Part 2

Thus render’d unequal to the task of study, the learned are at last under a necessity of quitting their belov’d pursuits; for, as the strength of their nerves diminishes, their attention fails, the memory begins to lose its tenaciousness, the ideas are obscur’d, and an uneasy sensation of heat over the whole head, a dreadful palpitation, the most extraordinary weakness, and a groundless fear of approaching death, oblige them to discontinue their application. Their strength being at last repair’d by rest, nourishing aliments, and exercise, they renew their assiduity in study, but are soon oblig’d to quit their books as before. Thus the whole day is lost; and when evening approaches and they retire to bed, their weakness and anxiety make them pass their nights most dismally, whilst the great mobility of their nerves prevents their sleeping, and sometimes increases to such a degree as totally to deprive them of the power of thinking. I know a young man, upon whom an intense application to study had this extraordinary effect, that, if he read even a few pages, he was torn with convulsions of the muscles of the head and face, which assum’d the appearance of ropes stretch’d very tight.

Nor does too intense an application produce only slight and transient convulsions of the muscles; it likewise renews and generates the most dreadful nervous disorders. GALEN[13] mentions a grammarian, who was seized with a fit of the epilepsy, whenever he meditated profoundly, or taught with vehemence. I myself have seen instances of it. And the illustrious VAN SWIETEN laments the case of youths of the brightest hopes, who have been seiz’d with a dreadful and incurable epilepsy, upon being compell’d by severe masters to apply to their studies with scarce any intervals of relaxation. HOFFMAN[14] makes mention of a young man, who, as often as he weary’d out his memory and his genius by attentive study, was seiz’d with a momentary epilepsy, a palpitation of the heart, and a trance; but when he remitted of his assiduity, was always tolerably well. This the celebrated PETRARCH likewise unhappily experienc’d, being seiz’d with an epilepsy through his great application to study, to which he was immoderately attach’d. In a public promotion, one of the candidates for literary honour, after having pursu’d his studies with the moil arduous application both day and night, through a too great attention to his oration, that he might be able to say it accurately by heart, was suddenly seiz’d with a catalepsy and fell down[15].

The labour of the mind not only produces nervous disorders, but, by means of the nerves, gives rise to other complaints. An eminent mathematician, who was troubled with an hereditary gout, and had always liv’d soberly and chastely, hasten’d a paroxysm by applying a long time to the solution of a difficult problem[16]. And the case of the chevalier DE PERNAY is very extraordinary. After four months of the closest study imaginable, and without any previous disorder, his beard fell first, then his eye-lashes, then his eye-brows, then the hair of his head, and finally all the hairs of his body[17]. Did this proceed from the great relaxation of the roots, from which the hairs grow; or from the want of nutrition? Certain it is, that an intense application of mind relaxes the whole corporeal frame, and prevents all nutrition for two reasons; for this is the effect of thought, not upon all, but upon most constitutions, that it accelerates the pulse, and produces a fever, which, by dissolving the nourishing jelly of the fluids, occasions paleness, leanness, consumption, and a sort of wasting of the nerves; on the other hand, the cessation of the action of the nerves, is capable of producing it. Nor does it less cease in the whole body, whilst it is obstructed by application of mind, than when it is stopped by a swelling or a ligature in any part. We should not be too inquisitive in prying into causes; and many circumstances relating to nervous disorders will for ever remain unknown: but if any one should be curious to know how the too great tension of the nerves is hurtful, I will briefly give him my sense of the matter. The body is exhausted by too great an evacuation; hence arises weakness, an extraordinary tenuity of the humours, and, what it is generally productive of, a diseased mobility. Suppose the blood were to run copiously from a wound, or the gastric fluids were to be pour’d forth by the anus, or the breasts suck’d too long, or a greater discharge of saliva made by spitting, or the wretched body were to be troubled with a long diabetes, or in short, any other evacuations were too much increased, the strength would decline, and the health be lost; but whilst the nerves act, their fluid runs out of the body, and carries off the strength with it; nor is there any thing in the body either more labour’d, more necessary in many animal functions, or more intimately connected with strength. In studious men, therefore, a perpetual dissipation of the nervous fluid springs from the incessant action of the nerves, attended with weakness, and an extraordinary mobility, from whence all the above-mention’d diseases easily take rise; these are very dreadful, but diseases still more dreadful remain to be describ’d.

It is not easy for the mind not to throw out at will such motions as it has powerfully conceiv’d; and this is a second cause of the diseases of studious men, from whence spring so many errors and wanderings of the mind, to be chang’d for death only, so many phrenzies and deliriums: for whilst ideas no longer answer to their external objects, but to the internal disposition of the brain, the latter being agitated by its own motion, either entirely, or in part, is unable to receive new vibrations, to be transmitted, all, or some, by the senses; whereas those that are spontaneous cannot be check’d.

