SECT. XV.
LXVII. We shall conclude this discourse, by pointing out three capital errors, which are derived from want of proper attention in making experiments. The first is, that of taking for the effect, what in reality is the cause, and taking for the cause, what is nothing more than the effect. The second consists in taking for the cause, something that comes in by accident, and which has no influence whatever. The third consists, in between two effects proceeding from one and the same cause, taking one of them for the cause of the other. I shall give examples of these three errors, in observations appertaining to medicine, which are said to be derived from experience, because mistakes in this branch, are generally attended with worse consequences, than those in other ordinary physical matters.
LXVIII. It happens, that a man feels an ardent and extraordinary thirst upon himself, without being able to assign any apparent cause of it; he drinks water to great excess, and in a few hours is seized with a fever, or an acrid fluxion. It is common in such cases, to attribute the indisposition to the excessive drinking of water, and to apprehend, that was the cause of the disease; but this was so far from being the case, that the indisposition was rather the cause of his drinking to that excess. But I would have it observed, that I speak of an instance, in which the thirst was not brought on by any manifest or apparent cause, such as the having used any violent exercise, or having been exposed to some great heat, either of the sun or fire, or having been a long time without drinking, or having eaten something very salt. I say that agreeable to this state of the case, it is very clear, that the thirst must have arisen from some internal cause; but the question is, from what cause? Why it could be from no other, than a morbific disposition, that had begun to prevail within his body; or let us express it in another manner, and say, that it proceeded from an acrid or salt humour, which had just begun to get in motion, and by vellicating the fibres that produce the sensation of thirst, had by that means excited it. Every preternatural and extraordinary effect, demands a preternatural and extraordinary cause to occasion it; and if we suppose that the thirst was such an effect, and we cannot assign any external cause to which we can attribute it; we must conclude that it proceeded from some preternatural internal cause; which in all probability, must be the morbific disposition.
LXIX. The want of this reflection, occasions great errors to be committed in physic, for by running counter to the course of nature, you must unavoidably mistake the road that leads to the cure. The consequence of mistaking the effect for the cause, is administering as a medicine, what in reality is poison; for it is clear, that if the physician apprehends the humidity and coldness of the water to be the cause of the distemper, when in truth it was produced by the acrid, salt, peccant, or inflammatory humour, I say if this should happen to be the case, and he calculates his prescriptions to correct the humidity and coldness, he by so doing, will inflame and increase the original disorder.
LXX. This species of error, is not confined to the case we have instanced, but is capable of being extended to a vast expanse. I am much inclined to think, that all the extraordinary and vehement emotions, both of the irascible, and libidinous kind, which precede distempers a small distance of time before they make their appearance, and for which you can assign no special external cause, are the effects of those distempers, in their original stages; I mean, that in the first agitations of such cases as we are speaking of, a person is apt to fall into violent passions upon very slight provocations, such as he knows by his own experience, were never used to agitate or have that effect on him, and either immediately, or within a few hours afterwards, he is seized with a fever. People are apt to suppose, that the passion was the cause of the disease; but I say, that the disease occasioned the anger; for if this man, agreeable to his natural disposition, was never subject to such violent starts of passion, upon such, or even greater provocations, it necessarily follows, that that which he experienced upon this occasion, must have been the effect of some preternatural internal cause, which lay concealed within him, most probably the first fermentative movements of the peccant humour, which soon afterwards produced a fever. In reality, it is easy for any one to perceive, and I have remarked it many times both with respect to myself and others, that the irascible passion, is much more apt to be inflamed upon slight occasions, in those first stages, or almost insensible beginnings of such indispositions as tend to be somewhat serious, than at other times.
LXXI. I do not however deny, that the ardour of passion may excite a fever; for this without doubt, may have a great share in producing such an effect, and we may reasonably suppose that it has, and especially in such people as are of a choleric disposition; but when this is not the case, we should rather suppose, that the passion tended to augment the indisposition which followed the sudden fit of anger, and which would have made its appearance without the intervention of that anger, although it might have been attended with milder symptoms. And the same we say of anger, is applicable to sadness and fear also, for they conformable to the language of the philosophers, are passions appertaining to the irascible.
LXXII. We may reason in the same general way, upon the effects of the amorous passion. All vehement desires for ordinary objects, which frequently present themselves to a man’s view, and which are totally unusual to him, and for which we cannot assign any special external circumstance that should excite those desires, we should conclude, that they proceed from some preternatural internal disposition. The indulgences or gratifications of these extraordinary desires, are always attended with actions of excess, to which are generally attributed the indisposition that follows them; but in truth, the indisposition which laid concealed, irritated the appetite, and was the cause of the excess, and not the excess of the indisposition.
