Chapter VIII: Part 8

XXXVI. There is another objection to experimental observations, which is not more reasonable, or better founded than that we have just mentioned, which is made by some superficial schoolmen, who say, that these sort of enquiries, do not require reason and perspicuity, but only eye-sight, diligence, and memory; on which account they condemn them, as things not well calculated for the exertion of invention, and ingenuity. But how little do these people know of the nature of those physical experiments, or of the manner in which they are made, which have employed the attention of so many learned and sublime spirits, of France, Italy, England, and Germany. In order to discover whether any deceitful appearance has crept in, they repeat every experiment many times over; and invent many ingenious methods of examination, to find out, whether the phenomenon proceeded from that cause, which at first sight it seemed to be derived from, or whether it was the effect of some accidental, or occult one. They make exact and nice combinations of their experiments, and invent ingenious methods of comparing them one with another, and then weigh in a most delicate balance, both the analogies, and the differences between them, in order to derive with almost mathematical certainty, the consequences to be deduced from them; and they peep into those crevices of nature that are nearly imperceptible, that they may discern through them, her inmost secrets; and I beyond comparison, find more delicate ingenuity, and more perspicuity, in many of the experiments of the famous Boyle, than I do in all the abstractions, and reduplications, of the most subtle metaphysicians.

SECT. X.

XXXVII. It is certainly and indispensably necessary, to make experimental observations with the most exquisite attention, in order to avoid our being deceived by them, as our forefathers have been, and as many people are at this day; who, confiding in a superficial and careless experiment, have precipitated their conclusions, and without giving themselves time to reflect, have deduced consequences, from the first information of their senses. From the ascent of the water in the pump, by considering the thing inattentively, was inferred the repugnance of nature to a vacuum. To what labours did Torrizeli, Pascal, and other sublime geniuses submit, what a variety of experiments did they make, and with what ingenuity did they combine and compare them, in order to undeceive the world, and convince mankind, that the true cause of this phenomenon was the weight of the air!

XXXVIII. From the flame flying upwards, was inferred the chimerical region of fire, immediately adjoining to the heaven of the moon. In our essay on Physical Paradoxes, we related the ingenious experiment with which my Lord Bacon proved, that the flame did not ascend from any natural propensity it had to fly upwards, but because it was compelled to it, by the lateral pressure of the air.

XXXIX. I was once in conversation with some school philosophers, and our discourse happening to turn upon physical matters, I took occasion to propose a question to them, which was, whether cold water (and the same may be said of every other liquid) was more subtil and penetrating than hot, which it seemed evidently to be, by the following experiment, that when we poured iced water to drink in summer time into a glass, we perceived the glass wet and moist on the outside, which had the appearance of the water having transuded through the pores of the glass; and as this did not happen when the water was luke warm, or in a temperate state, it was inferred that such water, was not so subtil and thin as cold. As the bystanders seemed converts to the force of the before-named experiment, it gave me a good deal of trouble, to undeceive and convince them of their mistake, although at length I accomplished doing it, by making it evident to them by various most clear experiments, that the moisture which adhered to the outside of the glass, did not transude through its pores, but that it consisted of the coagulated vapours, of the circumambient air, which being in a warm state, condensed and were converted into water, upon their coming in contact with any very cold body, and that they became more condensed the less porous this body was. For this reason, the vapours that are raised by fire, condense as soon as they come to the head of the alembick; and for the same, if we breathe upon a bright iron bar, or any other metallic body, that has a smooth or polished surface, and is very cold, the vapour we breathe from our mouths, when it comes in contact with that body, will condense, and adhere to it; and it is also for the same reason, that in frosty nights, we see the inside of the glass of windows moist, when they are dry without, which appearance, I have known surprise many people, who thought that that humidity was a portion of the external air, which had penetrated through the glass; and it is likewise for the same reason, that our breath, and the breath of other animals, is visible in cold weather, it being then sufficiently condensed by the circumambient air, to make it become apparent. But the most convincing argument I made use of in the dispute, and which I advanced as a conclusive one, was, that if you covered the exterior superficies of the glass with paper, there would not the least moisture adhere to it, in the whole course of a frosty night, and it is clear that the paper is not impenetrable to moisture, but can only prevent the external air, from coming immediately in contact with the glass.

