[1]A NEW THEORY OF Continual FEVERS.

THE General Propoſition.

THE General and moſt effectu⯑al cauſe of all Fevers, is the Obſtruction or Dilatation of (the [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 Ob⯑ſtructed 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 be⯑ſtow, to apply this Propoſition to all particular kinds of Fevers; tho' I am ſufficiently ſatisfied it will account for All. I ſhall here only (as an earneſt of the reſt) ſhow how to apply it to continual Fevers, and therefore contract the General into

The Particular Propo⯑ſition.

THE moſt effectual Cauſe of continual Fevers, is an ob⯑ſtrution of the Glands, which will neceſſarily augment the Quantity of the Blood and Liquidum Nervo⯑rum, in the paſſable Canals and perhaps (by the Stagnation of the Fluids contain'd in theſe) ſo viti⯑ate 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 aug⯑mentation 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.

[14]Suppoſing the Glands Obſtru⯑cted, 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 Li⯑quors, per Lemma 1. and its Scholi⯑um. Wherefore it will hence fol⯑low,

§ 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 Arte⯑ries 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 Quan⯑tity of the matter whence the Li⯑quidum [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 Li⯑quidum Nervorum thereinto is like⯑wiſe obſtructed; and therefore, per Lemm. 1. there will be a grea⯑ter 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 ſub⯑ſtance and Fibre of the Brain, will (they being more than ordinarily diſtended) preſs them more than ordinarily and make a more pow⯑erful and plentiful derivation of the Liquidum Nervorum into the places whither it can flow.

[16]§ 2. From the ſame cauſe the inequality or Interruption of the Puiſes is evident: For if the fore⯑ſaid Preſſions upon the Nervous Fi⯑bres of the Brain be ſo ſtrong, that it either partly or totally occludes the paſſage of the Liquidum Ner⯑vorum; 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 inequali⯑ty 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 there⯑by cauſe an irregularity in the Pulſe. Add to theſe, what may proceed from the thickneſs of the Blood (it being contracted into a [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 Di⯑ſtractions of the tender Veſſels of the Brain, and from the great preſ⯑ſure 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 ac⯑counts, 1. Becauſe there is a grea⯑ter 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 con⯑ſidering [18] the thereby produc'd greater Ve⯑locity) 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 natu⯑ral Heat muſt thereby be kept in, and conſequently the whole aug⯑mented per Lemm. 1. Hence pro⯑ceeds our unquenchable Thirſt; the Humidity (i. e. the thinneſt parts) being more ready to eva⯑porate (ſince now the ordinary paſſages are obſtructed) the reſt muſt be proportionally dryer.

§ 5. The difficulty and fre⯑quency of Reſpiration, and the violence of expiration, is hence ea⯑ſily accounted for: The quantity [19] of Blood being augmented, there muſt a proportional greater quan⯑tity thereof be deriv'd into the Ar⯑teries of the Lungs; and ſince every one of the little Veſicles of the Bron⯑chi lye betwixt two Arteries thus inflated, it will be harder to expli⯑cate 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 aug⯑mented, both by the greater quan⯑tity 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 Ob⯑ſtruction [20] of the common paſſages, the humidity is evaporated, and the extraordinary Heat ſtiffens the Fi⯑bres 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 ne⯑ceſſary to bring it on; but moſt of all becauſe (by the plenty of the Liquidum Nervorum) all the Muſ⯑cles both involuntary and volunta⯑ry (eſpecially thoſe who want An⯑tagoniſts) are in continual violent motions which muſt neceſſarily hinder Sleep.

[21]§ 8. Ravings proceed from the diſorders in the Head, accounted for § 3. The Nerves being diſtra⯑cted 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-co⯑lour'd Urine proceeds from the velocity of the Blood, which ſepe⯑rates 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 un⯑der 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 [22] the ſtrength of Nature, then, ſeeing the greater Quantity and Velocity of the Blood produce a greater Momentum, by the frequent con⯑cuſſions and force of this, the Ob⯑ſtructions 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 af⯑terwards ſhown.

