Supplementary Appendix: Of the Brunonian Doctrine

Thomas Beddoes
“Of the Brunonian Doctrine” [*]

A complete investigation of Dr. Brown’s theory of living nature, with its application to the knowledge and treatment of diseases, would, at least, equal the original work in size; besides, if I had any inclination to write such a commentary, I should not consider this as the proper place for introducing it. I have, however, a few words to fay on the outlines and formation of the system. I shall subjoin some reflections to put medical students and readers, not professional, in the way of profiting by the true principles he promulgated without being misled by his doubtful or erroneous positions.

Of Dr. Brown’s Fundamental Propositions.

The varied structure of organized beings it is the business of anatomy to explain. Consciousness, assisted by common observation, will distinguish animated from inanimate bodies with precision more than sufficient for all the ends of medicine. The cause of gravitation has been left unexplored by all prudent philosophers; and Brown, avoiding all useless disquisition concerning the cause of vitality, confines himself to the phaenomena, which this great moving principle in nature may be observed to produce. His most general propositions are easy of compreheniion.

I. To every animated being is allotted a certain portion only of the quality or principle, on which the phaenomena of life depend. This principle is denominated excitability.

II. The excitability varies in different animals, and in the same animal at different times. As it is more intense, the animal is more vivacious or more susceptible of the action of exciting powers.

III. Exciting powers may be referred to two classes, 1. External, as heat, food, wine, poisons, contagions, the blood, secreted fluids, and air. 2. Internal, as the functions of the body itself, muscular exertion, thinking, emotion and passion.

IV. Life is a forced state; if the exciting powers are withdrawn, death ensues as certainly as when the excitability is gone.

V. The excitement may be too great, too small, or in just measure.

VI. By too great excitement weakness is induced, because the excitability become[s] defective; this is indirecl debility: when the exciting powers or stimulants are withheld, weakness is induced; and this is direct debility. Here the excitability is in excess.

VII. Every power that acts on the living frame, is stimulant, or produces excitement by expending excitability. Thus, although. a person, accustomed to animal food, may grow weak if he lives upon vegetables, still the vegetable diet can only be considered as producing an effect, the same in kind with animals, though inferior in degree. Whatever powers therefore, we imagine, and however they vary from such as are habitually applied to produce due excitement, they can only weaken the system by urging it into too much motion, or suffering it to sink into languor.

VIII. Excitability is seated in the medullary portion of the nerves, and in the muscles. As soon as it is any where affected, it is immediately affected every where; nor is the excitement ever increased in a part, while it is generally diminished in the system; in other words, different parts can never be in opposite states of excitement.

I have already spoken of an illustration, drawn up by Mr. Christie from a familiar operation, to facilitate the conception of Brown’s fundamental positions. I introduce it here as more likely to answer its purpose than if separately placed at the end of my preliminary observations.

Suppose a fire to be made in a grate, filled with a kind of fuel not very combustible, and which could only be kept burning, by means of a machine containing several tubes, placed before it, and constantly pouring streams of air into it. Suppose also a pipe to be fixed in the back of the chimney, through which a constant supply of fresh fuel was gradually let down into the grate, to repair the waste occasioned by the flame, kept up by the air machine.

The grate will represent the human frame; the fuel in it, the matter of life, the excitability of Dr. Brown and the sensorial power of Dr. Darwin; the tube behind supplying fresh fuel, will denote the power of all living systems constantly to regenerate or reproduce excitability; while the air machine, of several tubes, denotes the various stimuli applied to the excitability of the body; and the flame drawn forth in consequence of that application represents life, the product of the exciting powers acting upon the excitability.

As Dr. Brown has defined life to be a forced state, it is fitly represented by a flame, forcibly drawn forth, from fuel little disposed to combustion, by the constant application of streams of air poured into it from the different tubes of a machine.

If some of these tubes are supposed to convey pure or dephlogisticated air, they will denote the highest class of exciting powers, opium, musk, camphor, spirits, wine, tobacco, &c. the diffusible stimuli of Dr. Brown, which bring forth for a time a greater quantity of life than usual, as the blowing in of pure air into a fire will temporarily draw forth an uncommon quantity of flame.