The brain of BLAISE PASCHAL was so vitiated by passing his life in the laborious exercises of study, thought, and imagination, that certain fibres, agitated by incessant motion, made him perpetually feel a sensation, which seem’d to be excited by a globe of fire being plac’d on one side of him; and his reason being overpower’d by the disorder of his nerves, he could scarce banish the idea of the fiery globe being actually present. SPINELLO painted the devils thrown from Heaven by the Almighty, and gave so fierce a countenance to Lucifer, that he was struck with horror himself; and during the remainder of his life, his imagination was continually haunted with the figure of that demon, upbraiding him with having made so shocking a portrait of him. There are many others, whom the force of genius too much rous’d, has for ever hurried beyond the boundaries of truth. GASPAR BARLÆUS, who was at once an orator, a poet, and a physician, was not ignorant of this danger, concerning which he admonish’d his friend CONSTANTIUS HUYGENS[18]; but being blind with regard to himself, he by immoderate studies so broke the force of his sensorium, that he thought his body was made of butter, and carefully shun’d the fire, lest it should melt him, till being at last tir’d of his excruciating fears, he leapt into a well. I must still grieve for a friend of a penetrating genius, an excellent understanding, of strict morals, and one that seem’d born for a better fate; who being animated with too great a love of learning, and in particular of the medical science, by reading night and day, observing, making experiments, and meditating, at first became sleepless; then began to talk, sometimes incoherently, and sometimes rationally; at last run mad, and having scarcely escap’d with life, never recover’d his reason. I have known many others, who by study alone were first rendered phrantic, or crazy, and at length became idiots. I love, esteem, and honour an illustrious man, and a man of extraordinary abilities, who being twelve hours intent upon settling a difficult memorial, after having finish’d his work, became delirious till a soft sleep quieted the state of his nerves. Observers give us accounts of many similar cases, and I was inform’d by a witness who may be confided in, that PETER JURIEU was formerly famous for his talent at disputing, by his labours in writing books of controversy, and expounding the apocalypse, so disorder’d his brain, that though he thought like a man of sense in other respects, he was firmly persuaded that the seven fits of the cholic, with which he was tormented, had been occasion’d by a constant fight between seven horsemen that were shut up in his bowels. There have been many instances of persons, who thought themselves metamorphos’d into lanterns, and who complain’d of having lost their thighs.

But those are affected in the most dangerous manner, who dwell too long upon one and the same thought; for thus one part of the sensorium being longer stretch’d than the rest, without being ever reliev’d by the others in their turn, is the sooner broke; for as the body suffers more if one or but a few muscles alone act, so the brain is the less fatigued when various parts act successively; the part which discontinues recovers its strength, whilst the others are at work; and that is durable which does not want alternate rest.

Many years ago I knew a woman, who appear’d to have very good sense for five and twenty years; but having, unhappily for her, embrac’d the sect of the Herrenhutters, she became entirely inflam’d by the love of our blessed Saviour, and of him alone; and she dwelling entirely upon this idea both day and night, it so broke the tone of her brain, that in a few months time she became an idiot; but still she was so mindful of her Lamb, that visiting her every day for half a year together, and frequently addressing my discourse to her, I could never hear any other words from her than _my sweet Lamb_; and this she utter’d every half hour, with downcast eyes, and was the only word she spoke for a year and a half; which time being elapsed, she pin’d away and died. And to pass by other examples, there was not long ago in this academy, a young man of bright hopes, who being too earnestly solicitous about squaring the circle, died mad in the Paris hospital.