LXXIII. The following mistake also, is very frequently fallen into. A person who has always been indifferent about this or that particular food, we will say lettuces for example, all of a sudden takes a great fancy for them, and will eat two or three large ones. If he is afterwards attacked with a pain of the head, and defluxion upon the breast, or a diarrhœa, the fault is sure to be laid upon the lettuces, which are accused as the cause of all the mischief; but in reality, the mischief had before crept into the constitution, and had induced the extraordinary desire to eat the lettuces.
LXXIV. I would not however, be understood to insinuate, that eating of any thing to excess, does not frequently occasion or bring on various diseases; for I only mean that my position should be understood to allude to a desire that is vehement, and unusual to the person, and for which, you can assign no visible external cause that should excite it; for under such circumstances, there is a necessity for concluding it was owing to some internal cause, that was sufficiently powerful to merit the name of a morbific disposition; which is an appellation it could not have deserved, if the appetite although extraordinary, had not been excessive.
LXXV. I am confirmed in the truth of the remark I have just made, by the reflexion, that a diversity of appetites, must undoubtedly proceed from a diversity or alteration of temperaments; and it follows of course, that every alteration in the temperament, must be attended with an alteration of the appetite. It is easy to discern, that no sick person, preserves his appetite in the same even state, in which it continues when he is in health; and this not only with respect to the quantity he eats and drinks; but with respect to the quality of his nourishment also; nor is this confined to the objects of his palate only, but extends to those of all his other feelings and inclinations, both internal and external.
SECT. XVI.
LXXVI. The second capital error committed in making experimental observations, and which is more common than the first, is that of mistaking for the cause, something that intervenes by accident, and is neither cause nor effect. There is scarce any sick person, who does not fancy he knows what has been the cause of his disorder, which he generally imputes to something particular that he has done, or some alteration he has made in his way of living a little before he was seized with his distemper; although the thing to which he imputes it, bears no allusion to, nor any proportion with the disorder that afflicts him. The having eaten an olive more than it was usual for him to eat, or having fasted a quarter of an hour longer than his usual time, or having drunk two spoonfulls more than common, or abated twenty yards of his ordinary walking, together with some other particulars, that are equally trifling and insignificant with those we have mentioned; but notwithstanding the futility of these observations, he is apt to impute to such causes the disorder he labours under, without reflecting, that this machine of ours, from the weakness of its own texture, is sufficiently exposed to its breaks, ebbings and flowings. The humours of the body, even when the influence of all external causes, and every thing that depends on our own free will, are regulated with perfect uniformity, are nevertheless exposed to various alterations. The heterogeneous nature of them as they respect one another, and also considered with respect to every particle of each of them separately, must necessarily conduce to their being in different states. If those superstitious spirits, who are such idolaters of their health, that with respect to their own regimen they would weigh even atoms, would well consider this, they would free themselves from the continual anxiety in which they live, and which is more pernicious to them, than those very indispositions they are so terrified at, and which they are at so much pains to escape.
LXXVII. But the most common accusation of all, is that which charges the weather as the cause of our disorders. He who commits no excesses, and cannot assign any other cause for his being out of order, lays the blame upon the weather, and even he who does commit them, to avoid criminating himself, lays the blame on the weather also; which be it hot, moist, dry, variable, or settled, people are never at a loss to find out some pretence whereon to ground the accusation. If in July, as is customary at that season, we find it very hot, we say the heat is the cause of our disorders; but if the weather at that time happens to be more benign and temperate than usual, they still lay the blame upon it, alledging that such a temperature of air is not natural to the season. The same sort of charge is brought against the cold in winter, whether it is intense or moderate. If at that time of the year, the weather is variable, there is scarce any one who does not find fault with it; neither is it exempted from blame if it is settled, for then they say that change of weather is indispensably necessary to our constitutions; and that any kind of weather which lasts a long while is hostile to them; that long cold occasions constipations, long heat dissolves and weakens us, long wet suffocates us, and that long drought burns us up and consumes us.
LXXVIII. I have often remarked, that all our misfortunes are imputed to two common enemies: our spiritual ones to the Devil, and our bodily ones to the weather. There is scarce any one, who, in order to extenuate his own guilt, does not say, he was tempted by the Devil to commit the crime he has been guilty of. He is as irrational who thinks, that if there was no Devil to tempt us, we should never sin, as he is who thinks, that if the weather was regulated in a most perfect form and order, we should never be sick. Within ourselves, and in the very essence of our being, lies the origin of all our ills, both spiritual and temporal; and our nature is swayed by its own weight, towards both the one and the other evil; although we can never be led into the first without our own consent; but the other species, may frequently be brought on us against our will.
SECT. XVII.