XL. As it relates to the subject of the impenetrability of glass by liquids, I cannot forbear in this place taking notice of another very common error, which has originated from drawing conclusions hastily from experiments, without making proper reflexions on them. It is generally believed, that the zest of the rind of a lemon penetrates through glass, which opinion is founded on the persuasion, that if you press out the zest on the outside of a glass, the liquor that is within will taste of it. I concluding this penetration to be impossible, after meditating upon the matter, easily discovered the cause of this error; which is as follows, upon pressing out the zest, some of the particles are apt to fly and rest on the edges of the glass or very near it, and adhere to that part, which in drinking the lip is applied to; and thus the palate perceives the taste of the zest, which is communicated to it, from the edge of the glass. To determine whether this was not the case, I squeezed some of the zest in the ordinary way against the outside of the glass, and then turning it half round, applied my lips to the opposite side, and did not perceive the least taste or flavour of the zest of the lemon. And it will happen the same to any one, who will give himself the trouble to make the same experiment.

SECT. XI.

XLI. The evidence of our senses alone, then, is not sufficient to enable us to derive just conclusions from experiments; for caution, reflection, judgement, and reason, are always necessary; and sometimes in so great a degree, that all the exertion of human talents and ingenuity, is not equal to an adequate examination of the phenomena. Sir Isaac Newton, an Englishman, who was a genius of the first rate, and a member of the Royal Society of London, in the beginning of the present century, published various tracts upon optics, in which, he displayed a great novelty to the philosophers and mathematicians; that is, that all colours exist and are contained, actually and formally, in the rays of light; which are constituted of heterogeneous particles, of unequal refrangibility. He proved this singular opinion, with many experiments of exquisite invention, contrived and considered, with no less exquisite delicacy, and in fact, made more than a few converts to his opinion in many parts, but more especially among the English mathematicians; and a Mr. Gauger who was one of these, enforced the Newtonian doctrine, with a great number of additional experiments; but in a short time, one Senor Rizetti, wrote against this new system, and stated many experiments in favour of the old opinion, and even pretended, that those which had been quoted by Gauger, militated against the Newtonian sentiment. Gauger replied to this, and paid Rizetti in his own coin; that is, he not only defended the consequences which he deduced from his own experiments, but turned those derived from the experiments of Rizetti against the doctrine of the Italian. It is certain that experience, as applied to many objects, opens a most extensive and fertile field for exercising the ingenuity of man, and that nature, even to him who seeks to know her in that way, is in various instances impenetrable and inaccessible.

XLII. But we should acknowledge that in general, the difficulties are not so invincible, as not to be surmounted by reason and industry, and that the deceptions which sometimes result from experiments, proceed either from the want of proper diligence and attention in making them, or from the want of adequate ingenuity, to judge of, and decide upon them.

XLIII. This is very frequently the case with respect to medicinal observations; and from hence springs that enormous disagreement, with respect to the opinions that are alledged to be founded upon them. One says, that he has experienced the efficacy and salutary fruits, of such a medicine, in such a disease; and another insists, that he has administered the same medicine, in the same disease, and under the same circumstances, and found it to be pernicious. One of the two must be mistaken, and I believe it is not very uncommon for both of them to be so; for it might possibly happen, that the medicine neither did good nor harm, and that the administration of it, was a mere matter of indifference, and the thing itself what we call a chip in porridge. But from what could this difference of sentiment and assertion arise? Why from one of them seeing that his patient, after administering the medicine to him grew better, and from the other perceiving, that his after taking it grew worse; although it might possibly happen, that neither the one grew better, nor the other grew worse in consequence of taking the medicine, but from a very different cause. The diseases of the two patients, from their different constitutions, or internal temperaments, (which is for the most part, a thing impenetrable to physicians) might be in such a state, that the one was disposed to abate, and the other to increase.

XLIV. And although the patients may be numerous, with respect to whom this experience is alledged; and admitting that they neither all die, nor all recover, every one according to his pre-occupation, will impute to the remedy, either the happiness of those who did well, or the misfortune of those who perished; and unless they shall resolve, to make a computation of the good or bad success of the practice of those who use that medicine, with that of those who never administer it, and compare them carefully together, this doubt will probably never be cleared up.

