THE General and most effectu­al cause of all Fevers, is the Obstruction or Dilatation of (the [Page 12] 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 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.

[Page 14]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 [Page 15] 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.

[Page 16]§ 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 [Page 17] 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 [Page 18] 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 [Page 19] 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 [Page 20] 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.

[Page 21]§ 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 [Page 22] 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.

[Page 23]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 [Page 24] 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 [Page 25] 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 [Page 26] 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 [Page 27] 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. [Page 28] 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 [Page 29] 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) [Page 30] 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 [Page 31] 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 [Page 32] 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 [Page 33] 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,

[Page 34]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 [Page 35] 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 [Page 36] 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 [Page 37] 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,

[Page 38] 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.

[Page 39] 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 [Page 40] 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.

[Page 41]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.

[Page 42]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

[Page 43]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. [Page 44] 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 [Page 45] 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 [Page 46] 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, [Page 47] 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 [Page 48] 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 [Page 49] 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 [Page 50] 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: [Page 51] 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 [Page 52] 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 [Page 53] 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 [Page 54] 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 [Page 55] 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 [Page 56] 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 [Page 57] 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 [Page 58] 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 [Page 59] 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 [Page 60] 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.

[Page 61]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,

[Page 62]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 [Page 63] 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 [Page 64] 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 [Page 65] 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 [Page 66] 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,

[Page 67]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, [Page 68] 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 [Page 69] 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 [Page 70] 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; [Page 71] 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: [Page 72] 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 [Page 73] 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 [Page 74] 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 [Page 75] 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 [Page 76] 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, [Page 77] 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 [Page 78] 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, [Page 79] 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 [Page 80] 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.

[Page 81]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 [Page 82] 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: [Page 83] 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, [Page 84] 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, [Page 85] 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 [Page 86] 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 [Page 87] 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 [Page 88] 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 [Page 89] 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 [Page 90] 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 Medicaments 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.

[Page 91] 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 [Page 92] 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 [Page 93] 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, [Page 94] 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 [Page 95] 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, [Page 96] 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 [Page 97] (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, [Page 98] 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 [Page 99] 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 [Page 100] 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 [Page 101] 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, [Page 102] 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 [Page 103] 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 [Page 104] 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 [Page 105] 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 [Page 106] 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 [Page 107] 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 [Page 108] 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 [Page 109] 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,

[Page 110]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 [Page 111] 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 [Page 112] 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 [Page 113] 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 [Page 114] 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 [Page 115] 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 [Page 116] 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 [Page 117] 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 [Page 118] 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 [Page 119] 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 [Page 120] 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 [Page 121] 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 [Page 122] 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 [Page 123] 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.