A new theory of continual fevers: Wherein, besides the appearances of such fevers, and the method of their cure; occasionally, the structure of the glands, ... are mechanically explan'd.

Table of contents

- [titlepage]

- THE PREFACE

- POSTULATA.

- LEMMA 1.

- LEMMA 2.

- THE General Proposition.

- The Particular Propo sition.

A NEW THEORY OF Continual FEVERS.

FINIS.

A NEW THEORY OF Continual FEVERS.

WHEREIN, Besides the Appearances of such Fevers, and the method of their Cure; occasionally, the structure of the Glands, and the manner of Secretion, the Operation of Purgative, Vomitive, and Mercurial Medicines, are Mechanically explain'd.

—Si propius stes

Te capiet magis.

Horat. de Arte Poet.

LONDON. Printed, and Sold by H. Newman at the Grashopper in the Poultrey, and J. Nutt, near Stationers-Hall. 1701.

THE PREFACE

TO write any thing tolerable about Fevers, or any thing worse than what has already been advanced by some one or other on the Head, is perhaps no easie matter. The ridiculous manner of accounting for their Causes and Symptoms, used by some Pretenders to Medicine and Philosophy, has perhaps contributed (in its way) to that contempt, to which (with such Expence of Satyr and Wit) they and their Art have been expos'd.

I have not the Arrogance to think the few following Sheets, will conduce any thing to wipe it off; But of this I'm sure, if this Theory prove False, the choices behind are fewer by one of the true Kind, which endeavours to account from their Appearances from Mechanick Principles.

The Wiser part of Mankind are now perswaded, That this Machine we carry about, is nothing but an Infinity of Branching and Winding Canals, fill'd with Liquors of different Natures; and I am mightily out in my Conjunctures, if for the Future any be heard about Theories of Diseases, or the manner of the Operation of Medicines, who do not reason from these Data, and their necessary Consequences. And seeing Continual Fevers, are only a Complication of Symptoms, which naturally follow upon a general Obstruction of these Canals (or the Glands which they constitute) and the necessary Effects thereof, as I reckon; None, I hope, will be angry I have call'd such a manner of Accounting for them New, seeing for any thing I know (as to the main thereof) it is really so.

For the structure of the Glands, and the business of Secretion, the Foundation is Bellini's, but I hope it has lost nothing in my hands. I have added somethings, extended others, and made all plain and consequential.

As to the other things here occasionally explain'd, which, adding what Bellini had advanc'd about Blood-Letting, make up the great and principal Operations, perform'd by Medicines on Animal Bodies; I have very frankly borrow'd what of them I found for my purpose, from Borelli, the foresaid Bellini, and another Gentleman whom I reckon the Ornament of his Profession and Our Countrey: But for the most part, pointing at Place and Person. And I shall reckon my self no more a Plagiary for this, than a Lawyer is to be accounted one for quoting his Code, or Pandects.

The occasion of entering upon those thoughts, was the noise and bustle has been made among us about Vomiting in Fevers, about a Year ago: I Endeavour'd to satisfie my self so as you may see, and had the Vanity to think there might be some as great Fools as I, If I be mistaken it's not the first time

I have not been over nice in ranging the Particulars here contain'd, those who read the whole will see their dependance, and for others I was not at the pains to lay in.

The Language is that which most easily dropt from my Pen at first writing, the Roughness of some terms of Art I cou'd not avoid, and the purity of the English Tongue is neither the growth of our Country, nor of my occasions, if it be intelligible it is all (and perhaps some may say more than) I design'd.

I neither expect nor desire any reputation from these Papers, for I sufficiently know how few such things oblige. Besides, I'm dreadfully affraid few will Read them, and not over many understand them, for want of the necessary Qualifications, of a moderate attention, and a smattering of the Mathematicks. The first is absolutely necessary, but for the latter they may even have a strong Faith, tho both for them and my self, I cou'd wish it were joyn'd with Knowledge.

As for Censure, I am in no great dread of it; For I shall lye Secure (because conceal'd) and see its adversaries (if it have the honour to provoke any) shoot at rovers. If any shall take the pains to confute what I have here advanc'd, he may do it very safely for his humble Servant, If he bungle it, he'll do me an honour, by shewing it is not such as every Body is able to disprove; If he do it to purpose he'll do me a kindness, by freeing me from my errors. I design for the future to meddle no more with it, than if it had dropt from the Clouds.

In fine, all my present concern is for the Bookseller; If he ben't a loser, (which misfortune wou'd be the most effectual confutation) it is indifferent to me, whether it perish by a particular, or the general conflagration.

POSTULATA.

1. THAT the whole Body is nothing but a Congeries of Canals, the greatest (at least a considerable) part of which is Glands, properly so called, design'd for the separation of some Fluid.

This is evident, when any part of the Body is Swell'd, so that the inconspicuous ones become Visible; and has been clearly demonstrated by Malpigius, Leuvenhoeck and oothers.

2. That when a Machine is disordered, if we should see it righted by adjusting such a particular Part, we might without scruple affirm, that it was some injury done to that part, which had disorder'd the Machine; especially, if after the whole was taken to Pieces, we should find them all sound, save that particular one.

Thus, if we should see a Watchmaker, by adjusting only the Ballance of a Watch, make her go right; we might say the distortion of the Axe thereof had occasion'd her going wrong; especially, if all the other parts be found as they should be.

LEMMA 1.

LEt there be a greater Distractile Cylindrical Canal, whose Orifice is ABCD, through which a giv'n quantity of Liquor passes in a giv'n time; and a lesser one EFGH,

through which a proportionable Quantity of the same Liquor passes with the same Celerity as in the former: Let now the greater ABCD be encreas'd or diminish'd by the lesser EFGH, So, as that in the encreas'd or diminish'd Cylindrical Canals, the same Quantities only pass, which pass'd in the same time in the first supposed Canal ABCD: To find the quantity of the same Fluid which will distract (and produce the other effects of encreasing the quantity of the passing Fluid, and consequently its Celerity) the Canal (by encreasing it's Diameter) first suppos'd, ABCD, after the same manner, only that the encreas'd (ABCD+EFGH) or diminish'd (ABCD−EFGH) Canals are now distracted.

Let the Quantity which in the first Supposition passes through the Canal ABCD be call'd a, and the Quantity which passes through the Canal EFGH be call'd b▪ Since in the first supposition the celerities are the same in both, their Orifices will be as, a and b respectively. Likewise the encreas'd and diminish'd Canals (seeing their Altitude is suppos'd the same) will be as their Orifices a+b, and a−b; and the Quantities passing through them in the same time, with the same celerity, would be likewise as a+b and a−b: But (in the second Supposition) the same quantity is suppos'd to pass in the encreas'd Canal (a+b) and diminish'd one (a • b) which pass•d in the first suppos'd Canal ABC•, or •; therefore now the quantities passing through the Canals, encreased or diminished, will be as a: wherefore, as a+b, (the Quantity passing through the encreas'd or diminish'd Canals in the first supposition) is to a; (the quantity passing through them in the second supposition) so is b, (the quantity passing through the lesser Canal EFGH, in the first supposition) to 〈 math 〉, the Proportional Quantity which passes through and will distract the lesser Canal EFGH, after the same manner that the encreas'd or diminish'd Canals are distracted in the second Position. Adding or Substracting this quantity from a, (which is as the quantity passing through, or distracting the encreas'd or diminish'd Canals) the Sum or difference 〈 math 〉 will be as the quantity which will distract the First suppos'd Canal ABCD after the same manner, &c. q. e. i.

SCHOLIUM.

THe whole Canals of the Body (save the Intestines and Lacteals) may be considered as a concave Cylinder, whose Base is the Orifice of the Aorta at its exit from the heart; and whose length is a mean Arithmetick Proportional betwixt the longest and shortest Artery (I mean the whole length of the Artery till it degenerat into a Vein; for the length of the Veins are of no consideration here) It being their splitting into Branches which makes them not Cylindrical. Now, by Postul. 1. the Vessels which make up the Glands may have any proportion of minority to the whole of the Canals; Supposing then an Obstruction or dilatation of the Glandular Vessels, it's evident the foresaid concave Cylinder will be thereby diminish'd or encreasd in any given Proportion: Suppose, e. g. the diameter of the Cylinder so Obstructed is to that of the whole, as • is to the • 2; their Orifices will be as 1 to 2. Suppose again, there are twenty pounds of Blood in a Man, seeing at the Beginning of the Arterial Vessels (which constitute the Glands) the Velocity is near the same, as proceeding from the same cause, the compression of the Heart: Therfore divide 20 into two parts, which may be (in this case) as. 1. is to 2. (which done by this general rule x=〈 math 〉, y=〈 math 〉 puting d for the 20 pounds, x for the greater, and y for the lesser proportional Part, m to n their Ratio) The Parts will be here 6⅔, and 13⅓ which are the proportional parts of 20 pounds of Blood, which would naturaly pass in the obstruct-Canal, and in the Remainder thereof which is passable. But if all the 20 pounds must now pass in the passable Canals, then it shall be distracted as much as if the whole Canals were passable; but that 30 pounds of Blood were forced through it in the same time by the preceding Lemma. For in this case a=20, b=6⅔, a−l=13⅓; and therefore 〈 math 〉=30. If the Orifices were as 1 to 3. then b=5, a • b=15 and 〈 math 〉=26⅓ this supposing an Obstruction. If there be a dilatation suppos'd in the same Proportions, then 〈 math 〉 will be in the first case 15, in the second 16. The same may be applyed to the Liquidum Nervorum, which passes in the Nervous Canals; For the Gland consists of a complicated Nerve as well as Arterie, and in an obstruction, or dilatation of the same, both Arterie and Nerve are suppos'd to be obstructed or dilated.

The design of all this is to show, that in an Obstruction or Dilatation of the Vessels, it is the same thing as if the Liquors therein contained were augmented or diminish'd in a certain Proportion; as in the case of the Bloodvessels, Supposing 20 pounds of Blood (which is the ordinary Quantity) in a Man; and Supposing one half of the whole (by an Obstruction in any place of the said) Vessels were rendred impassable, it is the same thing quam proxime, as if the whole Blood Vessels were Passable; but that one half more of Blood were forced through them in the same time, in which the 20 pounds passed. Of the same nature is

LEMMA 2.

THe Blood being so corrupted, that the strength is impair'd or encreas'd, it is the same thing as if it were in its natural estate, but that the quantity thereof were diminish'd or encreas'd in such a Proportion as is necessary for producing this encrease or decrease of strength.

This is 49th Prop. of Bellini's Book de Motu Cordis &c. and its Converse; The Proposition it self is there demonstrated, and its Converse may be demonstrated after the same manner exactly.

What is here said of encreasing or diminishing the strength, is likewise true of all the necessary effects of lessening or encreasing the quantity of the Blood. These things premis'd, I come to

THE General Proposition.

THE General and most effectual cause of all Fevers, is the Obstruction or Dilatation of (the complicated Nerve and Arterie, the excretory Duct & conservatory, one, or rather all these; which, as shall be afterward shewn, make up) the Glands, and they receive their denomination as these or those Glands are more or less Obstructed or Dilated.

Other things may concur, but these are the most powerfull causes.