1. Thus I think I have accoun⯑ted for all the appearances of Con⯑tinual Fevers; which I reckon one conſiderable argument for our The⯑ory.

[23]2. All we ſee done in the diſſo⯑lution or ceaſing of ſuch Fevers, is the opening the Glands, the driv⯑ing out the ſtagnated Fluids there⯑in 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 diſ⯑eaſe, 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 Li⯑vidity in the internal Glands; Par⯑ticularly, of the Lungs, the Liver, the Spleen and the Meſentery; as has been obſerv'd by Borelli and others. Vide Borelli de Motu Ani⯑mal. Part. 2. prop. 227. This is one ocular demonstration of our Theory; and if the other Glands [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 Per⯑ſpiration, then by removing this obſtruction, i. e. by encreaſing the inſenſible Perſpiration, Fevers will be more probably cured, than by encreaſing all the ſenſible evacuati⯑ons: 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 Se⯑ction, De Febribus. He there ſhews [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 ac⯑counted for from the firſt of theſe, to wit, the encreaſs or diminution of the quantity of the Blood.

6. Amputations, Wounds, Fra⯑ctures, and the like, wonderfully confirm this Doctrine. For there, a conſiderable number of the Blood⯑veſſels are ſtopt, and cannot make [26] their Circle, and conſequently en⯑creaſe 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 oc⯑caſion a more plentifull derivation of the Liquidum Nervorum. But if the quantity of Blood be not ſup⯑pos'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 Obſtru⯑ction 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 pro⯑ceeds; Beſides this Fever may be encreas'd to ſuch a degree as to differ little in its ſymptoms, violence, or duration, from other more dan⯑gerous continual Fevers, which is a [27] clear demonſtration of our Do⯑ctrine; For ſince an evident Ob⯑ſtruction of the Glands produces Fevers ſo very like the moſt dan⯑gerous ones; why may we not conclude that ſome latent and un⯑known cauſe may produce ſo ge⯑neral 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 ex⯑ceſſive Gleams of Heat This is ſo true, that all Travellers aſſign this as the cauſe, having conſtantly ob⯑ſerv'd their Fevers to ſucceed ſuch ſudden changes of the Air. A preg⯑nant Inſtance of which we have in Phil. Tranſ. For Decem. 1669 N. 259. [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 Sud⯑den 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 Di⯑late them, but (by the aſſiſtance of the natural action of theſe, which is Secretion) Exhale their reſpective [29] Liquors, making them ſtill flow, ſo long as the exceſſive Heat con⯑tinues, 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 Contrac⯑tion of their Orifices and Congelati⯑on 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) [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 ex⯑actly (in proportion to our Cli⯑mats) in the ſtate of thoſe betwixt the Tropicks. Our Summer-Day heats were more violent than had been obſerv'd among us in the Me⯑mory of men, and our nights had no ways the Heat proportionate to our days: Beſides we had often ſud⯑den changes, which tho' not ſo Violent as in theſe warmer Coun⯑treys; Yet had the ſame (tho' a ſlower) effect as among them: And therefore it was that frequent Vo⯑mitings 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 [31] Countreys, and the neceſſity there⯑of will be underſtood when we come to ſpeak of Vomiting. The ſame practiſe obtains in Fevers occaſion'd by ſurfeiting or Drun⯑kenneſs; which is ſtill to be ſuſ⯑pected 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 conti⯑nu'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 ac⯑countable from any other Theory (as I think) how theſe Liquors which are ſecreted from the Glands at the Diſſolution of Fe⯑vers, could be ſo different from the [32] ordinary fluids which are there excern'd. From ours it is evident, for an Obſtruction of the Glands muſt neceſſarily make their reſpe⯑ctive 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 Opini⯑ons about continual Fevers.

