higher chambers of understanding and will, it gains no admission into the mind itself; and, consequently, lies buried as an useless precept, neither enlightening the mind with intelligence, nor enlivening it with wisdom? What eye therefore cannot discern further, that some additional process is necessary to give to the precept all that power of imparting to man the blessings of eternal life and bliss, which it was intended to exercise? But what shall we say is this additional process, or what can it be, but serious thought and serious purpose? And what is serious thought and serious purpose, but mental digestion, mental absorption, and mental secretion; by virtue of which acts, a truth deposited in the memory is raised out of it into the understanding, and from the understanding into the will; and thus from science becomes intelligence, and from intelligence becomes wisdom; and from all three united rejects every evil affection, thought, and act, and thus renders man the blessed child of his HEAVENLY FATHER, Who is never satisfied until His children both know His will, and by knowing understand it, and by understanding love it, and from loving practise it?
Yet what is thus true of the above single precept, is equally true of every other precept contained in the ​Sacred Scriptures, since there is every reason to believe, that not one of them can gain admission into the mind and life of man, until by serious thought and serious purpose it has been well digested, through the combined effects of absorption and secretion.
Do you ask what this absorption and secretion mean, when applied to the other and more general precepts of GOD’S MOST HOLY WORD? I wish to answer, that by absorption and secretion, as thus applied, is to be understood the separation between the genuine sense of every precept and its apparent sense; in other words, between the spiritual sense and the literal sense, that so the Divine spirit and life of every precept may be elevated into the understanding and will, and at the same time, the appearances presented in the letter, or history, may be separated. As for example, JESUS CHRIST declares, “Whosoever he be of you that forsaketh not all that he hath, he cannot be my disciple;” [Luke xiv. 33.]; in which words there is contained a double sense, viz. a genuine and an apparent one; the genuine sense teaching, that the words do not apply to man’s natural property, such as houses, lands, &c. but to his spiritual property,—that is to say, to his spiritual powers, talents, &c.; whilst the apparent sense teaches, that in the same words is included and expressed the necessity of man’s divesting himself of all natural property, as a ​qualification to become a disciple of the GREAT SAVIOUR. The genuine sense therefore teaches further, that man can never become a disciple of JESUS CHRIST,—in other words, can never be taught of Him, until he forsakes all his spiritual property, by acknowledging it, in humility and gratitude, to be really and truly the property of the MOST HIGH. To distinguish then between these two senses, so as to elevate the spiritual sense into the understanding and will, and to discard the literal sense, is the proper office of spiritual absorption and secretion, so far as it regards the reception and incorporation of the WORD OF GOD into the mind and life of man. Secretion too, in a more extended sense of the term, may apply to all those natural affections and thoughts which, being grounded in self-love and the love of the world, have a tendency, if unremoved, to obstruct the elevation of the principles of the Divine love and wisdom to their due ascendancy and rule in the human will and understanding.
You see then, my good Friend, of what vast importance it is, that the operation of mental digestion, especially when applied to the precepts of the HOLY WORD OF THE MOST HIGH, be well attended to; since otherwise it is as absolutely impossible, that those ​precepts should gain that interior admission into the mind and life of man which they were designed to gain, as that bodily food, without being well digested, should gain its proper and profitable admission into the body. Man thus, with the Bible in his hand, and even in his memory, may be as great a stranger to its living and saving contents as if he had never heard of the HOLY BOOK; so that even the Divine precept, above alluded to, “Thou shalt love the LORD thy GOD with all thy heart, and with all thy soul, and with all thy mind,” would be totally void of spiritual nourishment, and more like a dead husk than the living kernel of Divine wisdom and salvation. For supposing that a man reads this precept, and yet, after reading it, is never led by serious consideration and purpose to ruminate on what is properly meant by loving, as applied to the GREAT and HOLY GOD; on what also is involved in the sacred title of the object to be loved, THE LORD THY GOD; and lastly, on the distinct terms the heart, the soul, and the mind, as marking the distinct principles by and from which He is to be loved; what eye cannot see, in such case, that the precept would remain useless, and so far from being the meat which endureth to eternal life, would rather be converted into the meat which perisheth, or into that ​chaff, of which it is written, that the wind driveth it away? [Psalm i. 4.].
I cannot conclude my letter on the above important subject of spiritual digestion, absorption, and secretion, without calling to your recollection the words of the GREAT SAVIOUR respecting the light, which He, as a HEAVENLY SUN, came to dispense to a dark world, when He says, “While ye have light, believe in the light, that ye may be the children of light,” [John xii. 36.]. For how forcibly do these words apply to the light of that DIVINE TRUTH, with which the WORD OF GOD throughout is replenished! How exactly, too, do the three distinct characters of having the light, of believing in the light, and of becoming the children of the light, correspond with the distinct acts of receiving the DIVINE TRUTH into the memory, into the understanding, and into the life, thus with the distinct acts of spiritual digestion above described! How plain therefore is it to see, that it is possible to have THE TRUTH without believing in it, and to have and believe in it without becoming its children; and that, consequently, THE TRUTH can never be fully and effectually received by mankind, until it be fully and effectually digested, by being first deposited in the memory, which is to have it; and ​by being next elevated into the understanding, which is to believe in it; and lastly by allowing it the supreme rule and ascendancy in the will and life, which is to become its children!
Whilst then, in the spirit of profound humiliation and adoration, we magnify that inconceivable goodness and wisdom, which devised and constructed the bodily organs of bodily digestion, absorption, and secretion, for the purpose of promoting bodily health and strength, may we ever be wise to recollect, that these organs and their operations are but figures of those more astonishing powers of the mind, by which it is enabled to exercise mental digestion, absorption, and secretion, in regard to that BREAD OF LIFE which is given in the WORD OF GOD for its daily sustenance! May the reception of this BREAD be accordingly our grand concern! And may we never forget, that if there be one folly more extravagant or more perilous than another, it is the folly of supposing, that a medicine can be of any use to a sick man whilst he keeps it in his pocket, instead of taking it into his stomach, and allowing it there to exercise its healing, digesting, and secreting properties; or that food can be of any benefit to a hungry man, so long as, like the Syrian lord, ​[2 Kings vii. 2.], he only sees it with his eyes, but doth not eat thereof.
In devout prayer, that you, my good Friend, may experience all the benefits, both spiritual and natural, both eternal and temporal, to be derived from a good digestion, with its attendant operations of absorption and secretion, I remain
Yours truly, &c.