It were a work of more time and pains than I can at present bestow, to apply this Proposition to all particular kinds of Fevers; tho' I am sufficiently satisfied it will account for All. I shall here only (as an earnest of the rest) show how to apply it to continual Fevers, and therefore contract the General into

The Particular Proposition.

THE most effectual Cause of continual Fevers, is an obstrution of the Glands, which will necessarily augment the Quantity of the Blood and Liquidum Nervorum, in the passable Canals and perhaps (by the Stagnation of the Fluids contain'd in these) so vitiate their nature as that they may be reckoned to concur as a partial cause of these Fevers: But I rely most on the First, to wit, the augmentation of these Fluids. For a Demonstration of this, I shall First shew how it accounts for all the appearances of such Fevers, and then subjoyn several Arguments to confirm the same.

Supposing the Glands Obstructed, the Quantity of the Blood in the Arteries, and the Liquidum Nervorum in the Nerves, may thereby be suppos'd augmented in any given proportion of minority to the whole mass of these Liquors, per Lemma 1. and its Scholium. Wherefore it will hence follow,

§ 1. That the Pulses must be stronger and more frequent than ordinary, upon these accounts 〈◊〉. Seeing there is a greater Quantity (than ordinary) of Blood in the Arteries, the Lateral Pression will be stronger; and seeing the Arteries are distractile, they will be driven outward with greater force, and make a stronger Ictus upon any thing apply'd to them. 2. Seeing the Quantity of the Blood is augmented, i. e. the Quantity of the matter whence the Liquidum Nervorum is generated, there must be a greater plenty thereof (per poster. part. Lemm. 2.) generated, and consequently it will flow more plentifully and more quickly into the heart, and make it contract oftner and more violently. 3. By the obstruction of the Gland, the influence of the Liquidum Nervorum thereinto is likewise obstructed; and therefore, per Lemm. 1. there will be a greater Quantity thereof left to flow in the passable Nerves, and it must flow qua data porta. 4. Lastly, the Arteries on every siderunning upon and touching the Medullar substance and Fibre of the Brain, will (they being more than ordinarily distended) press them more than ordinarily and make a more powerful and plentiful derivation of the Liquidum Nervorum into the places whither it can flow.

§ 2. From the same cause the inequality or Interruption of the Puises is evident: For if the foresaid Pressions upon the Nervous Fibres of the Brain be so strong, that it either partly or totally occludes the passage of the Liquidum Nervorum; there must be a stop in the derivation, till there be such a Quantity thereof collected, as shall be sufficient to over-power the Impedimentum occasion'd by this Pression, and so make an inequality or stop in the contraction of the Heart. Moreover, when the Blood flows in such plenty and with such violence from the Auricles into the Ventricles of the Heart, it may force it's way before the Ventricle be intirely Contracted, and thereby cause an irregularity in the Pulse. Add to these, what may proceed from the thickness of the Blood (it being contracted into a less space) and evaporation of its Humidity. All these, either singly or compounded, will account for the irregularities of the Pulses which have hitherto been observed.

§ 3. Great pains in the Head must ensue from the violent Distractions of the tender Vessels of the Brain, and from the great pressure of the extended Arteries upon the Fibres and Membranes thereof, all the Canals of every kind being, Bowld'ned with their Respective Liquors; and that being the most sensible place.

§ 4. A violent and Burning Heat must be felt upon these accounts, 1. Because there is a greater quantity than ordinary running in the passable Canals, there must be a greater Motion than ordinary, and consequently a greater heat. 2 Meerly upon the account of the encreased Quantity, (without considering the thereby produc'd greater Velocity) there must be felt a greater Heat. For supposing the Heat in each single particle to be the same as before; Yet since the particles are more numerous in the same Place, the heat must be greater there too: As in Rays contracted by a Concave speculum. 3. The Glands being obstructed, i. e. the passages of perspiration, the natural Heat must thereby be kept in, and consequently the whole augmented per Lemm. 1. Hence proceeds our unquenchable Thirst; the Humidity (i. e. the thinnest parts) being more ready to evaporate (since now the ordinary passages are obstructed) the rest must be proportionally dryer.

§ 5. The difficulty and frequency of Respiration, and the violence of expiration, is hence easily accounted for: The quantity of Blood being augmented, there must a proportional greater quantity thereof be deriv'd into the Arteries of the Lungs; and since every one of the little Vesicles of the Bronchi lye betwixt two Arteries thus inflated, it will be harder to explicate these Vesicles; and therefore one in such a state will naturally with all his force endeavour to suck in the Air, which will be forc'd out again, both by these inflated Arteries, and by the force of the Muscles of the Breast, Diaphragm, and Lungs; which is vastly augmented, both by the greater quantity of Blood and of the Liquidum Nervorum, and its more plentiful derivation; as has been shown in § 1. About the frequency and strength of the Pulses.

§ 6. The Tongue is rough and discolour'd, because, by the violent motion of the Blood, and the Obstruction of the common passages, the humidity is evaporated, and the extraordinary Heat stiffens the Fibres thereof. For it is evident that only heat and dryness discolour the Tongue. Vide § 4.

§ 7. Want of Sleep must follow both: Because there is such plenty of Blood, and consequently of the Liquidum Nervorum (as is shown, § 1.) that there is no need of Sleep to generate more, which is one principal use thereof: and because of diverse disorders of the Head (accounted for § 3.) which will not allow that tranquility which is necessary to bring it on; but most of all because (by the plenty of the Liquidum Nervorum) all the Muscles both involuntary and voluntary (especially those who want Antagonists) are in continual violent motions which must necessarily hinder Sleep.

§ 8. Ravings proceed from the disorders in the Head, accounted for § 3. The Nerves being distracted by the abundance of their Liquor, the Heat and dryness of their parts cannot perform these reciprocations which are necessary in sound persons.

§ 9. The clear and Flame-colour'd Urine proceeds from the velocity of the Blood, which seperates thereby only the thinest of the mixt Fluid; as shall be shown when we come to speak about Secretion.

§ 10. The vast encrease of strength, in persons labouring under high Fevers, is evident from Lemm. 2.

§ 11. Lastly, the ceasing and dissolution of Fevers by Purging, Sweating, Vomiting and Abscesses, is wonderfully accounted for from this Theory. For if they go off by the strength of Nature, then, seeing the greater Quantity and Velocity of the Blood produce a greater Momentum, by the frequent concussions and force of this, the Obstructions are shatter'd and wash'd away till the last strokes carry away all together; and thereby go off in these or those, according as these or those Glands were most obstructed. This will be better understood when we come to speak of Mercurial Med'cines. If by the assistance of Med'cines; then the Med'cines must be such as are most proper for removing these obstructions, as shall be afterwards shown.

1. Thus I think I have accounted for all the appearances of Continual Fevers; which I reckon one considerable argument for our Theory.

2. All we see done in the dissolution or ceasing of such Fevers, is the opening the Glands, the driving out the stagnated Fluids therein contained, which, per postul. 2. is another argument. And indeed one would hardly keep himself from thinking, that if the removing these obstructions remov'd the disease, then the putting them caus'd it: quo posito ponitur, & quo sublato tollitur.

3. All that is observable upon opening persons cut off by Fevers, is (the rest being sound and intire) an extraordinary Swelling and Lividity in the internal Glands; Particularly, of the Lungs, the Liver, the Spleen and the Mesentery; as has been observ'd by Borelli and others. Vide Borelli de Motu Animal. Part. 2. prop. 227. This is one ocular demonstration of our Theory; and if the other Glands were as conspicuous, I doubt not we should see the same in them.

4. A fourth Argument for our Theory is from what Dr. Pitoairne has demonstrated in his Treatise of the Cure of Fevers: For since in Fevers the Glands are obstructed, i. e. the conduits of insensible Perspiration, then by removing this obstruction, i. e. by encreasing the insensible Perspiration, Fevers will be more probably cured, than by encreasing all the sensible evacuations: And that in the proportion the number of the Glands of the whole Body has to the number of the Glands of the primae viae, or as the whole outward and inward surfaces have to the surfaces of the primae viae proxime.

5. A fifth argument is from what Bellini has demonstrated in his third and last Prop. in his Section, De Febribus. He there shews continu'd Fevers may arise from a Vitiation in the Quantity, Quality, or Motion of the Blood; from all or either of these. Moreover, from an encrease or diminution of the quantity of the Blood, there will necessarly arise an augmentation or diminution of its velocity. The motion depends upon the Quantity multiply'd iuto the Velocity, and the Quality arises (for the most part) from a Combination, or the necessary effects of these. Hence you see all that necessarily follows upon the whole three, may be accounted for from the first of these, to wit, the encreass or diminution of the quantity of the Blood.

6. Amputations, Wounds, Fractures, and the like, wonderfully confirm this Doctrine. For there, a considerable number of the Bloodvessels are stopt, and cannot make their Circle, and consequently encrease the quantity of Blood in the rest: So that generaly Fevers ensue, if the quantity be not lessen'd by letting. It is true the violent Pain may concur, since all Pain is a Stimulus, and all Stimulations occasion a more plentifull derivation of the Liquidum Nervorum. But if the quantity of Blood be not suppos'd to be augmented, that liquor must necessarily fail in a short time.

7. We may see visibly in Fevers from Cold, there is a violent Obstruction of the Glands of the Skin, the Mouth, Larynx, Stomach; In a word, of all these Glands to which the Cold Air is contiguous, and we can tell whence this Obstruction proceeds; Besides this Fever may be encreas'd to such a degree as to differ little in its symptoms, violence, or duration, from other more dangerous continual Fevers, which is a clear demonstration of our Doctrine; For since an evident Obstruction of the Glands produces Fevers so very like the most dangerous ones; why may we not conclude that some latent and unknown cause may produce so general and strong an Obstruction, as is able to occasion all the several more dangerous Fevers of this kind?

9. But that which I take to be alone (without any other Proofs) a demonstration of our Theory, is, That in all Conntrys betwixt the Tropicks, their Continual or Hot Fevers arise from a severe Cold Wind suddenly blowing after excessive Gleams of Heat This is so true, that all Travellers assign this as the cause, having constantly observ'd their Fevers to succeed such sudden changes of the Air. A pregnant Instance of which we have in Phil. Trans. For Decem. 1669 N. 259. In a Letter from Mr. Hugh Jones to Dr Woodroof, concerning some observables in Mary-Land, His words are these The North-West Wind is very sharp in Winter, and even in the Heat of Summer it mightily cools the Air; and too often at that time a Sudden North-Western Wind strikes our labourers into a Fever, when they are not caresul to provide for it, and put on their Garments while they are at work. Thus he. And indeed the genuin account of the matter is this; The excessive heat must necessarily dilate the Glands to which it is contiguous, i. e all the Cutaneous Glands, the Glands of the Trachea, Bronchi, Osophragus, Stomach, and of the Intetines; and it will not only Dilate them, but (by the assistance of the natural action of these, which is Secretion) Exhale their respective Liquors, making them still flow, so long as the excessive Heat continues, and as there is Blood which may supply them: Now they being thus dilated and (by the Efflux of their Liquors) soft'ned and made spungy, a sudden excessive Cold supervening, must strongly contract their Orifices and congeal their •…owing Liquors, and the greatness of their contraction will be always in proportion to the violence of the former Heat and supervening Cold conjunctly; as is known from the nature of Cold. And this Contraction of their Orifices and Congelation of their Fluids, will obstruct the motion of the Blood almost up to the Heart, at least to the next division of the Artery which constitutes this Gland; whereby both the Blood will be encreas'd as to its Quantity, and perhaps (by this stagnation of a part of the same) as to the Quality thereof likewise. All which is but a Corollary of our Theory.