The moſt common and gene⯑rally obtaining Opinion about Fe⯑vers is, that they are more imme⯑diately 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 [33] adduced) this one Argument.

When any Corrupt Matter is mix'd with the Blood, ſo as to vitiate the whole maſs, (as Vine⯑gar 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,

[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 lei⯑ſurely 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 ſe⯑cern 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 [35] things without recurring to mira⯑cles, 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 [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 Ope⯑ration and effects of Vomiting.

2. That it is at leaſt poſſible, this Morbifick matter may be de⯑riv'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 [37] motion of the Nerves, the neceſſi⯑ty 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 La⯑cteals.

To decide the matter, I muſt ſuppoſe my Reader to have con⯑ſider'd the 2 laſt prop. (Ex ijs quae ad ſeparationes) which Beilini has in his Preface to his Book De Ʋri⯑nis & 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,

[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 Contor⯑tion thereof; that the Blood may be the more eaſily propogated through the ſame: But this is com⯑mon to all the Arteries and Veins, whereby, without any Interrupti⯑on of the ſame ſpire, the propaga⯑tion of the Blood, in the former, from the heart to the extremities of the Body, and from the extre⯑mities 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 Arte⯑ry after theſe windings degene⯑rates into a Vein.

[39] Prop. 2. That ſeparation or ſe⯑cretion is perform'd by the compo⯑ſition of two motions in the Fluid; one propagated through the length of the Canal, another tranſverſly through its ſides (for it is demon⯑ſtrable that all Fluids preſs undi⯑qua (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 di⯑rection) of the ſeparated Fluid.

Prop. 3. That in a mixt Fluid, conſiſting of greater and leſſer co⯑heſion 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 great⯑eſt [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 ſe⯑cretory 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 compound⯑ed 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 Demon⯑ſtration of this Propoſition; refer⯑ring (that of) the reſt to their Au⯑thor.

[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 ſepara⯑ted 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 fol⯑lowing

COROLLARIA.

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

[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. pe⯑culiar to ſuch lengths and compli⯑cations, 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

[43]5. That Secretion may be per⯑form'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. Com⯑pleat the Parallelogram ABCD. [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 al⯑ter'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, ob⯑tains in Animal Bodys; For tho his demonſtration be only concerning Convex Cones, yet the ſame ob⯑tains in Concave ones; wherefore ſeeing the Artery betwixt any two Branchings is a Conus Truncatus, it may be repreſented by the fi⯑gure CEBGF; Now ſeeing the Diameter CB of the baſe of this [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 Bi⯑ſect the di⯑ſtance OD in Q; and if it be found (having drawn CQ) that QS is e⯑qual to QC, then the Conus Truncatus CE BGF (among all of the ſame Baſe and Alti⯑tude) gives the leaſt reſiſtance to the Blood flow⯑ing from O to D.

I am enclin'd to think this may obtain in the truncks [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 Cir⯑cumvolutions in one of theſe, Proxi⯑me. He likewiſe aſſerts, That (cae⯑teris paribus) if two Fluids of the ſame Nature, with equal Veloci⯑ties, [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 ſup⯑poſe 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 circu⯑lar; (which perhaps may follow from this, That ſeeing a Circle is the only ordinate figure of an infi⯑nite 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 [48] conſequently the only Curve in which a Fluid would moſt eaſily turn) and likewiſe the Arch in which they turn to be a Semicir⯑cle: (which it muſt be, if the ſides run Parallel after the turning; and Univerſally, if the ſides produc [...]d make any Angle from the quanti⯑ty thereof, the quantity of the Arch in which they turn, may be deter⯑mined.) 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 [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 [50] ſuppoſe the Proportion of the Co⯑heſion 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 immediate⯑ly ſeparated. For when it has lodg'd any time in the Veſiculae ſpermaticae, we know by its Ebulli⯑tions 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 Mi⯑croſcopial Obſervations he has made on this Fluid, its Fluidity is little leſs than that of common Water: [51] And conſequently, at leaſt, Ten times more than that of our Mor⯑bifick matter.