The third cause of the disorders of the brain, is, that law to which the human machine is subjected; that a new quantity of blood should be added to the part that acts. The illustrious MORGAGNI knew a man of learning at Boulogne, who whenever he gave his mind to abstract meditations in the morning, before he rose, was sure to bleed at the nose for a short time after[19]. Therefore as often as the brain increases its action, it is moisten’d with an additional quantity of blood, which, giving a new tension and a quicker motion to the vessels, brings on both the sense of pain and heat already mentioned, and many more grievous symptoms; namely, according to the different state of the brain, of the blood, and external objects, it occasions dilatations of the veins and arteries, obstructions of the nerves, inflammations, suppurations, scirrhous tumours, ulcers, dropsies, and thence head-achs, deliriums, drowsiness, convulsions, lethargy, apoplexy, and continual obstinate watchings, which cruelly torment the studious, and afflict them with new diseases; for what diseases, what perturbations of the mind do not protracted watchings give rise to? The great BOERHAAVE was six weeks without sleep, after profound study and meditation; and at the same time so indifferent to every thing, that scarce any object whatever affected him[20]. And which of you, learned auditors, has not found by experience, that a slight and disturb’d sleep, a sleep that scarce gives refreshment, generally follows a day pass’d in study. A slight irritation of the brain causes want of sleep; from one more considerable arise convulsions and drowsiness; from the greatest of all a mortal apoplexy, which disorder often puts an end to the lives of learned men. The reason is, that that part suffers which was guilty of the excess, and whilst the strength of the brain is relax’d by study, and fresh blood is forc’d into it, it must sooner or later be quite overwhelm’d, especially at the time that some new cause adds force to the blood that impells it; thence it has frequently come to pass, that learned divines in preaching, and learned professors in delivering their lectures, or disputing, as was the case with the celebrated CURTIUS at Leipsick, expir’d on their very chairs; and LIVY the historian has preserv’d to us the history of king ATTALUS, who died in the assembly at Thebes, whilst he was animating the Bœotians by an harangue to enter into an alliance with the Romans.

I saw a reverend pastor, who on Whitsun-sunday, after having preach’d long and with vehemence, whilst he was distributing the host to the people, was first seiz’d with trembling, then stammer’d, then was delirious, then fell down in an apoplectic fit, and continuing delirious ever after, though in an advanc’d age, liv’d for some months in a state of infancy. The celebrated MORGAGNI likewise mentions a preaching monk, who was seiz’d with a violent apoplexy before his congregation, and quickly died; his vehemence of delivery conspiring with a plethora to destroy him[21]. A professor at Berne, deeply versed in the oriental languages, a man in the prime of life, but of indefatigable industry, not long since sunk into a second infancy, and a state of idiotism, his brain being overflow’d by water, which stagnated in it[22].

We must not forget, in enumerating the injuries suffered by the brain from this overflowing of the blood, that the disorder of the nerves which causes the hypochondriac disposition, is increased; their little tubes being dilated are constantly weaken’d, grow soft, and make less resistance to impressions, which is one of the chief causes of the hypochondriac disorder.

Nor do the sufferings of studious men end here, since from another law, which holds equally in the animal œconomy, a fourth cause of the disorders of the learned springs from an over violent labour of the mind; for the animal fibre is indurated by being used, the whole machine grows callous as it grows old; the parts that are exercised by labour become hardened in workmen; the brain of studious men contracts a callosity, so that becoming unequal to the task of forming ideas, they fall into a premature dotage: thus the too great softness of an infant’s brain, and the too great hardness of a brain occasioned by study, are equally ill adapted to produce those vibrations, without which the force of thought is lost. Let the fibre be moisten’d with water, or stiffened with lime and sand, it in both cases becomes equally incapable of performing its function. At first the memory is impair’d, as GALEN justly observes, and then reason itself is disturb’d[23].

Nor is there any necessity that the mind should meditate great and sublime objects, to impair the strength of the nervous system; a too protracted use of the eyes has often given rise to innumerable nervous disorders; concerning which, the testimony of GUNZIUS is of the utmost authority[24]. And every weak man must know by experience, how much too great a use of the eyes weakens the head. Of this I have already given an example, and have often found it by experience; for when I contemplate any object a considerable time, after the fit of a fever, or any other disorder, and before my health is quite recovered, I am seiz’d with a vertigo, a sickness in the stomach, and a disagreeable listlessness of the whole body.

In order to vindicate literature from the charge brought against it, you will doubtless object, that many men of profound learning, have liv’d to the most advanc’d age, and retain’d their powers both of mind and body unimpair’d to the last. I have heard of many, I have myself seen more; nor can either you or I ever forget that truly illustrious man, that man of universal learning, who as he was worthy of it, enjoy’d general love and veneration; who was the ornament, honour, and delight of this academy for above fifty years, and whom we all with equal wonder and satisfaction saw enter upon his 90th year, without either his reason, or his senses being in the least impair’d. But all are not equally happy, and there are few men endued with such strength, both of mind and body, as to undergo such labours with impunity, if even those can be said to undergo them with impunity, who attain to that stage of life, which they perhaps would have greatly exceeded, had they liv’d in a different manner. Some men are by nature insatiable in drinking wine, others are born cormorants of books, and never glutted with the acquisition of learning: nor should it be pass’d over in silence, that almost all the learned men, who are look’d upon as its masters by the human species, all liv’d to a great age; as HOMER, DEMOCRITUS, PARMENIDES, HIPPOCRATES, PLATO, PLUTARCH, Lord BACON, GALILÆO, HARVEY, WALLIS, BOYLE, LOCKE, LEIBNITZ, NEWTON, BOERHAAVE. Can it then justly be inferred, that violent exercises of the mind are not hurtful? Take care how you draw so false a conclusion? But, as I said awhile ago, some men are born with happy constitutions for meditation, and perhaps that excellent constitution of the fibres, productive of longevity, is the same that produces great geniuses;