10. Hence we evidently see the reason of the frequency of our last Years Fevers: For we were then exactly (in proportion to our Climats) in the state of those betwixt the Tropicks. Our Summer-Day heats were more violent than had been observ'd among us in the Memory of men, and our nights had no ways the Heat proportionate to our days: Besides we had often sudden changes, which tho' not so Violent as in these warmer Countreys; Yet had the same (tho' a slower) effect as among them: And therefore it was that frequent Vomitings were found so usefull, which (at least in such a degree as was found then necessary) is not always so safe. The Practice was entirely agreeable to that of these Southern Countreys, and the necessity thereof will be understood when we come to speak of Vomiting. The same practise obtains in Fevers occasion'd by surfeiting or Drunkenness; which is still to be suspected as a considerable part of the cause of Fevers in adult Persons in great Cities.

And generally I should think either the above mention'd sudden changes (which may happen a Thousand other ways different from the Season) or a direct continu'd fit of violent Cold, or excesses in Eating or Drinking; one or all of these, have a large share in most of our Continal Fevers.

11. Lastly, it is no ways accountable from any other Theory (as I think) how these Liquors which are secreted from the Glands at the Dissolution of Fevers, could be so different from the ordinary fluids which are there excern'd. From ours it is evident, for an Obstruction of the Glands must necessarily make their respective Liquors to stagnate, which will many ways alter their nature, But from any other Hypothesis I do not see how this can come to pass; which will lead me to consider one or two of the commonest Opinions about continual Fevers.

The most common and generally obtaining Opinion about Fevers is, that they are more immediately produc'd by some Morbifick matter; (like a Poison) which mixing and circulating with the mass of the Blood, Produces all those frightful Symtoms which we feel. This Opinion is sufficiently confuted, Prop. 222. 223. 224. 2dae. part. of Borelli's Book De mot. Animal. whither I refer the reader; only adding (to what he has there adduced) this one Argument.

When any Corrupt Matter is mix'd with the Blood, so as to vitiate the whole mass, (as Vinegar among Water) the way of Curing such a vitiation is either by forming new Glands to derive the vitious part of the mixture; or by draining the whole mixture good and bad, and Substituting new pure Blood in it's place: Or lastly, by disposing the already form'd Glands to secern the corrupted part.

The first of these is ridiculous.

Some thing like the second is done, when the Blood is really vitiate in the whole; as inveterate Poxes, but that cure cannot here have a place as shall be afterwards shewn.

As to the third way; let us consider,

1. How hard it is to think (when the whole Mass is suppos'd corrupted) that the vitious part, all at once, or, in the space of a few Hours (in which time we know, after a Crise, Fevers commonly leave People) should be intirely evacuated. This is not like the actions of Nature, which works leisurely and by degrees.

2. Let us consider, whence all the Glands (at least the greater part of them) should be so alter'd (seeing their configurations are so different, and naturally they secern so different Liquors) as, all at one time to separate the same Morbifick matter. And,

3. How at the Crise only, and at no other time, they should be so dispos'd.

It will be very hard in any other Theory (in this more particularly) save ours, to account for these things without recurring to miracles, or the absurd Metaphorick Terms of Sympathy, Antipathy and the like. These then, with what Borelli has brought against this Opinion in the forecited places, are abundantly sufficient to show the ridiculousness thereof.

But there are several Physicians, who observing, that, in Fevers, there was (by a Vomit) a tough viscid matter thrown out of the stomach, have thought this matter, generated there, and mixing with the Mass of the Blood, might be a considerable Part of the cause of Fevers; at least might considerably augment the same; and have from thence brought Arguments for the necessity of Vomiting in Fevers.

This Opinion supposes these things,

1. That the Quantity of the Morbifick matter excern'd by a Vomit, before the Administration thereof, was existent in the cavity of the Stomach, after the same manner that other things are, which are deriv'd into the Mass of the Blood, else it could never get thither. This I shall consider when I come to speak of the Operation and effects of Vomiting.

2. That it is at least possible, this Morbifick matter may be deriv'd into the Mass of Blood; let us at present consider this.

I know no way any thing of any tolerable consistence, can get into the Mass of the Blood; but by the Lacteal Veins. It is true, from the sudden effects of some Spirits, Medicines, and strong Meats, we are certain, that the more refin'd parts of these, may get into the Brain, without going the tedious Circle of the Lacteals: But this is done by the Reciprocal motion of the Nerves, the necessity and Mechanical Operation of which Borelli has demonstrated, prop. 155. 157. 160. 2dae. part. De motu Animalium. However, I think none will pretend such a course for this viscuous Morbifick matter: And therefore if it gets into the Mass of the Blood, it must go the common road of the Lacteals.

To decide the matter, I must suppose my Reader to have consider'd the 2 last prop. (Ex ijs quae ad separationes) which Beilini has in his Preface to his Book De Ʋrinis & Pulsibus, &c. and the 27. 28. and 40. of his last Book De Motu Cordis, &c. where the construction of the Glands and the manner of separations are demonstratively unfolded, which I take to be the noblest discovery (in these matters) of this age. From these places it is clear that,

Prop. 1. A Gland is nothing but a great many complications and circumvolutions of the Artery (all over the coats of which little branchings of Nerves pass, design'd principally for the Spiral Contortion thereof; that the Blood may be the more easily propogated through the same: But this is common to all the Arteries and Veins, whereby, without any Interruption of the same spire, the propagation of the Blood, in the former, from the heart to the extremities of the Body, and from the extremities to the heart back again, in the latter, is assisted) which sends out from the sides thereof, little Secretory Canals, which terminate in one common conduit, and is call'd the Emissary of the Gland; or perhaps in a common Pelvis (as in the Kidneys;) and the same Artery after these windings degenerates into a Vein.

Prop. 2. That separation or secretion is perform'd by the composition of two motions in the Fluid; one propagated through the length of the Canal, another transversly through its sides (for it is demonstrable that all Fluids press undiqua{que} and that the direction of their pression is perpendicular in every point to the sides of the containing vessel) The composition of which two, is the motion (or rather direction) of the separated Fluid.

Prop. 3. That in a mixt Fluid, consisting of greater and lesser cohesion of parts, of greater and lesser Fluidity: That which has the least cohesion and greatest Fluidity, is first separated (i. e. is separated in the Glands, whose compounding Artery is shortest, or at least distance from the heart, or Fountain of Motion) And these of the next cohesion, and next greatest Fluidity is next separated; and so on: The distances from the Heart being in a compounded proportion of these

Prop. 4. That the Intestines are really such a Gland, and the most visible one in the Body; whose secretory Vessels, are the Lacteals; and whose common conservatory or Pelvis, is the Recepaculum Chyli.

To these I shall add (because of its affinity) the following.

Prop. 5. The quantity separated in every Gland, is in a compounded proportion of the celerity of the Fluid at the respective Orifices; And of the Orifices themselves, of the separating Canals.

I shall here subjoyn the Demonstration of this Proposition; referring (that of) the rest to their Author.

DEMONSTRATION.

THE Orifices being given, the quantity separated is as the celerities of the Fluid: For in a greater celerity, there is a greater quantity separated; in a less celerity, a lesser quantity. The Celerities being giv'n, the quantity separated is as the Orifices directly, for at a great Orifice there is greater quantity separated, at a less Orifice a lesser quantity: And therefore neither being giv'n, the quantity separated is as the celerities, and the Orifices conjuctly, q. e. d.

From all these, I draw the following

COROLLARIA.

1. THe separated Fluids differ only in their degrees of Cohesion and Fluidity. per Prop. 2.

2. The reason why Fluids of different degrees of Cohesion and Fluidity, are separated in such and such Glands, is the different degrees of the Velocity of the Fluid at the respective Orifices of the separating Vessels, and the differences of the Orifices themselves, per prop. 3.

3. The Glands themselves differ only in the length of the Artery, the difference and number of its Complications and Convolutions, per prop. 1.

4. Each Gland (naturally and equally working) separates only the Fluid proper to it self; i. e. peculiar to such lengths and complications, of such degrees of Fluidity or Cohesion, to such bigness or smallness of the Orifices of the separating Canals; per Prop. 3. and 5. But this last is of small consideration

5. That Secretion may be perform'd the most easily that may be, the insertion of the separating Canal ought to be at an Angle of 45. degrees with the Artery, per prop. 2. For let AB Represent the Artery (if it make a Right line) or its Tangent (if it make a Curve) and let the motion of the Fluid be from A to B, the right line AB

will likewise represent its direction, propogated from the Heart. Erect at A the perpendicular AC; this will represent the direction of the lateral pression of the Fluid. Compleat the Parallelogram ABCD. The direction of the composition of these two motions will be the Diagonal AD, as is known; which in the present case, makes an Angle of 45 degrees with the Artery AB. This were well worth the observing (if it be possible) in Animals; but it must be in live ones, before their parts have alter'd their Positions. And here it were worth the examing likewise; whither what Mr. Newton has demonstrated (Scol. prop. 35. lib. 2. Princip. Phil. Mathem) about the resistance of Conical Figures, obtains in Animal Bodys; For tho his demonstration be only concerning Convex Cones, yet the same obtains in Concave ones; wherefore seeing the Artery betwixt any two Branchings is a Conus Truncatus, it may be represented by the figure CEBGF; Now seeing the Diameter CB of the base of this Conus truncatus, and the Diameter FG of the Base FDG of the Conus abscissus FDGS, as likewise their Distance, O D, may all be had; it is evident that the intire Cone CBGSH may be had likewise: Wherefore Bisect the distance OD in Q; and if it be found (having drawn CQ) that QS is equal to QC, then the Conus Truncatus CE BGF (among all of the same Base and Altitude) gives the least resistance to the Blood flowing from O to D.

I am enclin'd to think this may obtain in the truncks of the great Arteries; 〈…〉 branchings (for no further 〈…〉 considered.) This I recommend to be examin'd for the honour of that great Man, who has crouded up in this Scholium (not to mention the rest of his admirable Book) a vast number (if retail'd) of most Charming and useful Truths.

To come now to the Business; The Testiculi Humani are granted by every one, to be Glands; and Bellini has found the length of the complicated Artery in one of them, to be 300 Ells, and the Altitude of one of these Glands, (when freed of its integuments) to be 1/16 Ell: Whence I conclude, there must be 4800 Plications, or Circumvolutions in one of these, Proxime. He likewise asserts, That (caeteris paribus) if two Fluids of the same Nature, with equal Velocities, the one be forc'd into a Canal of the same Number and Lengths of Complications, as are in the foresaid Gland, and the other into a streight Canal of the same length; The Velocity (in or about their Exits) of the first Fluid, to that of the second, will be as 1 to 4800. He has not indeed subjoyn'd the Demonstration; But if we suppose the Artery to lye in Plicae or solds of such number and lengths, as we have just now determin'd; (which is perhaps not far from truth:) and if we suppose the Turnings of the Plicae to be circular; (which perhaps may follow from this, That seeing a Circle is the only ordinate figure of an infinite number of equal Sides, and equal Angles; it must be the only Curve, which can make (in all its parts) the Angle of Incidence equal to the Angle of Reflection, and consequently the only Curve in which a Fluid would most easily turn) and likewise the Arch in which they turn to be a Semicircle: (which it must be, if the sides run Parallel after the turning; and Universally, if the sides produc•d make any Angle from the quantity thereof, the quantity of the Arch in which they turn, may be determined.) I say, from these Data, the former Proportion may be by Calculation examined; or perhaps more briefly by Experiment, thus.