If others of the tubes be supposed to convey common or atmospheric air, they will represent the ordinary exciting powers, or stimuli, applied to the human frame, such as heat, light, air, food, drink, &c. while such as convey impure and inflammable air may be used to denote what have formerly been termed sedative powers, such as poisons, contagious miasmata, foul air, &c.

The reader will now probably be at no loss to understand the seeming paradox of the Brunonian system; that food, drink, and all the powers applied to the body, though they support life, yet consume it; for he will see, that the application of these powers, though it brings forth life, yet at the same time it wastes the excitability or matter of life, just as the air blown into the fire brings forth more flame, but wastes the fuel or matter of fire. This is conformable to the common saying, “the more a spark is blown, the brighter it burns, and the sooner it is spent.” A Roman poet has given us, without intending it, an excellent illustration of the Brunonian system, when he says,

Balnea, Vina, Venus, consumunt corpora nostra, 
Sed Vitam faciunt Balnea Vina Venus.

Wine, warmth, and love our vigour drain;
Yet wine, warmth, love, our life sustain.

Or to translate it more literally,

Baths, women, wine, exhaust our frame,
But life itself is drawn from them.

Equally easy will it be to illustrate the two kinds of debility, termed direct and indirect, which, according to Brown, are the cause of all diseases. If the quantity of stimulus, or exciting power, is proportioned to the quantity of excitability, that is, if no more excitement is drawn forth than is equal to the quantity of excitability produced, the human frame will be in a state of health, just as the fire will be in a vigorous state, when no more air is blown in, than is sufficient to consume the fresh supply of fuel constantly poured down by the tube behind. If a sufficient quantity of stimulus is not applied, or air not blown in, the excitability in the man, and the fuel in the fire will accumulate, producing direct debility, for the man will become weak, and the fire low.

Carried to a certain degree they will occasion death to the first, and extinction to the last. If again, an over proportion of stimulus be applied, or too much air blown in, the excitability will soon be wasted, and the matter of fuel almost spent. Hence will arise indirect debility, producing the same weakness in the man, and lowness in the fire as before, and equally terminating, when carried to a certain degree, in death and extinction.

As all the diseases of the body, according to Dr. Brown, are occasioned by direct or indirect debility, in consequence of too much or too little stimuli, so all the defects of the fire must arise from direct or indirect lowness, in consequence of too much or too little air blown into it.

As Brown taught that one debility was never to be cured by another, but both by the more judicious application of stimuli, so will be found the case in treating the defects of the fire. If the fire has become low, or the man weak by the want of the needful quantity of stimulus, more must be applied, but very gently at first, and increased by degrees, lest a strong stimulus applied to the accumulated excitability should produce death, as in the case of a limb benumbed by cold (that is weakened by the accumulation of its excitability in consequence of the abstraction of the usual stimulus of heat), and suddenly held to the fire, which we know from experience is in danger of mortification, or as in the case of the fire become very low by the accumulation of the matter of fuel, when the feeble flame, assailed by a sudden and strong blast of air, would be overpowered and put out, instead of being nourished and increased.

Again, if the man or the fire have been rendered indirectly weak, by the application of too much stimulus, we are not suddenly to withdraw the whole, or even a great quantity of the exciting powers or air, for then the weakened life and diminished flame might sink entirely, but we arc by little and little to diminish the overplus of stimulus, so as to enable the excitability, or matter of fuel, gradually to recover its proper proportion.

Thus a man who has injured his constitution by the abuse of spirituous liquors, is not suddenly to be reduced to water alone, as is the practice of some physicians, but he is to be treated, as the judicious Dr. Pitcairn of Edinburgh, is said to have treated a Highland chieftain, who applied to him for advice in this situation. The Doctor gave him no medicines, and only exacted a promise of him, that he would every day put in as much wax into the wooden queich out of which he drank his whisky, as would receive the impression of his arms. The wax thus gradually accumulating, diminished daily the quantity of the whisky, till the whole queich was filled with wax, and the chieftain was thus gradually, and without injury to his constitution, cured of the habit of drinking spirits.