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

PROPOSITION.

LET two Drops of two differ⯑ent 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 Compara⯑tive Gravities; and by the ordina⯑ry Method, you may likewiſe have their Specifick Gravities. Theſe being given; I ſay, their Viſcidity and Coheſion ſhall be in a com⯑pounded Proportion of their Spe⯑cifick [52] Gravities reciprocally, and their comparative Gravities direct⯑ly. 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 Allow⯑ances; 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 Celeri⯑ty of the Blood, when it firſt en⯑ters the Plications of the Teſticulus Humanus; (which all will readily [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 Sto⯑mach 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 Viſ⯑cidity 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 Cele⯑rity 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 [54] Fluid ſeparated in the Teſticulus Humanus, were to that of our Mor⯑bifick as 1 to 10, then the ſmall In⯑testines ought to be Five Hun⯑dred times longer than they are. And indeed I believe the Propor⯑tion 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 o⯑therwiſe; 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 remem⯑ber, Dr. Liſter, ſome where in the Phil. Tranſ. relates how he try'd to get in a very fine ting'd Spirit [55] into the Lacteals of a live Dog, by cuting the ſmall Guts, and inject⯑ing 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 Tin⯑ctures; for this is the Natural Co⯑lour 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 La⯑cteals. 2. That the Periſtaltick Motion and the Valves of the In⯑teſtines may hinder the quick mo⯑tion 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 Mor⯑bifick matter. 4. That there is re⯑really [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 advan⯑tage 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 recipro⯑cal, it adds as much (to the mo⯑tion 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 circumvo⯑lutions of theſe Inteſtines (which we have conſider'd) being only to [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 like⯑wiſe know, that all theſe Medica⯑ments are diſſolv'd into a thin Li⯑quor by heat (as Turpentine, But⯑ter, &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 ſome⯑time in the Conſervatory of the Gland; for then the Aqueous and more humid Parts evaporate; and by its ſtagnation it acquires an in⯑eptitude to motion: And tho the [58] Blood flows very eaſily in the Ar⯑terys and Veins; yet I defy any to cauſe extravaſat Blood enter its Veſſels again. But more particu⯑larly, we muſt conſider the Liver to be a very large Veſſel, and (if it were evolv'd) to make an Ar⯑tery 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 mo⯑tion of the Blood there being very ſmall: But ſtill I aſſert it is not near ſo vicid as our Morbifick mat⯑ter. 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 Eva⯑poration of the Humidity, which occaſions both; the ſame might be ſaid of the Purulent matter which [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 Evacuati⯑ons; under which head I compre⯑hend 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 forementi⯑on'd [60] Books together; that it were equally impoſſible as impudent to offer at any additions: And there⯑fore for intire ſatisfaction on this head, I ſhall refer my Reader to theſe Books.

2. As to Vomiting; I ſhall com⯑prehend 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 Vo⯑mitorii: 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 mat⯑ter is not in the cavity of the Sto⯑mach (at leaſt in ſuch plenty as it is excern'd by a forc'd Vomit) be⯑fore the ingeſtion of the ſaid Vo⯑mit. 4. I ſhall give the whole de⯑ſtruction and connexion of this Operation; And, 5. Shall conſider the advantages of the ſame in the cure of Fevers.

[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, where⯑by the particles thereof are diſpos'd to make a real diviſion or a violent inflexion of the Nervous and Mem⯑branous Fibres of the Body, which occaſions frequent and forceable reciprocations, ſucceſſions and de⯑rivations of the Liquidum Nervo⯑rum into the Muſcles and contra⯑ctile Fibres of the Canals; where⯑by all the involuntary Muſcles are brought into violent contractions, and the emiſſaries of the Glands are ſqueez'd.