Take a Pipe of Metal of any Diameter, and •old it into any determin'd number of Plicae, whose sides may run Parallel, and whose lengths may be 1/16 Ell: Then by a weight force a liquor through it, and observe the time betwixt the first entry of the Liquor into the complicated Canal, and its first appearance at the other Orifice; Then take another streight one of the same length with the former, and with the same weight force the Fluid through it; observing the same way, the time of its passage, The Lengths being the same, the Velocities shall be as the time of passing reciprocally, as is known. Having thus got the Proportion of their Velocities in any one determined number of Plicae, we may (by the rule of Three) have their Proportions in any assigned number thereof. Supposing then that this great Man has found the truth of the foresaid Proportion from some such way, as one of these; follows, That in every turning, the volicity must be abated 1/4800 of the whole Proxime: (for 4800, 4800/4800∷4800 1.) Now let us suppose the Proportion of the Cohesion and Fluidity of the Fluid separated in the Testiculi Humani, to the Cohesion and Fluidity in our Morbifick matter, now deriv'd from the Stomach into the small Intestines, to be as 1 to 2. (I mean the Cohesion and Fulidity of the Fluid separated in the Testiculi Humani, as it is when immediately separated. For when it has lodg'd any time in the Vesiculae spermaticae, we know by its Ebullitions and the Evaporation of its thiner Parts, it loses a great deal of its Fluidity.) And that this is a liberal allowance, is evident from Leuvenhoek's Experiments scatter'd up and down the Phil. Trans. and Printed all together at Amsterdam; where we may see from the Microscopial Observations he has made on this Fluid, its Fluidity is little less than that of common Water: And consequently, at least, Ten times more than that of our Morbifick matter.

And here I hope it will not be impertinent, to set down a Proposition to compare the Viscidities of different Liquors.

PROPOSITION.

LET two Drops of two different Liquors fall into a pair of fine Scales; (a Drop of the one Liquor into the one Scale, and a Drop of the other Liquor into the other Scale) so that there fall no more than just their own Gravities carry down: Thus you shall have, what I here call, their Comparative Gravities; and by the ordinary Method, you may likewise have their Specifick Gravities. These being given; I say, their Viscidity and Cohesion shall be in a compounded Proportion of their Specifick Gravities reciprocally, and their comparative Gravities directly. The Demonstration is easie from the Nature of Fluids.

Let us again suppose the length of the small Guts (for it is there only where any thing is separated from the Intestines) to be 6 Yards; and that in every 1/16 of a Yard, there is a Plication: (And that these are likewise liberal Allowances; any who have ever seen a Dissection will know.) Then there will be 96 Plications in the whole; and consequently the Fluid in these Intestines, will lose but 96 parts of the whole Celerity it had at its entry.

Lastly, Let us suppose, That Celerity to be equal to the Celerity of the Blood, when it first enters the Plications of the Testiculus Humanus; (which all will readily grant, who consider, that there is never any thing found in these small Guts, but a thin Liquor in wide Canal, thrust forward by the force of the Fibres of the Stomach and Intestines) Let us call this Celerity a.

Now from Corol. 1. 2. and 3. about Separation; If a Viscidity, as 1 give 4800 Plications, then a Viscidity as 2 will give 9600 such: And therefore, that such a Viscid Liquor should be separated, it is requisite it should lose 9600 parts of the whole Celerity: But (as has been just now shown) by the Ilicae of the Intestines, the Fluid will lose but 96 parts of the Celerity a. Whence it is absolutely impossible that the Intestines should separate this Viscid matter, unless they were a Hundred times longer than they are: For 96∶9600∷1∶100. If the Viscidity of the Fluid separated in the Testiculus Humanus, were to that of our Morbifick as 1 to 10, then the small Intestines ought to be Five Hundred times longer than they are. And indeed I believe the Proportion really not to be under 1 to 50; and then they ought to be at least 25 Hundred times longer than they are.

Thus we see the second thing (this Opinion supposes,) is false; and indeed, it hardly could be otherwise; for, (in my Opinion) the Faeces themselves might more probably get into the Mass of the Blood, than this viscid matter, the parts of these being only united by a simple Contact: Whereas the parts of this are joyn'd by a very strong Nisus. And I remember, Dr. Lister, some where in the Phil. Trans. relates how he try'd to get in a very fine ting'd Spirit into the Lacteals of a live Dog, by cuting the small Guts, and injecting the Liquor, then sewing all up again: But he cou'd never get it done to his Satisfaction. And here it is to be observ'd, that people may be deceiv'd with Blue Tinctures; for this is the Natural Colour of these Lacteals when they are almost or altogether empty.

If it be objected, 1. That the Concoction of the Stomach and Intestines may fit this Morbifick matter, to be separated by the Lacteals. 2. That the Peristaltick Motion and the Valves of the Intestines may hinder the quick motion of the compounded Chylous matter. 3. That there are some Medicaments, as Turpentine, &c. which we know, by their effects, get into the Mass of the Blood, and yet are more viscid than our Morbifick matter. 4. That there is rereally as viscid matter separated in some other Glands, as the Bile and the Phlegm.

To these I answer,

1. As to the first; seeing triture is the only effect of the Stomach and Intestines, there is no advantage to be reap'd thence; for no beating nor g•ating will dissolve the union of this Morbifick matter. Besides where it is in any plenty, the effects of Concoction are very small, or none,

2. As to the Second; The Peritaltik motion being reciprocal, it adds as much (to the motion of the Chylous matter) in it's descent towards the Rectum, as it takes away, in its ascent towards the Stomach; and so cannot serve that end, the Plicae and circumvolutions of these Intestines (which we have consider'd) being only to be rely'd on, for this purpose. As to the Valv's, we know they all open toward the Rectum, and serve only to stop the ascent of the Faeces in the Peristaltick motion, and so cannot retard the motion of the Chylous matter.

3. As to the Third; We likewise know, that all these Medicaments are dissolv'd into a thin Liquor by heat (as Turpentine, Butter, &c.) Besides that only the most spritious and least viscid parts enter the Blood; which is not said of our Morbifick matter.

4. As to the last; There is a great difference betwixt a Liquor immediately after it is separated, and when it has Stagnated sometime in the Conservatory of the Gland; for then the Aqueous and more humid Parts evaporate; and by its stagnation it acquires an ineptitude to motion: And tho the Blood flows very easily in the Arterys and Veins; yet I defy any to cause extravasat Blood enter its Vessels again. But more particularly, we must consider the Liver to be a very large Vessel, and (if it were evolv'd) to make an Artery many Thousand times longer than that of the Canal of the small Intestines, or Testiculus Humanus either; and so it is no wonder it separate a viscid matter; the motion of the Blood there being very small: But still I assert it is not near so vicid as our Morbifick matter. As to the Phlegm, we know it is not naturally produc'd; and the Morbifick matter it self (against which we dispute) might be as well objected; for it is only the Stagnation, Corruption and Evaporation of the Humidity, which occasions both; the same might be said of the Purulent matter which passes by Ʋrine, but that we know it proceeds from an Ʋlcer in the Kidney or Neck of the Bladder, and is not discerned with the Ʋrine.

Having dwelt thus long on the Opinions of others, I come now to consider the proper remedies of Fevers which I reduce to, 1. Blood letting, 2. Vomiting, 3. Purging, And, 4. The Medicaments which encrease the less Sensible Evacuations; under which head I comprehend Sweating, Perspiration, and the like.

I do not here consider blistering and outward Applications; seeing (in my Opinion) they are only useful to remove the accidental effects, and not the cause of Fevers, without which they cannot be said to be truly cur'd.

1. As for Blood letting; The subject is so fully and learnedly treated by Bellini in his foremention'd Books together; that it were equally impossible as impudent to offer at any additions: And therefore for intire satisfaction on this head, I shall refer my Reader to these Books.

2. As to Vomiting; I shall comprehend all I have design'd to say about it in these particulars, 1. I shall show that Vomiting is partly produc'd by the vis stimulans Vomitorii: But, 2. That it is mostly occasion'd by the vis stimulans of the Morbifick matter excern'd from the Glands of the Stomach. 3. I shall prove that this Morbifick matter is not in the cavity of the Stomach (at least in such plenty as it is excern'd by a forc'd Vomit) before the ingestion of the said Vomit. 4. I shall give the whole destruction and connexion of this Operation; And, 5. Shall consider the advantages of the same in the cure of Fevers.

Before I come to handle these, it is necessary, I first explain what I here mean by a vis stimulans.

By a vis stimulans, I understand such a Quality in a Fluid, whereby the particles thereof are dispos'd to make a real division or a violent inflexion of the Nervous and Membranous Fibres of the Body, which occasions frequent and forceable reciprocations, successions and derivations of the Liquidum Nervorum into the Muscles and contractile Fibres of the Canals; whereby all the involuntary Muscles are brought into violent contractions, and the emissaries of the Glands are squeez'd.

Those who desire a fuller account of the nature and mechanical Operations of this vis stimulans, may see it, Pag. 165. and Seq. of Bellini's Book De Ʋrinis & Puls. & Prop. 52. of his last Book De Motu Cordis. I say then,

1. Vomiting is Partly produc'd by this vis stimulans Vomitorij; This is evident from these considerations. 1. Because sometimes we immediately Vomit upon the Ingestion of the Vomitory, before the Morbifick matter excern'd from the Glands of the Stomach could have time to concur. 2. We throw up very often the same we had taken in, with little or no mixture; which could not happen, if the Morbifick matter had concur'd to produce the fit. 3. Sound persons (in whose Stomachs there is little or none of this Morbifick matter) often Vomit upon a too plentiful ingestion of an (otherwise) inoffensive Liquor. The only reason of which must be that the Stomach not being able to derive into the Mass of the Blood the said Liquor, so fast as it is pour'd in, it must Sowr on the Stomach, and thereby acquire this vis stimulans, whereby it is thrown out: Or perhaps it may still have a vis stimulans, tho not (when it is in a small quantity) sufficient to bring the Stomach into that violent contraction which is necessary in Vomiting; But this small vis stimulans being Multiply'd by the too great quantity of the Liquor, may acquire sufficient force to produce the effect; as we see several things lose the quality to produce their visible Effects, when in small, which they had when in great. But, 2.