These analogies might be pursued farther; but my object is solely to furnish some general ideas, to prepare the reader for entering more easily into the Brunonian theory, which I think he will be enabled to do after perusing what I have said. The great excellence of that theory, as applied not only to the practice of physic, but to the general conduct of the health is, that it impresses on the mind a sense of the impropriety and danger of going from one extreme to another. The human frame is capable of enduring great varieties, if time be given it, to accomodate itself to different states.

All the mischief is done in the transition from one state to another. In state of low excitement we are not rashly to induce a state of high excitement, nor elevated to the latter, are we suddenly to descend to the former, but step by step, and as one who from the top of a high tower descends to the ground. From hasty and violent changes the human frame always suffers, its particles are torn asunder, its organs injured, the vital principles impaired, and disease, often death, is the inevitable consequence.

I have only to add that though in this illustration of the Brunonian System (written several years ago), I have spoken of tube constantly pouring in fresh fuel, because I could not otherwise convey to the reader a familiar idea of the power possessed by all living systems, to renew their excitability when exhausted, yet it may be proper to inform the student, that Dr. Brown supposed every living system to have received at the beginning its determinate portion of excitability, and therefore, and though he spoke of the exhaustion, augmentation, and even renewal of excitability, I do not think it was his intention to induce his pupils to think of it, as a kind of fluid substance, existing in the animal and subject to the law by which such substances are governed. According to him excitability was an unknown somewhat, subject to peculiar laws of its own, and whose different states we were obliged to describe (though inaccurately) by terms borrowed from the qualities of material substances.

T. C.

It was not unusual for Brown’s disciples to disagree, when they were called upon for a strict interpretation of his principal tenets. If they be rigidly examined, they will be found, I think, not quite consistent with his own important doctrine of the accumulation of excitability, during different states of inaction. It appears to me, that according to his first chapters (xviii), living beings ought to have proceeded through languor to death in one unbroken tenour of wakefulness, and that all the images and lamentations which sleep has suggested to the poets, would have been lost. He who assumes that a certain portion of excitability is originally assigned to every living system, by his very assumption, denies its continual production, subsequent diffusion, and expenditure at a rate equal to the supply, or greater or less. That the brain is an organ destined to secrete the matter of life, he could never have supposed, otherwise he would not have expressed a doubt whether excitability be a quality or a substance.

If we admit a successive supply of this principle, we may solve in a very easy manner, several difficulties, for the sake of which new epicycles must be added to Brown’s system. In the cold bath we may imagine the generation of sensorial power, to proceed with small diminution, while the actions on the surface of the body are considerably abated by local subduction of heat. Thus the well-known glow will be the effect of undiminished production within, while external expenditure is diminished. But weak persons frequently do not experience any glow.

Here the action on the skin affects the system universally; the production, therefore, is checked from the torpor of the secerning [distinguishing] organ, and this state of the brain explains the head-ach and chilliness, subsequent to the misuse of the cold bath. These effects are not, in my apprehension, easy to be reconciled to the hypothesis of a fixed original stock of excitability; the same thing may be said of seeds and eggs long preserved, without sensible change, in a state capable of germination and growth.

Sleep sometimes produces no refreshment, and yet it seems not to be imperfect or disturbed in proportion to the languor felt on awaking. This I have attributed to a failure in the supply of excitability; and nervous fever is imputed by another physiologist, to this cause of debility, of which Brown had no suspicion. —

If an illustrative analogy be desired, his excitability might be compared to a fluid lodged in the body as a reservoir. According to the statement which I think more consonant to the phaenomena, excitability would be like a fluid issuing from the brain as water from a spring. These resemblances might be traced a little way, but they soon fail, as always happens in matters so essentially dissimilar.

The hypothesis of Brown is happily adapted to the limited term of life; according to the other supposition, we must conceive old age and death to depend upon a limited power of secretion in the brain. The difference is scarcely perceptible here, but in terms; it is, however, pleasing to suppose that wiser ages will be employed in the culture of the human species to which prolongation of life is essential: and we can more easily reconcile our thoughts to augmentation of power in a secerning organ, than of the original provision of excitability; so that the doctrine, in other respects the more probable, seems more conformable to the prospect of improvement.

John Brown’s initial two chapters in The Elements of Medicine: [**]

The Elements of Medicine
The First and Reasoning Part.
Chapter I

Of medicineOf health, good and illOf diseases local and universalOf predisposition.

