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.
The exhaling vessels no longer pour forth a dewy, mild, and saponaceous lymph, but they throw out a thick glue, which affects the sick with a constant pain and sense of a heavy weight, and of cold at the stomach, and creates the utmost loathing. The consequence is the same when the intestines, being of the same structure with the stomach, suffer the same injuries: the action of respiration first begins to fail, whose alternate compressions, whilst it is accelerated by the muscular motion, compress and strain all the viscera of the abdomen; their irritability is lost, the body is generally costive; there is here likewise accumulated, a troublesome phlegm, the prolific mother of diseases. Thus it once happen’d to the celebrated Justus Lipsius, professor of history at Leyden, who being long ill, and under the care of his illustrious colleague and friend Heurnius, found no relief till he had voided a substance resembling the intestines both in figure and colour; it was a tough and viscid phlegm, gradually collected in the whole tube of the intestines, through a sedentary life wasted by study; and this phlegm, turning to putrefaction, made a jakes of the whole body. The fomes of the disease being thus purg’d off, he was restor’d to health[26].
The collected excrements compress with their bulk the neighbouring parts, irritate the intestines by their corruption, and by absorbing the putrid matter infect the whole mass of blood. From all these causes put together arise those excruciating pains in the bowels which often torment the studious, and are with difficulty cur’d, as they are perpetually renew’d by errors in diet[27]. Hence that troublesome flatulency, so hurtful to sedentary men, which torments the learned a thousand different ways, and often passes for other disorders.
The intestines are not only affected, but the functions of the neighbouring parts are disturb’d, as well from the violence of the compression as from their own diseases; the pancreatic juice grows vapid and stale, the functions of the spleen are vitiated, the repositories of the bile are much disturb’d; by its stagnation it loads the liver, forms obstructions in it, thickens and grows hard itself, and flows slowly to the intestines; whence their disorders, especially those of the jejunum, and vices of the chyle, increase; being scarce able to pass through the narrow neck of the cystic duct, it often concretes into a stone, and occasions those severe colics with which the celebrated Ignatius, founder of the Jesuits, was formerly afflicted, and with which the learned are often tormented[28]. If at length by stagnating it putrifies, it then erodes, ulcerates, inflames, and assumes the appearance of all the innumerable disorders of the liver, and produces inconceivable anxieties. These are likewise caus’d, though with less danger, by that cruel disease call’d the hypochondriac; the first species of which, mention’d above, and call’d the nervous, is occasion’d by excessive labour of the mind; the other, I mean the abdominal species, arises from a disturb’d circulation in the abdomen. With both these disorders the learned are afflicted, and therefore seldom or never live free from this evil; and, whilst one of these adds force to another, they are seldom entirely cur’d of them[29].
Considering they occur so frequently, it is hardly necessary to give examples; but if I were to cite examples, the first that would occur to my mind would be that of the illustrious Swammerdam, that sagacious inquirer into nature, who was so full of atrabilary humours, that he scarce vouchsafed to answer those who spoke to him, but look’d upon them with an unalter’d countenance; and, when he took his seat as professor, sat with a face of astonishment, and made no answer to the objections of his opponents. Finally, having, before his death, wasted away with a phrantic melancholy, he burn’d all the manuscripts he had by him in a fit of madness: being reduced in appearance to a skeleton and the mere figure of a man[30], he died at length of a consumption.
It has indeed been observ’d, that this species of melancholy in some measure promotes learning, by increasing the penetration; for, whilst melancholy men are intent upon one idea only, the mind contemplates this object alone, and considers it on every side; nor is it distracted by other pursuits. But who ever proceeded to this pitch of madness, as to desire to purchase an increase of discernment at such a price? Of what advantage is science without health? He knows too much, who is render’d unhappy by his knowledge.