Thoſe who deſire a fuller ac⯑count of the nature and mechani⯑cal 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,

[62]1. Vomiting is Partly produc'd by this vis ſtimulans Vomitorij; This is evident from theſe conſide⯑rations. 1. Becauſe ſometimes we immediately Vomit upon the In⯑geſtion 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 mix⯑ture; which could not happen, if the Morbifick matter had concur'd to produce the fit. 3. Sound per⯑ſons (in whoſe Stomachs there is little or none of this Morbifick matter) often Vomit upon a too plentiful ingeſtion of an (other⯑wiſe) inoffenſive Liquor. The on⯑ly reaſon of which muſt be that the Stomach not being able to de⯑rive into the Maſs of the Blood the ſaid Liquor, ſo faſt as it is pour'd in, it muſt Sowr on the [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 vio⯑lent 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 ſeve⯑ral things loſe the quality to pro⯑duce their viſible Effects, when in ſmall, which they had when in great. But, 2.

I ſay, Vomiting is moſtly acca⯑ſion'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 be⯑ing terminated at, or near the in⯑ternal ſurface of the Stomach, af⯑ter [64] one or two plentiful fits of Vo⯑miting, (there being produced thereby ſuch a ſuccuſſion and compreſſion of the ſides of the Stomach) theſe Particulae Stimu⯑lantes muſt neceſſarily be diſentan⯑gled; 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 ef⯑fect; and therefore it muſt neceſ⯑ſarily be produc'd by the vellicati⯑ons of the Morbifick matter ex⯑cern'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 [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 ordina⯑ry Arithmetical Progreſſion, 1. to 2. or 1. to 3. or 2. to 3, &c. This is evident in the uniſone or con⯑cordant Strings of greater Muſical Inſtruments: And the Reaſon is, becauſe thereby the Oſcillations of ſuch Bodies become Commenſura⯑ble. 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 [66] Stomach, whereby they are brought into motion, and conſe⯑quently 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 Vo⯑miting: 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 Stimu⯑lans 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,

[67]3ly. That the Morbifick matter (excern'd by Vomiting) is not exiſt⯑ent in the Cavity of the Stomach, (at leaſt in ſuch Plenty at it is ex⯑cern'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 ex⯑cern'd Morbifick matter; and ſince (as has been already proved) it can not be the former, it muſt of neceſ⯑ſity be the latter: Wherefore if the Morbifick matter were already ex⯑iſtent in the cavity of the Stomach, [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 how⯑ever violent the conſequent fits were, which is likewiſe contrary to experience. The force of the Muſ⯑cular Fibres of the Stomach, The Muſcles of the Abdomen and Dia⯑phragm (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 [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 Mor⯑bifick matter already in the cavity of the Stomach; It is Impoſſible to give an account of the different effects of different Vomits: For Ex⯑ample, why an Antimonial Vomit does excern this Morbifick matter more plentifully than Whey or warm Water. For if before the In⯑geſtion 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 Vo⯑miting: 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 [70] Vomiting; and that with equal violence (by taking their Quan⯑titys 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 propo⯑ſition.