I. Medicine is the science of preserving the good, and of preventing and curing the ill, health of animals.

II. The application of this science to vegetables, may be named Agriculture.

III. Good health consists in a pleasant, easy, and exact use of all the functions.

IV. Ill health consists in an uneasy, difficult, or disturbed exercise of all or any of the functions. Diseases come under this head.

V. Diseases either extend over the whole system, or are confined to a part; the former may not improperly be called universal or general, the latter local.

VI. The former are always universal from their very commencement, the latter only in their progress, and that but seldom. The former are always, the latter never, preceded by predisposition. The former proceed from an affection of the principle of life, the latter from local injury. The cure of those is applied to the whole body, of these to the injured part.

VII. To the province of the Physician belong all universal diseases, and as many of the local, as being at first limited to a part, afterwards affect the whole body, and assume, in some measure, the appearance of universal diseases.

VIII. Predisposition to disease is that state of the body, which recedes from health, and approaches to disease, in such a manner, as to seem still within the boundaries of the former, to which, however, it bears only deceitful resemblance.

IX. These three states of health, disease, and predisposition, constitute the life or living state of animals; to which that of vegetables is not dissimilar, though more imperfect.

Chapter 2

Of lifeOf the exciting powers, external and internalOf excitabilityOf excitementOf stimuli.

X. In all the states of life, man and other animals differ from themselves in their dead state, or from any other inanimate matter, in this property alone; they can be affected by external agents, as well as by certain functions peculiar to themselves, in such a manner, that the phenomena peculiar to the living state can be produced. This proposition extends to every thing that is vital in nature, and therefore applies to vegetables.

XI. The external agents are reducible to heat, diet, and other substances taken into the stomach, the blood, the fluids secreted from, the blood, and air. How poisons and contagions come under the same view shall afterwards be explained.

XII. The functions of the system itself, producing the same effect, are muscular contraction, sense or perception, and the energy of the brain in thinking, and in exciting passion and emotion. These affect the system in the same manner as the other agents; and they arise both from the other and from themselves.

XIII. If the property which distinguishes living from dead matter, or the operation of either of the two sets of powers be withdrawn, life ceases. Nothing else than the presence of these is necessary to life.

XIV. The property, on which both sets of powers act, may be named Excitability; and the powers themselves, Exciting Powers. By the word Body, is meant both the body simply so called, and also as endued with an intellectual part, a part appropriated to passion and emotion, or a soul: the usual appellation in medical writings is system. [footnote: No disquisition is here meant to be entered into, as religion is no where interfered with, b ut left to its proper guardians.]

XV. The effects, common to all the exciting powers, are sense, motion, mental exertion, and passion. Now their effects being the same, it must be granted, that the operation of all the powers is the same. [foonote: That is, since sense, motion, mental functions, and the passions are the only, and constant, effects of the exciting powers, acting upon the excitability; and since these happen, whether one, or more, or all the powers, or whichever of them, act, the irresistible conclusion, that arises in the mind, is, that, the effect of the powers being the same, the mode of operation of them all must be the same. This mode of reasoning, which is certainly as just as it is new in medicine, will often occur, and, we trust, will stand the test of the most scrupulous scrutiny.]

XVI. The effect of the exciting powers acting upon the excitability, may be denominated Excitement.

XVII. Since some of the exciting powers evidently act by impulse, and the identity of the effect of others implies the same mode of operation; and since they all possess a certain activity; they may be denominated stimulant, or stimuli.

a. Stimuli are either universal or local.

b. The universal stimuli are exciting powers, so acting upon the excitability, as always to produce some excitement over the whole system. The appellation of universal, is convenient to distinguish them from the local.

c. The local stimuli act only on the part to which they are applied; and do not, without previously producing an affection in it, affect the rest; of the body.


[*] The Elements of Medicine of John Brown, M.D., 2 vols., trans. from the Latin by the author, ed., rev., and corrected by Thomas Beddoes, 2 vol. (London 1795), 1:cxxvi–clxviii. Back.

[**] The Elements of Medicine of John Brown, M.D., 1:1–6. Back.

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