SECT. XII.

XLV. This inattention, is without doubt what produces, and what keeps up in the world, men’s estimation for an infinite number of useless things, on which they bestow the noble epithet of remedies; and this false notion, has filled the medical books and the apothecaries shops, with an infinite deal of trash, the reading of which fatigues the memory; and the taking of which, ruins the health and constitution of the patient. You will find accumulated in them, a great number of remedies for slight diseases, which if left to nature, would cure themselves; and although all practitioners do not approve of the same remedy for the same disorder; does this prove, that the patient of each got better by taking this or that thing? I say does this prove it? for neither the imprudent sick person, nor those about him, hardly ever reflect, that there were many others besides him, who were affected with the same disorder, and who without taking any medicine at all, recovered as well, and as quickly as he did?

XLVI. A benign or favourable sort of catarrh, as is very frequently the case, becomes epidemical in a city; for which, some call-in the doctor and take medicines, and others do not; and such is the blindness of those who have had advice as it is called, that they believe they owe the recovery of their health to the doctor, although they evidently see, that all those recovered as well as they, who had no advice, and who took no physic.

XLVII. The delicate fine lady, who whenever she feels a slight pain in her head, sends for the doctor, is fully persuaded, although the pain continues for the space of twenty or thirty days, that the capital pills he prescribed for her, removed it; but it does not occur to the poor lady, that many of her friends and neighbours, who at times have the same sort of pains in their heads, and who take nothing for them, get well as soon, and frequently sooner, than she with the help of all her pills.

XLVIII. It is very common for those who have pains in their teeth and jaws, (and I say the same of all those affections which come and go of themselves,) to fancy, and give the preference to a particular remedy, which they are of opinion relieved them; but it is proper to observe here, that every one applauds his own, and reprobates as insignificant, that which is used by other people. From whence does this arise? some will say, that as peoples temperaments are different, it may happen, that in the same species of complaint, the remedy which does good to one man, may have no effect on another; but this is a common and inefficient evasion, and such a one, as overturns and levels to the ground, the use of all medicinal applications; for if this was the case, as all individuals have distinct temperaments, no less than distinct faces, it would be necessary to contrive a distinct medicine for every single individual, and in all his disorders, to apply particular remedies, different from those, which in the same species of complaints, should be administered to every other person.

XLIX. The cause then of this opposition of sentiments, is most probably as follows. The first time a man is attacked with a pain in his teeth or jaws, it is very common for him to make use of various applications, for besides those which are ordered by the doctor, all those who have felt the same pain, recommend, some one thing, and some another; and as the sensation is acute, the poor patient anxious to be relieved, proceeds in succession, to apply all those remedies, at length, perhaps at the end of eight, ten, or fifteen days, the pain abates; and as there is not one of those days, in which the patient has not made use of one or other of these receipts, happy is that which he used the last; for to that he attributes his relief, and reprobates all the others as insignificant. Another diseased person, proceeds to take his medicines in regular order; but the course of this regulation, frequently depends upon the casual concurrence in opinion of the people who are consulted, or the power that one of them has of prevailing over, and leading the rest; from whence it frequently happens, that this man of persuasive eloquence, advises the using a medicine in the first instance, which some other practitioner might think it advisable to administer last. The result of which is, that in case the patient does well, his recovery is imputed to the application of the last remedy; and hence it comes to pass, that one reprobates a medicine which another applauds, and so _vice versa_. Thus all the reputation the remedy acquires, be it what it may, depends upon the casual application of it, just at the time nature was disposed to terminate the disorder by a favourable crisis, and hence it is, that the relief came to be attributed to the medicine. And notwithstanding that afterwards, upon another occasion, by using the same medicine in the first attacks of the same complaint, they did not experience the same effects from it; still the same prepossession is continued in its favour, that was formed on its supposed success on the first trial; and although the patient, did not find himself better for several days after taking it in this last instance, they persisted in imputing his recovery to the favourite receipt, and in thinking that without the assistance of it, the disease would have been more tedious, and more severe. Nor is it of any avail to remove this prejudice, their seeing that others, who neither make use of that or any other remedy, do not suffer more prolix, or more acute pain than those who apply it; for although they see they will not perceive it; and if they do perceive it, they will not attend to or acknowledge it.