I say, Vomiting is mostly accasion'd by this vis stimulans of the Morbifick matter excern'd from the Glands of the Stomach; and that for these reasons, 1. The action of the vis stimulans Vomitorij being terminated at, or near the internal surface of the Stomach, after one or two plentiful fits of Vomiting, (there being produced thereby such a succussion and compression of the sides of the Stomach) these Particulae Stimulantes must necessarily be disentangled; and so there could be no more fits of Vomiting, which is contrary to experience. 2. We evidently see in Sea-Vomits, and in those produc'd by the Joltings of a Coach in some people, there is no vis Stimulans Vomitorij to which we can attribute this effect; and therefore it must necessarily be produc'd by the vellications of the Morbifick matter excern'd by this particular motion. The manner of which may be thus explain'd, every particular body has a determin'd degree of tension and a determin'd length. And if a like reciprocation of motion (by whatsomever cause) be produc'd in the ambient Medium, which would necessarily be produc'd by another Body (when mov'd) of the same degree of tension, and of length commensurable to the length of the first body, there must be of necessity a motion produc'd in that first body, especially if the motion of the Medium be violent, and the commensurable lengths be as the first number's of the ordinary Arithmetical Progression, 1. to 2. or 1. to 3. or 2. to 3, &c. This is evident in the unisone or concordant Strings of greater Musical Instruments: And the Reason is, because thereby the Oscillations of such Bodies become Commensurable. Now I suppose this particular Motion of Jolting Coaches and Ships, to be such, as would be produc'd by another Body having the just now mention'd Analogy to the Nerves of the Glands of the Stomach, whereby they are brought into motion, and consequently derive great Plenty of their Liquidum into the places, which makes such contractions as squeez these Glands of the matter, which produces these fits of Vomiting: Besides that the same cause may (upon other Fibres) produce the antecedent Sickness which we feel in Sea-Vomits. 3. By a Vomit of warm water (for example) there are often produced several fits of Vomiting; and yet we all know there is no vis Stimulans in it; So that all it can do, is, that by its warmth (which is a kind of a Fotus) it elicits the matter from the Glands of the Stomach, which occasions this Vomiting. I cou'd add a great deal more to confirm this proposition, but I think this sufficient. I say,

3ly. That the Morbifick matter (excern'd by Vomiting) is not existent in the Cavity of the Stomach, (at least in such Plenty at it is excern'd by a forc'd Vomite) before the administration thereof. 1, This is an evident Corollary from the former Prop. The Vomite does not Act (at least after the first one or two fits) by it's own vis ctimulans; There is (in Vomiting) produc'd a violent contraction of the Fibres of the Stomach, the Muscles of the Addomen and Diaphragm, which must be occasioned someway. There is nothing (in Vomiting) which can occasion this, but either the vis •timulans Vomitorii, or of the excern'd Morbifick matter; and since (as has been already proved) it can not be the former, it must of necessity be the latter: Wherefore if the Morbifick matter were already existent in the cavity of the Stomach, the Vomite were of little use after one or two Fits; which is contrary to experience. 2. If this Morbifick matter were already in the cavity of the Stomach, it is not possible but that one or two plentifull fits of Vomiting would eject all that is there; so that afterward there should none be thrown out however violent the consequent fits were, which is likewise contrary to experience. The force of the Muscular Fibres of the Stomach, The Muscles of the Abdomen and Diaphragm (which two last Monsieur Chirac, Professor of Medicine at Montpellier, by an easy experiment, has shewn to concur principally in Vomiting. vide, The Preface of Tournfort's Histoire des Plants qui Naissent aux environs de Paris) is at least equal to 260000 lib. weight; (the force, of the Muscles of the Abdomen and Diaphragm being more than that of 248000 libs. and of the Stomach, not inferior to that of 12000 pounds) which force if it be not sufficient to drive out all that is existent in the cavity of the Stomach (however Viscid the matter be) I leave every one to judge. 3. Supposing the Morbifick matter already in the cavity of the Stomach; It is Impossible to give an account of the different effects of different Vomits: For Example, why an Antimonial Vomit does excern this Morbifick matter more plentifully than Whey or warm Water. For if before the Ingestion of either, the Morbifick matter is already in the Stomach, then the only thing left for them to do, is, to excite the Act of Vomiting: But it is certain they may be both brought to be equal in that, i. e. they may be both brough to excite an equal unmber of fits of Vomiting; and that with equal violence (by taking their Quantitys in a reciprocal proportion to their Vomitive Faculties) And yet their effects be very different, otherwise I omit (for avoiding tendiousness) the other arguments I can aduce to confirm this proposition.

4ly. The whole deduction and Connection of this operation is thus: the Particles of the Vomitory by their Incuncation into the Orific•s of the Emisaries of the Glands, adjacent to the surface of the Stomach, do dilate the same (which by some extrinsick cause) had been contracted and after the same manner do dissolve (at least in some degree) the Cohesion of the stagnant Morbifick matter, and render it more Fluid; and consequently, its resistance less: Now the natural and constant action of the Glands being Secretion; and the Impedimentum (by the dilatation of the Orifice and attenuation of the Fluid) being totally taken away, or (at least) made less than the natural Momentum of the Glands; The matter must necessarly flow into the Cavity of the Stomach, till it be accumulated in such a Quantity (which not being to be done in an instant, must require some time) as is sufficient (by the united loathsomeness and the vis stimulans of it and the Vomitory) to vellicate and force the Fibres of the Stomach, Abdomen and Diaphragm (by the communication of the Nerves of the first with the two last) into a violent contraction, and thereby throw all out by the Osophagus, which brings all to quiet again, Till there be a new, a sufficient quantity exerned from these Glands to reproduce the foresaid Contraction: And thus there happens a fit of Vomiting and Quiet alternately, till either all the Morbifick matter be thrown out, or the force of the Vomit so diluted, that it's no longer able to elicit the Morbifick matter from the Glands. Besides these Primary effects of Vomiting, there are two others, which ought not (tho less principal) to be omitted. The first is, that in a strong Vomit, or in one which requires some considerable time before it operate, there often passes some part thereof from the Stomach into the Intestines, and occasions a gentle Purge, by dissolving the Faeces, and vellicating the Fibres of the Intestines, as shall be more particularly shown when we speak of Purging. However the effects of this, Purge very seldom, or never go beyond the Primae Viae, For all gentle Purges (of which this is one) are confined within these. The second is, that the strong contraction in so many Muscles and Muscular Canals, which are at Work in Vomiting, and the violent concussion which is produc'd over the whole Body, by a power (as has been said) which is not inferiour to that of two Hundred and Sixty Thousand weight, may and often does, take away the Obstructions in many other Canals, than those which are more immediately concerned about the Stomach and Osophagus, as we evidently see by that vast Sweat which always breaks out after plentiful fits of Vomiting. From these I deduce,

5thly. The Advantages of Vomiting in the Cure of Fevers; which are, 1. The taking away the Obstructions of the Glands of the Stomach and (sometimes of the Intestines, which is the principal use of Vomiting; and how great a step this is toward the Cure of Fevers, every one will see who considers, that in Fevers occasion'd by Intemperance, the Stomach is the Scene where this great Mischief is both contriv'd, and put into Execution; the Obstruction of the Glands thereof, being the first and principal Cause of these Fevers; And in Fevers occasion'd by Cold, the Stomach and Intestines being most Expos'd, and least Defended from the Cold Air, receives its first and strongest Impressions; which two (as formerly was said) have the most considerable share in the cause of our Continual Fevers: And therefore it is, that Vomiting (being timeously and plentifully us'd) very often prevents such Fevers. 2. Another Advantage of Vomiting is, That by the strong Contraction of the Muscles and Muscular Canals and the violent Concussions of the whole Body thereby produced, the Obstructions of many other Glands are remov'd, as has been just now shown.) So that this with the former (removing so considerable a part of the Cause, enables Nature to perform the rest very easily. 3. A Third Convenience (if not Advantage) of Vomiting, is, That it is less dangerous than many of the Medicaments that are taken inwardly; The effects of this is confin'd to the Primae viae; (by which I always mean that winding Canal, which is continued from the Mouth to the Sphincter ani,) and is consequently less dangerous than those which run the Circle of the Blood; For it is not to be doubted, that all Alterative Medicines have more or less danger in them (from the effect of their Stimulations upon the Nerves, their Fermentations with the Blood, their Separating, or Promoting the Natural Cohesions of the Liquors of the Body, and their many other unknown Productions.) That which goes the least way, must therefore have the least danger: Now since it is certain, that Vomiting does not go out of the Stomach and Intestines (where the Canals are strong and wide, and the Fluids are viscid and gross) there must of necessity be less danger in it, than in these which enter into narrower and weaker Canals fill'd with more Fluid and finer Liquors. It is true indeed, there is some hazard from the bursting of the Capillary Vessels of the internal Surfaces, by the violent Concussions of the Body, occasioned by Vomiting; but this is easily prevented by Blood-letting, which ought always to preceed the plentiful use of vomitories in all Diseases. Besides, sometimes the violence of Vomit, is too great for the strength of the Patient; but this is rather the fault of the Physician than the Physick: For the Strength, and (consequently the violence of Vomits, as of all other Medicines) ought to be adjusted by this Proportion, Viz. They ought to be in a compounded Proportion of the strength of the Patient, and the danger of the Continuance of the Disease. If this were observed, none cou'd ever Err in the Administration of Medicines.

III. Come we now to that which we call'd the Third proper Remedy of Fevers, to wit, Purging; In explaining of which, I shall, 1. Shew that Vomitive and Purgative Medicines differ only in degrees of the same Quality. 2. I shall give a short account of the several steps, and of the manner of this Operation. And, 3. Consider its use in the Cure of Fevers. I say then,

1. That Vomitive and Purgative Medicines, differ only in the degrees of the same Quality, i. e. Purgative Medicines, by encreasing their force vastly, and confining it to a lesser Quantity, either of a Fluid or solid Body, become Vomitive, and Vomitive Medicines (if diluted) become Purgative. This will be evident from these Considerations. 1. We find by Experience, a strong Purge never misses (if either it be very strong, or the Patient not very strong) to Vomit, and the weaker part of a Vomit, which escapes into the Intestines, does frequently Purge us. 2. The same Medicines (for example, Vinum Emeticum,) taken by the Mouth, will provoke Vomiting, which giv'n by way of Glister, will Purge: The same obtains in all strong Emeticks. In short, all strong Medicines of either kind constantly produce both these Effects. The reason of all which is this; If the Medicament of either kind be so strong as immediately to vellicate and stimulate the Fibres of the Stomach, to dilate the Orifice, and attenuate the matter contain'd in the Glands thereof, it produces Vomiting; if it act but gently, so as only to assist the Natural Motion of Digestion, it goes by the Intestines, and dissolves the Cohesion of the Faeces, and finding there more sensible Fibres, is able to bring them into violent Motions, which produce Purging, as shall be just now show'n. 3. It is impossible in any other Theory, to account how these two different Medicines shou'd upon the same Parts produce different Effects; For both these Medicines are taken by the Mouth, go down the Osophagus, and enter into the Stomach either in the form of a Liquid, or are there by it reduc'd into a Liquid; and consequently are brought in to contact with, and Operate on the same Fibres, Glands and Membranes; and yet produce (by their assistance) two different effects. It is simply impossible to explain the manner of this, without saying the one acts more powerfully and forceably, and makes more violent Contractions, and consequently is thrown up the most patent way; the other more gently and softly, and has thereby time to seek out the less obvious passages.