_Mens sana in corpore sano_,

_A sound mind in a healthy body_;

and consequently the great men, whom I have just mention’d, owed their reputation more to their extraordinary genius, than to industry and application; and prevented the ill effects of their severer studies, by allowing themselves intervals of leisure, by taking proper exercise, and by the dissipation both of business and amusement. Nor did they lead the life of abstracted students, a species of men little known to the ancients, and who took their rise first at the declension of literature, were renew’d at its revival, and may be properly compar’d to the Indian fakirs; for both bid farewell to the human race, and both of their own accord, and generally without any emolument to society, emaciate and inflict austerities upon themselves; the former by the sun, by cold, by nails, by chains, by whips; the latter by books, manuscripts, coins, monuments, and almost all by inaction, and the want of bodily exercise. This is another, and a most prolific source of the disorders which afflict men addicted to study; for the human machine was form’d and intended for action by the supreme artificer: therefore health is inseparable from action, which will be easily conceiv’d by whoever examines the human body with attention.

It consists of containing and moving vessels, contained and moved fluids: if the fibres or vessels have a proper tone, if the fluids have a proper consistence, if the motions, by which they should be continually agitated, are neither too violent, nor deficient, we enjoy a good state of health. But it should be taken into consideration, that motion is here the chief agent, for, that alone being chang’d, the whole state of the solids and fluids is chang’d likewise: if it be increased, the solids grow harder, and the fluids are compress’d; if it be diminished, the fibre becomes relaxed, the density of the blood is lessened, for the whole body is form’d of a chyle, which is softer and lighter than any part of the body, either solid or fluid, whose small particles a continual motion unites and strongly compresses; and if this motion should fail, the parts must prove deficient in their due firmness.

But the heart is the source of all the motions in the animal machine, the principle which puts the whole mass of fluids in motion, but is not alone sufficient for that purpose; wherefore nature has given it many helps, which never discontinue or remit, but the circulation becomes slower, and diseases arise from the motion of the fluids being retarded. The chief of these helps is the muscular motion, whose extraordinary force in quickening the circulation, the most ignorant surgeon every day displays to the eyes of all spectators, by an easy experiment, when upon opening a vein he bids the patient move some cylindrical instrument round about in his hand, in order to accelerate the emission of the blood: nay, every man may easily perceive in himself, how much the quickness of the pulse is increased by the motion of the body; and these are the effects of motion, it sharpens the appetite, it strengthens the fibres, keeps up a due temperature of the fluids, promotes all the excretions, fortifies the mind, and gives a pleasing sensation to the whole nervous system; whereas by too great sloth, the muscular strength is first destroy’d for want of practice; and from a neglect of exercise there springs an impotence of motion: the circulation which is carried on only by the strength of the heart and the vessels, and destitute of external helps, first languishes in the most minute vessels, and then in every part of the body; the heat decreases, the humours stagnate, and contract a vitious disposition; for some of them lose part of their density, others part of their tenuity, and they all become glutinous, and of consequence unfit for secretions; therefore what should be secreted is retain’d, the body is loaded with a mass of adventitious humours, it is destroy’d by their acrimony, the vigour of life is benumb’d, the strength declines, the blood is dissolved to water; hence arises a dropsy, a disorder in a manner epidemical to men of learning, by which the brain is often affected. An instance of this I lately saw, with concern, in an eminent man, whose case I discover’d too late, and who not by literary pursuits, but other exercises of the mind, and total inaction of body, had broke a constitution which once was robust[25].

Those parts suffer the most, which having but weak solids, they want external helps more than any others; hence those organs are most affected by inaction, which, being contained in the abdomen, perform the first digestion of the aliments: the strength of the stomach is diminish’d, the nature of the gastric fluid is chang’d, the aliments make a longer stay in it, and, not being sufficiently subdu’d by the animal force, they go through their spontaneous changes which they would have undergone out of the body. Most vegetables retain their tartness, which, by vellicating the nerves, occasions pains and convulsions; acid eructations arise, the cardia suffers pain, the throat is parched, and the teeth blunted. On the contrary, both flesh and eggs rot, and fat aliments grow rank: hence proceed putrid eructations, immoderate thirst, and continual fluxes; digestion is always difficult, troublesome, and malignant; the aliments cease to afford nourishment, nor do they any longer repair, but irritate and weaken.