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, adja⯑cent to the ſurface of the Stomach, do dilate the ſame (which by ſome extrinſick cauſe) had been contract⯑ed 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 Secre⯑tion; [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 Momen⯑tum of the Glands; The matter muſt neceſſarly flow into the Ca⯑vity of the Stomach, till it be ac⯑cumulated in ſuch a Quantity (which not being to be done in an inſtant, muſt require ſome time) as is ſufficient (by the united loath⯑ſomeneſs 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 vio⯑lent contraction, and thereby throw all out by the Oſophagus, which brings all to quiet again, Till there be a new, a ſufficient quanti⯑ty exerned from theſe Glands to re⯑produce the foreſaid Contraction: [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 lon⯑ger able to elicit the Morbifick mat⯑ter 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 con⯑ſiderable time before it operate, there often paſſes ſome part there⯑of from the Stomach into the Inte⯑ſtines, and occaſions a gentle Purge, by diſſolving the Faeces, and velli⯑cating the Fibres of the Inteſtines, as ſhall be more particularly ſhown when we ſpeak of Purging. How⯑ever 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 [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 Thou⯑ſand weight, may and often does, take away the Obſtructions in ma⯑ny 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 Vo⯑miting 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 princi⯑pal [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 oc⯑caſion'd by Intemperance, the Sto⯑mach is the Scene where this great Miſchief is both contriv'd, and put into Execution; the Obſtructi⯑on of the Glands thereof, being the firſt and principal Cauſe of theſe Fevers; And in Fevers occaſion'd by Cold, the Stomach and Inte⯑ſtines being moſt Expos'd, and leaſt Defended from the Cold Air, receives its firſt and ſtrongeſt Im⯑preſſions; which two (as formerly was ſaid) have the moſt conſide⯑rable ſhare in the cauſe of our Con⯑tinual 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 [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 conſide⯑rable a part of the Cauſe, enables Nature to perform the reſt very ea⯑ſily. 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 wind⯑ing Canal, which is continued from the Mouth to the Sphincter ani,) and is conſequently leſs dan⯑gerous than thoſe which run the Circle of the Blood; For it is not to be doubted, that all Alterative Medicines have more or leſs dan⯑ger in them (from the effect of [76] their Stimulations upon the Nerves, their Fermentations with the Blood, their Separating, or Pro⯑moting the Natural Coheſions of the Liquors of the Body, and their many other unknown Producti⯑ons.) 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 Veſ⯑ſels of the internal Surfaces, by the violent Concuſſions of the Body, occaſioned by Vomiting; but this is eaſily prevented by Blood-let⯑ting, [77] which ought always to pre⯑ceed the plentiful uſe of vomito⯑ries in all Diſeaſes. Beſides, ſome⯑times 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 (conſe⯑quently the violence of Vomits, as of all other Medicines) ought to be adjuſted by this Proportion, Viz. They ought to be in a compound⯑ed 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, Purg⯑ing; In explaining of which, I ſhall, 1. Shew that Vomitive and Purgative Medicines differ only in [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. Con⯑ſider its uſe in the Cure of Fevers. I ſay then,

1. That Vomitive and Purga⯑tive Medicines, differ only in the degrees of the ſame Quality, i. e. Purgative Medicines, by encrea⯑ſing their force vaſtly, and confin⯑ing it to a leſſer Quantity, either of a Fluid or ſolid Body, become Vo⯑mitive, 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 In⯑teſtines, does frequently Purge us. 2. The ſame Medicines (for ex⯑ample, [79] Vinum Emeticum,) taken by the Mouth, will provoke Vo⯑miting, which giv'n by way of Gliſter, will Purge: The ſame obtains in all ſtrong Emeticks. In ſhort, all ſtrong Medicines of ei⯑ther kind conſtantly produce both theſe Effects. The reaſon of all which is this; If the Medica⯑ment of either kind be ſo ſtrong as immediately to vellicate and ſtimulate the Fibres of the Sto⯑mach, 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 Mo⯑tion of Digeſtion, it goes by the Inteſtines, and diſſolves the Cohe⯑ſion 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 im⯑poſſible [80] in any other Theory, to ac⯑count how theſe two different Medicines ſhou'd upon the ſame Parts produce different Effects; For both theſe Medicines are ta⯑ken by the Mouth, go down the Oſophagus, and enter into the Sto⯑mach either in the form of a Li⯑quid, or are there by it reduc'd in⯑to 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 im⯑poſſible to explain the manner of this, without ſaying the one acts more powerfully and forceably, and makes more violent Contra⯑ctions, 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.