2dly: The account of the several steps, and of the manner of this Operation, is thus; Purgative Medicines, being receiv'd into the Mouth, and admitted into the Stomach, their particles vellicate and stimulate the Fibres thereof, and thereby encrease the digestive faculties, i. e. bring the Muscular Fibres of the stomach, the Muscles of the Abdomen and Diaphragm into more frequent contractions than ordinary, till they are admited into the Intestines, the Fibres and Glands of which being more sensible than those of the Stomach (whose parts by the frequent rough Contacts; of one against another, and of the gross Bodies which are often thrown into it, are as it were dead'ned) they easily move and bring into frequent and forceable contractions, whereby these Glands are squeez'd of a Fluid which lubricates the Passages; and mixing with the feculent matter of the Intestines (which is rendered Fluid by the same active and Stimulating quality of the Purgative medicine) renders it yet more Fluid, by which (and by the more than ordinary contractions of the Intestines) it passes more plentifully and easily into the Rectum, and is thence ejected. This is the use of the more gentle Purges which only cleanse the Intestines. But those of more force (besides all these) do (as to the greater and more spirituous part) enter into the Mass of the Blood by the Lacteals, and mixing therewith produce many unnatural fermentations therein, separating or promoting the natural Cohesions of the Liquors of the Body, and accasioning many other unknown effects, as has been formerly said: And likewise there, vellicating the spiral Fibres of the Arteries and Veins, bring these into more forceable contractions, and thereby promote the Circulation of the Blood and make it run with greater Velocity and force; and by this means in a short time wash away any obstructions that either happen to be in the more direct Arteries, or the more complicated ones which constitute the Glands, encrease the insensible perspiration, and purifie the Blood of all the grosser and more noxious parts, by the Ductus Cholodochus and Pancreaticus which void themselves into the Intestines. All these effects of the more powerful Purgatives are Visible; for sometime after one has taken such a strong Purge, we find the Pulse mightily encreas'd, the Perspiration augmented, the Spirits, or Liquidum Nervorum spent, spent, the visible Excretions by Siege and Urine much greater, and the Body weak'ned; especially after a few days of such a course. Whereby it is evident these Medicines must operate after the manner ••w explained. From hence it is clear,

3dly. That the advantages of Purging in the cure of Fevers are very great, upon these two considerations: 1. If the Purge be more gentle so that it only serve to cleanse the Intestines, it partly takes away the obstruction of the Glands of the Stomach, and totally that of the Glands of the Intestines, which is a considerable step towards the cure. But, 2. If the Purge be more violent, so that it enter in any plenty into the Mass of the Blood, it conduces so much toward the removal of the obstructions of most of the other Glands, that nature is able to perform the rest very easily her self. But alas! this last case has so much danger, and so many inconveniencies in it, as render it as unsafe, as otherwise (if these could be remov'd) it would be useful. Bellini in his Book De Ʋrinis & Pulsibus, page 222. has demonstrated that in violent Purges there is a greater danger by far than in Blood-letting. His words are, Quia vero quicquid est suspicionis in missione Sanguinis ad solum fermentationem non naturalem, quae possibilis per ipsam est in reliquo Sanguine, redigitur, & hoc uno de nomine periculo non vacat; si igitur hujus mali suspicione careret purgatio, illa potius adhibenda, quam venae sectio; cum purgatio ejus loco caetroquin esse possit: sed res e converso se habet, suspicio enim ejus mali a missione Sanguinis est suspicio rei possibilis non tamen necessario prevenientis, aut necessario conjunctae, cum qualibet missione Sanguinis; in purgatione autem necessarium semper est Sanguinem solvi a naturalibus Cohesionibus, seu recedere & dimoveri a sua compositione; In Purgatione igitur periculum erit certum, in venae sectione dubium: hoc est, erit Purgatio venae sectione periculosior, &c. And therehe goes on to shew how muchmore dangerous Purging is than Blood-letting: From this and a great deal more he has there adduc'd, it is evident, 1. That violent Purges have a great deal of real danger in them absolutely, without respect to other remedies; and indeed these unatural Fermentations and changes of the Cohesion of the Fluids instead of promoting the cure, often encreases the cause of Fevers, to wit the obstruction of the Arteries which constitute the Glands. 2. That violent Purges are respectively much more dangerous than Blood-letting, wherefore this last is a more safe, and consequently a more useful expedient in the cure of Fevers than the former. And I say, 3. That violent Purges are a much more dangerous remedy in Fevers, than Vomitings are; For Vomits extend no further than the Primae Viae, where the Canals are strong and wide, the Fluid viscid and Gross, But violent Purges reach all the slender Vessels and Noble Liquors of the Body, where the danger of any Considerable alteration is extreamly great. Wherefore upon this account, I say, that the danger of Violent Purges is to that of Vomiting, as the length of the Canals of the whole Circuit of the Blood, is to the length of the Canals of the Primae Viae. And how much longer the first is than the latter, I leave the Reader to consider. Besides all these, there are so many other known and evident dangers in violent Purges, that the only part of Purging which is safe (in curing Fevers) is Glistering, 〈◊〉 the Lotiones Alvi, or rather 〈◊〉 either of these, only that gentle Purge which is the concomitant of every plentiful Vomiting.

IV. We are come now to the last proper Remedy of Fevers, which was the Medicaments which encrease the less sensible evacuations. But all that can be pertinently said on this head; is so learnedly and accurately already handled in a Treatise entituled, Archibaldi Pucarnij Dissertatio de Curatione febrium quae per Evacuationes instituitur, that thither I shall refer the Reader, only adding the reason why such Medicaments Administred in the begining of Fevers, do rather encrease than cure them, which is this: In an Obstruction of the Glands, the Blood in the Complicated Arteries which constitutes the same, stagnates up to the next Branching thereof, nearest the Heart, and thereby a considerable length thereof becomes obstructed and unpassable; the only way this obstruction can be remov'd is by the force of the Blood, which in every Pulse or contraction of the heart, washes off a particle of the same till the whole be dig'd away; as shall be shown. Now the Arteries which constitute the Glands, whereby the insensible evacuations are naturally secern'd, being in the begining of the Fever so much obstructed; It is simply impossible for such Medicaments to carry these obstructions off as they are just now; they must rather force through the superficial Arteries, and those few other Glands that are (perhaps) left passable, the natural humidity only, i. e. the thinest Parts of the Blood, and consequently make it more viscid, and thereby the obstruction more firm, i. e. will encrease the Fever; whereas, when a great deal of these obstructions in the Arteries are wash'd away by the force of the Blood, i. e. in or near the decline of these Fevers, such Medi¦caments will be able to force the small remainder of these obstructions either through the Orifice of the Gland, or into the continued Vein, till by frequent circulations it be either lost, or thrown out of the Body.

From all that has hitherto been said about the cure of these Fevers, It is evident.

COROLLARIA.

1.THAT the first thing incumbent upon a Physician, in the case of these Fevers, is to let a considerable quantity of Blood, both in order to remove the cause of these Fevers, and to prevent the inconveniencies of the subsequent Vomiting. Bellini in Prop. 5. and 6. De Febribus has demonstrated that Vena in omni morbo est secanda, in quo minuenda quantitas, aut augenda velocitas, aut refriger andum aut humectandum, aut aliquid adhoerens vasis dimovendum aut abripiendum. Than which there cou'd be nothing more pat to our Theory.

2. The Second step in the Cure of these Fevers, is Vomiting; for it at least removes the Obstructions of the Stomach and Intestines, and goes a great length to take away the Obstructions of the most of the other Glands likewise This especially obtains in Fevers occasion'd by Intemperance or Cold: As is evident from what we have said about Vomiting; But as for Purging in Fevers, there is very little more safe than what is the necessary Concomitant of all such Vomitings.

3. The last, but most Universal, and surest step, is the encreasing the less Sensible Evacuations: But this must be used only in the decline of these Fevers, as has been just now shown.

I have in this place only determined the Order, and the several Degrees of the Efficacy of these Remedies (in the Cure of Fevers) with respect to one another: Their Kinds and Quantities being to be adjusted by a former Analogy I have given, when I was speaking about the Advantages of Vomiting.

But here it may be very fairly ask'd why (since I make the Obstructions of the Artery and Nerve which constitute the Glands, the principal cause of Fevers) do not I allow Mercurial Medicines (which all grant to be one of the most proper, and perhaps Specifick remedies of obstructions) to be one of the steps of the cure of these Fevers.

Before I answer this question I shall, 1. Explain the nature of Mercury. 2. I shall shew the manner of the Operation of these Medicines; and, 3. The advantages and usefulness of them.

I. As to the first I Suppose.

1. That pure Mercury, or Quicksilver, consists of parts (I mean those of the first composition, by which I understand an aggregate of the Smallest and last constituent Particles of any Body, and an aggregate of these aggregates I call of the Second composition; and so on) exceedingly small equal, and perfectly Sepherical.

This has been suppos'd by all who have written any thing tolerable about the Nature of this Mineral; it is true indeed, some have suppos'd it so, because they saw that dividing Mercury upon a plain (even by the assistance of a Microscope) still the upper part retain'd its Sphericity, which they could not so easily observe in other Fluids: But the true Reason of this is, The great Gravity of the Mercury, in respect of other Fluids, and the uniform pressure of the Medium. For all Fluids will retain their Sphericity till their Quantity be so diminish'd (either by their being another Heterogeneous specifically lighter Body included in them, or by their Gravity decreasing at a greater rate than their Surfaces) that they are of equal Gravity with unequal Portion of the Medium they are in, and then they will receive any Figure the Motion of the Medium can imprint on them. However the divisions of Mercury must be very small before it can be reduc'd to this State; but that it can at last be brought to it, is evident from the mixing and pounding of Quicksilver among common water, in which we know a part of the Quick-silver is lost, by the Diminution of its weight, and the discolouring and effects of this Water.

But the true Reason why the former Supposition is to be made, is, because from it some of the Phenomena of Mercury may be accounted for.