LXXIX. The third error committed in making experimental observations, although it is not so common as the two first, is pretty often incurred. If he for example, who on account of his having used some violent exercise, drinks small liquors to excess, and afterwards finds himself feverish, imputes his being so, as is very frequently the case, to his having drank such liquids to excess; the generality of men, seldom reflecting upon any excesses, but those of the appetite; but with all this, violent exercise is much more likely to inflame the blood, and disturb the humours, than drinking to excess of small liquids, and therefore it would be much more rational, to impute the fever to the violence of the exercise, than to drinking small liquids to excess.
LXXX. I believe that from the blunder of mistaking two effects of the same cause, the one for the cause, and the other for the effect, arose the opinion, which is so common among medical people; that all fluxions wherever they fall, the gout not excepted, descend from the head; and it being very common, for those who are affected with acrid fluxions that fall on any part of the body, to feel pains and heaviness in their heads; I suppose that from thence sprung the notion, that all fluxions originate in, and are derived from the brain; but there are not a few modern physicians who are of a contrary sentiment, and in my opinion they are right.
LXXXI. In the first place, I do not know why the vicious humours, from whence the matter of fluxions are derived, should make the grand circuit through the head, before they fall on any particular part that is at a distance from it; as they could, by being mixed with the blood in their circulation through the veins and arteries, be derived immediately from them, on any member or part of the body.
LXXXII. Secondly, if such a vast quantity of humour, as is discharged by some fluxions, was to be lodged in the brain, it seems to me that it must render a man quite stupid, and that organ incapable of exercising any of its functions.
LXXXIII. Thirdly, it is not easy to point out the channel, through which the humour passes from the interior part of the head. Many pretend to say it passes through the Ethmoides, or Os Criboso; but Sneider denies this, for that you cannot find any cavities or perforations in this bone, through which those humours could flow, and especially if they are pituitous and clammy, as the antients supposed them to be; and to this we may add, that this bone is entirely covered or lined by the meninges, and the interior tunic of the nose. It is true, as Doctor Matinez observes in his treatise on anatomy, that its upper part is very porous, and that from thence it came to be called the os criboso, or spungy bone; but as these spungy pores do not pervade the whole bone, and are not pierced through it, setting aside the obstacle it would meet with from the membranes or tunics that surround it, the humour could not pass that way. If it is insisted, that it flows through the nervous ducts, I ask how it comes not to be attended with obstructions, that must produce dangerous consequences?
LXXXIV. Fourthly and lastly, that through whatever channels you suppose the humour to pass; how does it happen, that neither in them, nor the parts immediately connected with them, it does not excite any sensations, but that sore feelings, are only perceived at the part where it vents itself? Is it not totally incredible, that a very acrid humour derived from the head, and which flows to the stomach, to the breast, to the intestines, and even to the extremities of the feet, should produce no sensations in the intermediate parts between the head, and the place on which it falls? This difficulty, which occurred to me many years ago, I have often mentioned to medical people, but never could get any solution of it that was satisfactory to me.
LXXXV. If by way of objection to what I have here advanced, the argument we have mentioned before is urged, that defluxions on any part of the body are generally attended with a pain in the head; I answer, that it cannot be inferred from thence, that the humour descends from the head. In the first place, for I have observed it many times with regard to myself, these fluxions are often not attended with any pain in the head at all; and to make the inference just, they should always be attended with one. Secondly, although a pain in the head should constantly accompany a defluxion, the objection made would easily be removed, by saying, that this appearance is fallacious, for that both the pain and the defluxion, are effects of the same cause, and not one the cause of the other. In fact, reason tells us this is the case; for the acrid humour, which when separated from the mass of blood, falls on, and discharges itself at this or that place, while it continues in the circulation, has nothing to hinder it from venting some portion of its poison on the head, and exciting pain there; and especially, as it is generally supposed, the nidus of the humour which flows in defluxions, is in the glands, and the brain holds the first place in that class; for which reason, Hippocrates and Wharton, call it the great and principal gland.
LXXXVI. If it is replied to this, that in every defluxion which is somewhat violent, although we do not feel what may be properly called pain in the head, we at least perceive a heaviness in it; which renders that organ unfit for its operation. I confess that this is so, but to the confession, shall beg leave to add two remarks. The first is, that this is not a symptom peculiar to fluxions, for that the same thing happens in many other disorders; but the generality of physicians do not conclude from hence, that those diseases originate in the head. Secondly, neither is this heaviness or inaptitude, peculiar to the head, for upon observation, you will find that fluxions and many other disorders also, have the same effect upon the other members of the body. Whoever is affected with a violent defluxion, either on the throat, the breast, the stomach, or any other part, will find that his whole body, and every member of it, is more heavy and listless, than when he is in good health; and that all his limbs are less fit for action; and that they all with a very little exercise of them, become soon tired. Thus we have no reason to attribute a heaviness as peculiar to the head, in the attacks of fluxions, when we see it is common in those attacks, to all the other members of the body; and it has been for want of making this reflexion, that the world have conjectured all defluxions were derived from the head.