[81]2dly: The account of the ſeve⯑ral ſteps, and of the manner of this Operation, is thus; Purgative Me⯑dicines, being receiv'd into the Mouth, and admitted into the Sto⯑mach, their particles vellicate and ſtimulate the Fibres thereof, and thereby encreaſe the digeſtive fa⯑culties, i. e. bring the Muſcular Fi⯑bres of the ſtomach, the Muſcles of the Abdomen and Diaphragm into more frequent contractions than ordinary, till they are admited in⯑to the Inteſtines, the Fibres and Glands of which being more ſenſi⯑ble 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 [82] Fluid which lubricates the Paſ⯑ſages; and mixing with the fecu⯑lent 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 contracti⯑ons of the Inteſtines) it paſſes more plentifully and eaſily into the Re⯑ctum, and is thence ejected. This is the uſe of the more gentle Purges which only cleanſe the In⯑teſtines. 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 there⯑with produce many unnatural fer⯑mentations therein, ſeparating or promoting the natural Coheſions of the Liquors of the Body, and accaſioning many other unknown effects, as has been formerly ſaid: [83] And likewiſe there, vellicating the ſpiral Fibres of the Arteries and Veins, bring theſe into more force⯑able contractions, and thereby promote the Circulation of the Blood and make it run with grea⯑ter Velocity and force; and by this means in a ſhort time waſh away any obſtructions that either hap⯑pen to be in the more direct Arte⯑ries, or the more complicated ones which conſtitute the Glands, en⯑creaſe the inſenſible perſpiration, and purifie the Blood of all the groſſer and more noxious parts, by the Ductus Cholodochus and Pancre⯑aticus 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 Spi⯑rits, or Liquidum Nervorum ſpent, [84] ſpent, the viſible Excretions by Siege and Urine much greater, and the Body weak'ned; eſpecial⯑ly after a few days of ſuch a courſe. Whereby it is evident theſe Medi⯑cines muſt operate after the man⯑ner [...]w explained. From hence it is clear,

3dly. That the advantages of Purging in the cure of Fevers are very great, upon theſe two conſi⯑derations: 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 to⯑wards 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 obſtru⯑ctions of moſt of the other Glands, [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 vio⯑lent Purges there is a greater dan⯑ger by far than in Blood-letting. His words are, ‘Quia vero quic⯑quid eſt ſuſpicionis in miſſione Sanguinis ad ſolum fermentati⯑onem 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 cae⯑troquin eſſe poſſit: ſed res e con⯑verſo ſe habet, ſuſpicio enim ejus mali a miſſione Sanguinis eſt ſuſ⯑picio [86] rei poſſibilis non tamen neceſ⯑ſario prevenientis, aut neceſſario conjunctae, cum qualibet miſſione Sanguinis; in purgatione autem neceſſarium ſemper eſt Sanguinem ſolvi a naturalibus Coheſionibus, ſeu recedere & dimoveri a ſua com⯑poſitione; In Purgatione igitur pe⯑riculum erit certum, in venae ſe⯑ctione dubium: hoc eſt, erit Pur⯑gatio 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 ad⯑duc'd, it is evident, 1. That vio⯑lent Purges have a great deal of real danger in them abſolutely, without reſpect to other remedies; and indeed theſe unatural Fer⯑mentations and changes of the Co⯑heſion of the Fluids inſtead of pro⯑moting the cure, often encreaſes the cauſe of Fevers, to wit the ob⯑ſtruction of the Arteries which [87] conſtitute the Glands. 2. That vio⯑lent Purges are reſpectively much more dangerous than Blood-let⯑ting, wherefore this laſt is a more ſafe, and conſequently a more uſe⯑ful 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 Li⯑quors of the Body, where the dan⯑ger of any Conſiderable alteration is extreamly great. Wherefore up⯑on 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 Ca⯑nals of the Primae Viae. And how [88] much longer the firſt is than the latter, I leave the Reader to con⯑ſider. 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 Pu⯑carnij Diſſertatio de Curatione febri⯑um quae per Evacuationes inſtituitur, that thither I ſhall refer the Rea⯑der, only adding the reaſon why ſuch Medicaments Adminiſtred in [89] the begining of Fevers, do rather encreaſe than cure them, which is this: In an Obſtruction of the Glands, the Blood in the Compli⯑cated 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 Ar⯑teries which conſtitute the Glands, whereby the inſenſible evacuati⯑ons 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 [90] through the ſuperficial Arteries, and thoſe few other Glands that are (perhaps) left paſſable, the na⯑tural humidity only, i. e. the thin⯑eſt Parts of the Blood, and conſe⯑quently 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 de⯑cline of theſe Fevers, ſuch Medi⯑caments will be able to force the ſmall remainder of theſe obſtructi⯑ons 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.