For, from thence it is evident, why Mercury (tho' the heaviest known Fluid) rises with fewer degrees of Heat in an Alembick, than any other. 1. It's parts (of the first Composition) being exceedingly small, i. e. smaller than such parts of any other Fluid, it must rise sooner than they; because the Gravity of its Particles has a lesser Proportion to their Surfaces, than the Gravity of the Particles of any other Fluid has to their Surfaces; for the Gravities of Bodies decrease in a Triplicate Proportion, whereas their Surfaces decrease only in a Duplicate one. Thus supposing (for Example) the Diameter of a Particle of Mercury (of the first Composition) to be to the Diameter of a Particle of Water (of the same Composition.) As 2 to 300; (and we may justly suppose the Odds infinitely greater,) their Surfaces will be as 4 to 90000. And their Solidities, i. e. their Gravities, as 8 to 27000000. This upon Supposition their Specifick Gravities were equal; but supposing (at the largest) the Specifick Gravity of Mercury to that of Water, as 15 to 1. The real Gravities of such Particles will be to one another, as 120 to 27000000: Whence it is evident, that not only the ratio of 8 to 4 or 2 to 1. is much less than that of 27000000 to 90000 or 300 to 1. And therefore upon such Supposition it will follow, That the Gravities of such Particles of Mercury, wou'd be much less than that of such Particles of Water: And that the Surfaces of these Particles of Mercury, wou'd be much larger, in respect of their Gravities, than that of the like Particles of Water, in respect of their Gravities; and consequently the Mercury wou'd rise in the Alembick with much Fewer degrees of Heat, than the Water upon this account. But, 2. The Particles of Mercury are perfectly Spherical and Equal; (for all Homogeneous Bodies must consist of Particles Similes & aequales in the Euclidean Sense, Vide Def. 1. 6. & 9. 11. Euclid.) and consequently can only touch in points, and thereby their Sublimation will become more easie. A Sphere can be touch'd but by 12 other equal Spheres, and that too, but in so many Points; and if we suppose the Superficial Particles of the Mercury to be first rais'd in the Alembick, they can be touch'd only by 9 other. Now the Force and Value of such a contact as this of 9 Points, is less (Caeteris paribus,) than that of other solid Bodies generated by the Circumrotation of what ever Figure, Regular, or Irregular, Right-lin'd, or Curvelin'd: For, The Contacts of Circles is the Measure of the Contacts, of all other Figures whatsoever; and tho in some Curves their Contacts in some Points, may be less than that of Circles, (vide Scholium Lem. 11. Princip. Phil. Mathem. Newtoni.) yet in all their other Points, they will be Proportionally greater, and consequently the value of the whole Contacts greater than that of Circles; wherefore it is evident, that Spherical Bodies will be more easily separated than any other, and consequently will rise in the Alembick with fewer degrees of Heat than any other. I Suppose,

2dly. That the only Effect of the Sublimations, and other Preparations of Mercury, is the dividing it into these parts of the first CompositioN, which are Spherical, Per suppos. 1. Or into parts of a more complicated Composition, which (by reason of the vast Gravity of Mercury, in respect of other Fluids, and the uniform pressure of the Medium) may be still Spherical; For if the Mercury be pure, and no Heterogeneous lighter Body be mix'd with it, it will still retain its Sphericity till the ratio of the Surface of a Particle of Mercury to its Gravity, be to the ratio of the Surface of a Particle of Air to its Gravity, as is the Specifick Gravity of Mercury to the Specifick Gravity of the Air, i. e. (putting the Specifick Gravity of Mercury to that of Air, as m to n; and the Diameter of a Particle of Mercury x, and that of a Particle of Air a.) till m∶u∷1/x∶1/a Then x will be equal to na/m that is, (supposing a equal to Unity as the Standard, m to n as 10800 to 1 proxime, as all know) the Diameter of a Particle of Mercury must be 10800 times less than that of a Particle of Air, or the Particles of Mercury themselves, 1259712000000 times less than these of Air, before they lose their Sphericity. Now besides these divisions into Spherical Particles, the Saline Bodies which are mix'd with the Mercury in these Preparations keep these asunder and disjoin'd, like so many congeal'd little Bullets separated by the Fixation of some Liquor. This is (as I suppose) the whole effect of these Preparations; as is evident from what Mr. Boyle and all other Chymists have found; to wit, That from all the Transmutations, and Preparations of Mercury they cou'd elicite the same uniform heavy Fluid; which cou'd never happen if there were any other (besides the now mention'd) effect produc'd by these Preparations: For by what means soever you dissolve this congeal'd Seperation, the greater Gravity of Mercury brings its Particles into their former Union, and thereby reduces them into the same Fluid Quick-silver. Besides these two Suppositions, it is to be observ'd,

1. That the chief Ingredients in Mercurial Preparations are (besides it self) common and Armoniack Salts, and their Spirits, the Spirit and Oyl of Niter, Vitriol and its Spirit, and the like (which afterward we shall call by the General Name of Saline Bodies,) All which (we know) are endued with a vast power to vellicate and stimulate the more sensible parts of Animal Bodies, and (consequently) to produce Vomitings and Purging (of themselves) according to their Quantity, and the degrees of their Natural force.

2. That the only effect of repeated Sublimations in these Preparations, is, the division of the Mercury into smaller Particles, and the freeing of these from the Grosser and more Noxious parts of these Saline Bodies; for Mercury sublimating more quickly and easily than these other Saline Bodies, must in repeated Sublimations have a greater proportion to the Saline Mixture than in the first Sublimations, and consequently the subsequent Sublimations must have less of those Saline Bodies than the Antecedent, whereby the Preparation will become sweeter and less vellicating. This is evident from the aquila alba & panacea Mercurialis, which are all much heavier (specially) than any other Preparations of Mercury,

These things premis'd, I come to explain,

II. The manner of the Operation of Mercurial Medicines; In performing which, I distinguish two Cases. 1. Either the Medicine is taken inwardly. Or, 2. It is apply'd outwardly; under which head I comprehend both Mercurial Inunctions and Plasterings. As to the 1. After the Medicine is taken by the Mouth, it desends into the Stomach, and there the Saline parts of the Composition vellicat the Fibres thereof, which occasion those Gripes are felt upon the taking these Medicines: And if the Salin Particles have a considerable share in the Composition, they so powerfully stimulat the Fibres of the Stomach, as to bring it into these Contractions which produce Vomiting, as has been formerly explain'd: The Mercury it self, with some of the remainder of the Saline Particles sliping into the Intestines, do likewise vellicat these, and occasion a Gentle Purge; which Effect, tho' it be constant (in the first days after taking these Medicines) yet it is never so violent as that of other Purgatives; because most of it's force is spent in the stomach. Now that both the Vomiting and Purging produc'd by these Medicines, are owing to the saline parts of the composition, is evident from the nature of Mercury, and the effect produc'd in it by the Chymical preparations thereof just now explain'd: For Mercury consisting of spherical Particles, and by such preparations being only divided into these, of themselves (as being spherical) these particles cou'd never occasion the stimulatitions, which (as has been formerly shown) are necessary to produce these effects. The only thing they can contribute towards them is, that by their excessive gravity and smallness they are capable to dissolve the Cohesion of the more viscuous Fluids of the stomach and Intestines and consequently make them flow more easily, when the Muscular Fibres of these parts are otherwise brought into contractions. Besides, we see that the forementioned effects, are mostly produc'd by those compositions in which most of these Saline Bodies enter. As in the corrosive Sublimate, the White and Yellow Precipitate: But in the others which pass many Sublimations, (as the Sweet Sublimate, and the Panacea Mercurialis) we judge of their goodness as they produce least of these effects. I ascribe the Sweating produc'd by a dose of some of these compositions, partly to the violence of the Vomitting, and partly to the Saline Particles which enter the composition; and that small salivation, to the Imediate action of these Saline Bodies upon the Salivary Glands, and not to the Mercury it self. All these will be evident to any who have seen the sudden effects of these Medicines, which have not had sufficient time, neither to enter nor circulate with the Blood, so as to be able to produce the mentioned Sweating or salivation after the ordinary manner. Thus I have endeavoured to explain the effects of these Medicines while they are in the Primae Viae. I shall now show the manner of their Operation in producing a Flux de Bouche, that thereby the lesser effects of this kind may be understood.

The Mercury being free'd (by the action of the stomach and the heat of the Liquors contain'd in the same and in the Intestines) of most of the saline part of the composition, enters the Blood by the Lacteals, and is with it carried about through the Canals where either it, or any Liquor (of the Body) generated by it, Flows, (the small remainder of these Saline Particles, which adheres to the Mercury after the action of the Stomach and Intestines, assisting the propagation of the motion, by the velicating the sides of the Canals) And having the same Celerity, but a much greater weight, it has consequently a greater force, and produces a stronger Ictus, and thereby (when once any considerable quantity thereof has enter'd the Blood) it (by it's great force and the smallness of its particles) disolves the unatural Cohesions of all the Liquors, renders them more Fluid, and active, and likewise digs out all the Obstructions of the impassable Canals like so many little Bullets shot against a mud Wall, every little Bullet breaks down a part till the whole be levelled; and this it is the more able to perform, both because it is exceeding weighty, and makes therefore a greater and more forceable Ictus, and because it's particles are exceeding small, and are therefore to be consider'd as so many exceeding sharp Wedges or Cunei. Besides by the smallness of it's Particles it is able to enter into these slender Canals in which the Blood cannot freely pass, and thereby to scour all the Passages be they never so small. And that there are Canals through which the Globules of the Blood cannot freely pass, we are convinc'd from Microscopial Experiments. Thus all the Liquors of the Body being attenuated, and consequently their celerity and force rendered greater, and all the Canals scour'd, and render'd passable, the whole Glands of the Body are set a work, and throw out the more noxious and less Fluid parts of their Liquors (by reason the particles of the Mercury either dissolve, or carry before them all the gross particles which resist them) and thereby the Perspiration, Urine, Salivation, are encreas'd, the quantity of the Fluids lessen'd, and the whole Body emaciated, till there be nothing left but pure and useful Liquors, and clear and passable Canals. Those who can only be convinc'd by occular Demonstration may see a kind thereof in Phil. Trans. for Jan. 1700. where Leuvenhoeck from Microscopial Experiments on Tad-poles, confirms the main of this Doctrine, as to the manner of the taking away Obstructions.

But there is another Effect of Mercurial Medicines, which is noways to be forgotten; for besides these mention'd Effects, it distroys that corrosive Faculty of the Liquors which bursts the superficial Vessels, and produces those constant pains, Scabs, Ulcers, and the like, which we feel; For, supposing an Obstruction in any Vessel (either by the corrosiveness or Viscidity of the Liquor, or from some extrinsick cause) the Liquor Stagnates and Coagulates there, and by the force of the fluent part of that Liquor, and by the Corrosiveness of the stagnated part, the Vessels are Miserably distended, and their parts dilacerated, which occasions constant pain in that part; or they burst, and the Liquor putrifying, occasions a Botch, Scab, or Ulcer, more or less Dangerous and painful, as the corrosiveness of the stangnated and putrifying Fluid is greater or lesser. Now this corrosive Faculty must proceed from the pointedness of the particles (perhaps these particles may consist of four equilateral Triangled plains, for such have the greatest equal degree of acuteness on all their points which seems necessary to make them equable in their Actions, and Homogeneous in their Natures) of the stagnated Fluid. Now the Mercury will not only remove the Obstruction, and make the Vessel passable by its weight, but likewise by the same will break off, and plain the points and Angles of these Particles, and so render them Harmless and innocent; for Sublata causa, &c.

But here it may be objected, that the grand effect (as most People believe) of Mercurial Medicines is Salivation, and that really the Salivary Glands secern more of their Fluid proportionally than any other Glands of the Body, which is contrary to the 5. Prop. about Secretion. To this I Answer,

1. That the principal effect of Mercury, is the attenuating the Fluids, the clearing the Canals, and the destroying the Corrosiveness of the Obstructions, and that salivation has no more title to be the principal effect of Mercury, than insensible perspiration. For all the Glands (notwithstanding the Objection) secret their respective Liquors in the proportion mentioned in prop. 5. about Secretion. 2. It is evident that salivation is not the main effect of Mercury, from this, That many persons are cur'd of very dangerous Poxes, Ulcers and Rheumrtisms without ever Salivating, at least at the ordinary rate of Salivation. But 3. The reason why we seem to secern more by the salivary Glands proportionally than by any or most others, are these, 1. The salivary Glands are more in number than any of those which separate visible Fluids; and consequently it is but reasonable they shou'd secern more than any other. It is true the Glands of insensible perspiration are more in number than those, and it is not to be doubted but they secern more likewise; and it will be found so when ever the thing is examined after Sanctorius's method; but that secretion not being visible, makes the matter doubted. 2. The Canals which constitute the Glands of salivation are evidently wider than these of others, as is clear from their spungy and soft Contexture, and so it is very accountable from the mentioned Prop. why they secern more plentifully. 3. The Fluid lecern'd in the Salivary Glands is Ropy and Viscid, and one part draws forward another, which does not happen in most other Glands, and upon this account it is no wonder that those secern more than these. 4. The Salivary Glands in some People, have not so good a Contexture, and so obvious a course as in others: And this is the Reason why some Salivat little or none, and others too much. But 5. The true account of the Matter is this, The Saliva being a tough ropy Substance, cannot be thrust out so fast as the Mercury carries it forward, especially seeing it seperates only the most Glutinous parts of this Saliva, whence all the Salivary Glands begin to swell untill there be such a quantity accumulated, as together with the force of the Mercury, and of the succeeding Fluid is able to burst the Orifices of the Glands: And it is observable, the Salivation continues only so long as any of the Glands are found swell'd. Whence it is evident that this plentiful Salivation depends upon this, That the Fluid is as it were laid up in store to be deriv'd more plentifully afterwards, whereas in the other Glands, the Fluid being thiner, is secern'das fast as it is driv'n forward: And hence it comes to pass, that we think the Saliva secern'd, is much greater in Quantity than what is deriv'd from the other Glands. If we take in all these Considerations together, they will account for the plentiful Salivation by Mercury.