SECT. XIII.

L. There is a certain delusion, that is very fortunate for the apothecaries, and very fatal to the sick, that is derived from a persuasion in many of these last, that their diseases would be eternal, or incurable, without the help of medicine; although they see every day, others cured of the same diseases, without this aid; and although the disorder was of so slight a sort, that all those who did nothing but leave nature to itself, recovered from it, he who called in a physician, upon his getting well, thanked the doctor for his cure, when in reality, he perhaps did nothing but delay it. I protest that when catarrhs have been epidemical, I have in various instances observed, that they lasted as long with those who took medicines, as they did with those who took none; and the only difference that I could perceive between them was, that the last recovered their natural state of robustness as soon as the catarrh left them; and that those who had taken physic, did not recover it till several days afterwards.

LI. There is another mistake said to be built upon experience, under the deception of which, many shelter themselves, and pretend, in opposition to those who differ from them in opinion, to justify the necessity of plentiful evacuations. The rigid Helmonists, or sectaries of Van Helmont, reprobate as prejudicial, purging and bleeding, in every case whatever; and in opposition to this doctrine, is urged the common experience, deduced from the cases of an infinite number of patients, who have been purged and blooded, and have all done well; and that there have been some weeks in sickly times, in which one physician has ordered a hundred patients to be purged, and as many to be blooded, and that not one of them has died. How then in opposition to this experience, say the Galenists, can any one pretend to insist, that bleeding and purging do harm?

LII. I do not undertake to defend the Helmonists, nor do I consider their opinion, as more probable than the contrary one; but I say, that from the experience alledged, nothing can be concluded to their prejudice. We should suppose, that those who exclaim against purging and bleeding, do not think them so pernicious, as to be fatal to all those who undergo these operations; for even supposing them to be injurious, they are not capable of destroying a man in perfect health, nor one that is visited by a slight disorder. I believe, that although an intemperate use of them kills many, they are chiefly those who are affected with some obstinate disease; for in these cases, when nature is much weakened by struggling with a powerful disorder, if you add a fresh enemy for her to encounter in the imagined remedy, you compleat her overthrow, and lay her prostrate on the earth. But those who are affected with a disease that is not dangerous, (and there are many of this sort, which in appearance seem violent ones,) generally preserve a sufficient degree of strength, to resist both the distemper, and some unnecessary bleedings and purgings; and although these may weaken the natural faculties, and retard the cure, they very seldom are known to deprive the patient of life.

LIII. That the number of mild disorders, greatly exceeds that of the dangerous ones, is very plain and certain; what then can we find extraordinary, in those who are attacked with the first sort getting well, notwithstanding they may have been injudiciously purged and blooded? out of a hundred patients that a physician visits in a week, seldom more than one or two of them labour under dangerous disorders. It is customary with many people to send for the doctor, upon being attacked with a slight inflammation, a catarrh, an ephemeris or fever of a day, a fluxion of the eyes, a repletion of the stomach, and such kind of indispositions; and if he happens to be one of the common or vulgar sort, he seldom fails to purge and bleed. But admitting that the purging and bleeding were never so improperly administered, does it follow from thence, that the patient must die? Or why should this be an unavoidable consequence, if in the same situation, he had been stabbed with a poignard that had not penetrated very deep, or that had not wounded a vital part, he would have escaped with his life?

LIV. As I observed before, I am neither a partizan of the Helmonists, nor a favourer of the Galenists; but I look upon it as a thing certain, that an intemperate use of purging and bleeding, has destroyed many men, and especially, if administered when nature is much weakened; notwithstanding which, I am persuaded that they are serviceable in many cases. Whether they are absolutely necessary, and whether patients could not do well, if other remedies were substituted in their places, is a point I will not take upon me to determine; and especially, when I have fresh in my memory, the declaration of a physician, whose authority has great weight with me. This is Lucas Tozzi, a famous Italian physician, who in his exposition of the third aphorism of the first book of Hippocrates, _Habitus Athletarum, &c._ after combating and controverting the usefulness of bleeding, with seemingly very efficacious and persuasive reasoning, he asserts, and offers to prove, that it is not necessary in any one of the diseases, in which the Galenists insist it cannot be dispensed with; and in answer to the experience they alledge of its utility, he quotes his own; and says, _if they appeal to experience, and insist that it is evident from thence, that many people have been cured of various disorders by blood-letting; I reply, that in the hospital of the Anunciada at Naples, where I have officiated as physician many years, I have cured in a short space of time, and without taking from them one drop of blood, hundreds and thousands of patients, who have been attacked with some one or other of the following disorders, frensies, pleurisies, quinsies, inflammations of the liver, spitting of blood, erysipelases, and all kinds of fevers_.

LV. What shall we say to this? Lucas Tozzi was not only a great theorist, but also a most expert, successful, and much esteemed practitioner, and as such, his advice was solicited with anxiety by people of the first rank. If he without bleeding cured all those disorders, which in the common opinion stand most in need of that evacuation, and not only cured them, but did it in a short time, what diseases must they be which cannot be cured without blood-letting?

LVI. And it is very remarkable, that in the same manner the Galenists endeavour to deduce from experience the necessity of blood-letting in many diseases, they endeavour also to establish the preference, that should be given to drawing blood in particular disorders, from particular veins, such as the hepatic, and cephalic. Anatomy however, makes it as clear as the sun at noon-day, that this preference is not grounded on any solid foundation, and that the cephalic vein bears no more relation to, nor is any more connected with the head, than the hepatic, nor the hepatic with the liver, than the cephalic; and that all the veins of the same arm, communicate indifferently with all parts of the body, as the laws of circulation demonstrate; and as that observation which was pretended to be derived from experience, was founded in mistake, it is not improbable, that that which is generally alledged in favour of bleeding, may be so likewise.

LVII. What appears to me is, that the rule so much cried up by the Galenists, and which establishes the necessity of bleeding, in pleurisies, is liable to so many exceptions, that we ought not to regard it as a general one; and we have observed in another part of our works, that in some epidemical pleurisies, it has been found to be evidently injurious. It is but a little while ago, that a learned French physician, whose works are mentioned in the Memoirs of Trevoux, wrote strongly against bleeding in winter pleurisies and peripneumonies; and his reasoning had great weight with some eminent physicians of Paris. I can certify, that in the last winter 1731, when many people were attacked with pleurisies in this country, it was generally remarked, and we received informations to the same effect from all quarters, that those who were blooded died, and that those who were not did well.

LVIII. I would have it understood, that I wish all I have said, with respect to the utility or inutility of purging and bleeding in general, should be considered as the sentiments of a man, who takes no side in the dispute, but who proposes what he advances problematically, and with a view of convincing the world, that in order to avoid being misled, they should examine with great attention and exactness, any observation that is alledged to be founded on experience, for this is the principal object I had in view, in writing this discourse.

LIX. It would argue weakness and want of judgment, for any one to esteem a thing as a remedy for a particular disease, without reflecting and making a remark, the propriety of which must stare every man in the face, and that is, comparing the success of the practice of those who use that medicine, with that of those who do not make use of it. There have been physicians, who have declared themselves enemies to the administration of the bark; but notwithstanding this, there is no body at this day, who disputes its febrifuge efficacy in intermittent cases; for experience shews, that it will stop the fit, although it may return again afterwards, and although in the opinion of some people, the medicine may leave some bad impression on the body. If purging and bleeding would have the same effect, in some sort of fevers, we should all agree in attributing to them a febrifuge virtue; notwithstanding that some practitioners, might give the preference to other remedies, as more safe, and better adapted. But this is so far from being the case with respect to these evacuations, that their efficacy of removing fevers, is at this day strongly contested, for experience has not yet manifested, that they are remedies for these disorders, in any degree or manner, that is not exceedingly doubtful or disputable.

SECT. XIV.

LX. As far as the nature of the case will permit us (for all things are not capable of being mathematically or decisively demonstrated), we should endeavour to discover the truth, by imitating the diligence and attention which many English physicians exercised, in examining into the eligibility of the precautionary remedy called inoculation, practised by the Turks, to elude the fatal effects of the small-pox. This is a subject, that has been much talked on in other kingdoms for some years; although in Spain we have hardly heard it mentioned. The event of communicating the infection in this way, most generally is, that the person inoculated has the distemper very lightly, and is hardly ever obliged through the whole course of the disease, to keep his bed.