2. As to the second Case: In Mercurial Inunctions the viscid Matter, in which the Quick-silver is wrought and pounded, serves only to keep the small Particles thereof separated and asunder, and to apply them to the Skin, till by frequent rough Frictions the smallest Particles of the Mercury are forced through the sides of the Cuticular Arteries into the Blood, and when once they are got thither they are in the Estate just now Mention'd, and operate after the manner already explain'd. And indeed this were the shortest and easiest course of raising a Flux de Bouche, if Mercury cou'd be adjusted to the Strength and Constition of the Patient, (for the Quantity of Mercury, which will kill one, will not produce the design'd effect of Salivation in another) by this Method, as exactly as by Administring it gradually in Doses, by the Mouth. But it cannot be done so, and therefore the latter course is the more safe.

Mercurial Plaisters apply'd outwardly to heal Scabs; or inveterate Ulcers, operate thus; The Corosive saline mixture, if there by any part thereof in the Composition, eats away and corrodes the putrid Matter, which sears up the Mouths of the Vessels; so that the Mercurial Particles get easily into them, where they both clear the Vessel of the Obstructions, and destroy the pointedness of the Particles of the Fluid, which two things did concur to make the Ulcer sore. If there be no Saline Body in the Application, then the Mercury must be forc'd in by Friction, into the Mass of the Blood, to produce the design'd effect.

Thus from a few easie and evident Postulates, I have giv'n an intelligible account of the Manner of the Operation, and of the Effects of Mercurial Medicines, when the Mercury enters in any Quantity into the mass of the Blood, and from thence it will be easily understood, that when the quantity is less, the Effects will be proportionally lesser: Sore that it will be needless to explain all the several degrees thereof by detail. But seeing it is evident from Leuvenhoeck's Observations in the last mention'd Phil. Trans. That the force of the Blood is able to wash away some Obstructions: let us take a gross estimat of the Proportion of the Efficacy of the Blood assisted by Mercury, to the Efficacy of the Blood of it self and unassisted to take away Obstructions. First, Then we must consider, if instead of the ordinary Liquors there pass'd nothing but Mercury in the Canals of the Body, the weight of Blood being to that of Mercury, as 1032 to 14593, or as 1 to 13 at least, and their Velocities being the same, Mercury wou'd at least be 13 times more able to remove the Obstruction than the Blood of self: But it is certain (if the Obstruction renders the Canal impassible,) there can no Particle of the Mercury get away; and (when there is any quantity thereof got into the Blood) there are still some new Particles thereof coming up, so that after some time (they having a greater Momentum than the Globules of the Blood, and thereby getting through it up to the Obstruction) we may consider there will be little or nothing save Mercurial Particles at, or near the Obstruction, driven against it, by the whole force of the Blood; So, that as to the Obstruction it self, it is very near the same, as if the whole Canals run Mercury. However, let us take the Proportion only as 1 to 10, so that upon this account the Blood assisted by any considerable quantity of Mercury, will be 10 times more able to remove the Obstruction than the Blood unassisted.

2dly. Let us consider, the Globules of the Blood are Elastick (for they often lose their Figure in strait Canals, and recover it again, as Leuvenhoeck has shown, which is the Definition of Elasticity) and those of Mercury are not, or very little so: And consequently upon this account, the Efficacy of the Globules of Blood will be hugely diminish'd, Let us suppose it looses ¼ of its Efficacy (which is a liberal allowance) and then the Proportion will be ¾ to 10, or 3 to 40.

3dly. Let us observe, That the Globules of the Blood, and Mercury driven against the Obstruction, and at every Pulse digging away a part of the same, may be considered as Cunei, now caeteris paribus, the Force or Efficacy of Cunei is reciprocally proportional to the Angles, their Edges make. But in spheres the lesser or greater degree of Curvity, is to be consider'd as these Angles, when these spheres are consider'd as Cunei: And the degrees of Curvity in spheres (as in Circles) are reciprocally as their Radii. Supposing then the Diameter or Radius of a Particle of Mercury is to that of a Globule of Blood, as, 1 to 100 (and there can be Reasons given, some of which I have formerly hinted, why the Odds may be suppos'd much greater) then the force of the Mercury, and the Blood, to that of the Blood unassisted, to remove Obstructions, will be as 4000 to 3. Lastly, let us consider, that by the force of the Mercury, the Liquors of the Body are exceedingly attenuated and render'd more moveable, and are thereby capacitated to receive a stronger Impression, so that they both move more quickly and with greater force, as is evident from the Pulse of those who are under a Flux de Bouche whose Pulse is little less frequent and strong, than the Pulse of those in a Fever. Let us suppose the Proportion, both of the frequency of their Pulse, and of its strength to that of an ordinary one, as 3 to 2, (and this is certainly much less than the truth.) Then it will be as 3 to 2 upon the account of its greater force, and again as 3 to 2 upon the account of its greater frequency, that is as 9 to 4. So that now upon this last, and all the former accounts, the proportion of the Efficacy of the Blood assisted by any considerable quantity of Mercury, to that of the Blood unassisted, to remove an Obstruction, will be as 36000 to 12 or as 3000 to 1. So that the first will be 3000 times more effectual for that end than the latter. But if any shou'd still think we have made too liberal Allowances for the Mercury, let us rebate the Proportion one third part; yet still the Blood assisted by any considerable quantity of Mercury will be able to do as much toward the removal of an Obstruction in one day, as the Blood unassisted in three years almost.

Besides, there are a great many cases in which the Blood unassisted, is so far from being able to remove the Obstruction, that it will continually encrease the same: For if the Obstruction proceed from a Depravation of the Liquors of the Body, as in Rheumatisms, or if some corroding matter, be forc'd into the Liquors, so as to be able to vitiate the same, as in Poxes, Pests, and Poisons, it is demonstrable, that (without some external assistance, either by Diet or Medicines) the Malady, instead of mending by length of time, will encrease. But if the Obstruction proceed from some external injury, as in Bruises, Wounds, Colds, and (perhaps all continual) Fevers, the Liquors (still persisting in their Natural and Wholesome Estate,) may do much to drive away the same by length of time; but still the sooner, and more safely if they be assisted by convenient Medicines. I come to,

III. The Advantage and Usefulness of Mercurial Medicines.

And, 1. They are useful for destroying the Viscidity and Thickness, the Corrosiveness and Pointedness, of the Particles of the whole Liquors of the Body, rendring them Fluid and moveable, Innocent and Harmless, if before they were otherwise.

2. They are evidently useful for removing all Obstructions, Ulcers, Scabs, Botches, Swellings, constant Pains, (all which are but the effects of some kind of Obstruction or other) of whatever Nature or Kind, by adjusting only their Quantities rightly, but that is the Work of an able Physician.

Now for answer to the Question which gave occasion to this Discourse: Mercurial Medicines were exceedingly useful and wou'd answer the whole design in Curing Fevers, were it not upon these two Accounts. 1. Before they cou'd be effectual for this purpose, they ought to be Administred in a large quantity, which never misses (by the violence and force of the Motion of the Blood thereby occasion'd) to induce a new Fever in the Patient of ••∣self, so that instead of Curing the former Fever, it wou'd double it, and make the danger double, which by no means is to be done; the Patient having enough a do to wrestle with one. But, 2. It requires so long time to bring the effects of Mercurial Remedies to any height, that the Patient (in so long a space) wou'd be Cur'd by the force of Nature, or kill'd by the Violence of the Disease, so that upon this account they are rendred useless. Besides there are a Thousand other Inconveniencies which render this Method in its full force, altogether impracticable.

After all, I remember to have been told (some time ago) by that Eminent Physician of our Countrey, (whom I have thrice already mention'd) That People who have been severely flux'd, seldom fall into dangerous Fevers, and that in Fevers of Children occasion'd by Worms, Mercury, if discreetly us'd, is always, and in some Fevers of riper years, is often, very successful. The Reason of both which is very evident from our Doctrine.

For, in those who have been severely Flux'd, the Blood is so purify'd, and render'd so Fluid, and all the Canals are so cleans'd and scour'd, that if at any time there shou'd happen such Obstructions as occasion Fevers, Nature is able in a short time to drive them away, seeing they must rather happen from some external cause, than from within, where all is clear and passable.

As for Fevers occasion'd by Worms among the Fluids in the Bodies of young Persons, (which by the way is an Argument omitted for our Theory of continual Fervers, as is likewise the Febris Variolarum, both which are occasion'd by Obstructions, as is evident from the botches which break out upon the latter, and as shall be just now shown of the former) For here a little Worm being forc'd into some of the capillary Arteries, where it can neither get back nor forward, totally occludes the passage of the Blood, and thereby occasions a Fever after the manner already explain'd. Now the Reason why the natural force of the Blood is not able to remove such an Obstruction is, because a living Creature makes it, which will not be mouldred away after the manner of Coagulated Blood; But will require the greater weight and force the Mercury to kill it first, and then both the Mercury and Blood concuring, wash it away.

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A new theory of continual fevers: Wherein, besides the appearances of such fevers, and the method of their cure; occasionally, the structure of the glands, ... are mechanically explan'd.

Cheyne, George, 1673-1743.

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http://ota.ox.ac.uk/id/4305

ID [isbn10]

1106013042

ID [isbn13]

9781106013040

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K049569.000

ID [BIBNO]

CW3307863753

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0384600200

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— A new theory of continual fevers: Wherein, besides the appearances of such fevers, and the method of their cure; occasionally, the structure of the glands, ... are mechanically explan'd., Cheyne, George, 1673-1743.. [8],123,[1]p. : ill. ; 12⁰. London :: printed, and sold by H. Newman, and J. Nutt,. 1701.. [Anonymous. By George Cheyne.] [Reproduction of original from the British Library.] [English Short Title Catalog, ESTCT55643.] [Electronic data. Farmington Hills, Mich. : Thomson Gale, 2003. Page image (PNG). Digitized image of the microfilm version produced in Woodbridge, CT by Research Publications, 1982-2002 (later known as Primary Source Microfilm, an imprint of the Gale Group).]

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