LXI. The account of this precautionary method, was brought to England by one Maitland, who was surgeon to Mr. Wortley Mountague, his Britannic majesty’s ambassador at the Porte, and was from thence communicated to the other nations of Europe. Maitland had observed, that this practice was almost universal in all the cities of the Levant, and that it was attended with wonderful success. He communicated these remarks to Mr. and Mrs. Mountague, and they had fortitude enough, upon the faith of what he had told them, to make the experiment upon a son they had with them of six years old, which being attended with success, they repeated it upon another of their children when they returned to England. Many were animated with these examples and these accounts; and the practice of inoculation, began to be much approved, and much adopted in England, notwithstanding it was greatly opposed, and objected to by some people there, and by many in other countries; and especially by the physicians of Paris, who exclaimed strongly against it.

LXII. But as this contest was such a one, as ought not to be determined by speculative reasoning, an appeal was made to experience, which appeal, was prosecuted in such a manner by those who were advocates for the practice, as seemed to exclude all doubt and perplexity. Physicians who resided in different parts of the kingdom, were requested to give accounts of the success of their practice by this method, and to transmit them to London, which when received, were printed and published. By these accounts, two facts were established; the first was, that inoculation freed the patient from the danger of a second infection; and the second was, that those to whom the small-pox was communicated in this way, very rarely died; and although it is true that some few of them miscarried, they were mostly such, as were afflicted with some other disorder at the time of their inoculation, of which they would have died, if they had not had the small-pox; but these altogether, did not amount to but very little more than a tenth part of those, who perished by catching it in the natural way; for by the best calculation they could make, one out of eight died of the last, and not above one in eighty of the first.

LXIII. This is the account I have read of this matter in the Memoirs of Trevoux; to which some may object, that it is possible the relations of the cases, were not published so faithfully as they were received. To this I answer, that it is probable great pains were taken in making the enquiries, and great fidelity observed in publishing the accounts, as the Memoirs of Trevoux tell us, that upon the strength of their authority, some of the royal family of England were inoculated.

LXIV. And let it not be insisted in opposition to this, that if the fact had been so well established, it could have admitted of no contradiction. They know little of the human passions, who think this remark a solid one. Those who contradict, either through blind prepossession, or from motives of emulation, interest, or envy, seldom submit, or will own themselves convinced by proofs that are self-evident; nor is there any species of evidence, that can bar every door, at which a false subterfuge may steal in, nor against the intrusion of a thousand sophistical objections, introduced by those, who are under the dominion of the beforenamed passions. I speak feelingly of this matter, having had woeful experience of the truth of what I assert, since I first began to write for the public.

LXV. In reality, some of the objections that were made to inoculation, were the most ridiculous in the world. Some rigid Presbyterians, made the cause of religion interested in the question, and asserted, that that practice, was an affront to the sovereignty, and an opposition to the decrees of God; and one of them declared in his preaching, that it was a diabolical invention, for the devil by inoculation had communicated the small-pox to Job, which was the distemper that so sorely afflicted that holy Patriarch. Into what absurdities, does a violent ardour hurry a man in a controversy! Of all sensible human beings, there are none so nearly allied to mad men, as passionate disputants.

LXVI. Towards the conclusion of this virulent contest, a very curious circumstance came to light, which was, that this precautionary method which had made so much noise, and which had generally been supposed to have been brought from Turkey, had for ages before, been in use in the island of Great Britain itself; for that it had been practised from time immemorial, in the southern parts of the principality of Wales, where they communicated the infection in two ways either by rubbing some of the variolous matter hard on the skin of the person to whom the distemper was to be given, or else by dipping a needle into that matter, and pricking his skin with it; and as they gave the person from whom the matter was taken a small sum of money, this was called buying the small pox; and they produce very authentic testimonies, that scarce any one of those who came by the distemper in this manner died, and that there was no instance of a person who had acquired the disease in this way, ever having had it a second time.

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.