[91] COROLLARIA.

1.THAT the firſt thing in⯑cumbent upon a Phyſici⯑an, 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 au⯑genda velocitas, aut refriger andum aut humectandum, aut aliquid ad⯑hoerens vaſis dimovendum aut ab⯑ripiendum.’ 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 [92] the Obſtructions of the moſt of the other Glands likewiſe This eſpe⯑cially obtains in Fevers occaſion'd by Intemperance or Cold: As is evident from what we have ſaid about Vomiting; But as for Pur⯑ging in Fevers, there is very little more ſafe than what is the ne⯑ceſſary Concomitant of all ſuch Vomitings.

3. The laſt, but moſt Univer⯑ſal, and ſureſt ſtep, is the encrea⯑ſing 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 deter⯑mined 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 [93] about the Advantages of Vomit⯑ing.

But here it may be very fairly ask'd why (ſince I make the Ob⯑ſtructions 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 reme⯑dies of obſtructions) to be one of the ſteps of the cure of theſe Fe⯑vers.

Before I anſwer this queſtion I ſhall, 1. Explain the nature of Mercury. 2. I ſhall ſhew the man⯑ner of the Operation of theſe Me⯑dicines; 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, [94] by which I underſtand an aggre⯑gate of the Smalleſt and laſt con⯑ſtituent 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 tole⯑rable about the Nature of this Mi⯑neral; 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 Mi⯑croſcope) ſtill the upper part re⯑tain'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 Mer⯑cury, in reſpect of other Fluids, and the uniform preſſure of the Medium. For all Fluids will re⯑tain their Sphericity till their [95] Quantity be ſo diminiſh'd (either by their being another Heteroge⯑neous ſpecifically lighter Body in⯑cluded in them, or by their Gravi⯑ty decreaſing at a greater rate than their Surfaces) that they are of e⯑qual Gravity with unequal Porti⯑on 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 Quick⯑ſilver among common water, in which we know a part of the Quick-ſilver is loſt, by the Dimi⯑nution of its weight, and the diſ⯑colouring and effects of this Wa⯑ter.

But the true Reaſon why the former Suppoſition is to be made, [96] is, becauſe from it ſome of the Phe⯑nomena of Mercury may be ac⯑counted for.

For, from thence it is evident, why Mercury (tho' the heavieſt known Fluid) riſes with fewer de⯑grees of Heat in an Alembick, than any other. 1. It's parts (of the firſt Compoſition) being ex⯑ceedingly 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 Sur⯑faces; for the Gravities of Bodies decreaſe in a Triplicate Proporti⯑on, whereas their Surfaces decreaſe only in a Duplicate one. Thus ſuppoſing (for Example) the Dia⯑meter of a Particle of Mercury (of the firſt Compoſition) to be to the Diameter of a Particle of Water [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 So⯑lidities, 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 Gra⯑vities 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 Suppoſi⯑tion it will follow, That the Gravi⯑ties 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 Mer⯑cury wou'd riſe in the Alembick with much Fewer degrees of Heat, than the Water upon this account. But, [98] 2. The Particles of Mercury are per⯑fectly Spherical and Equal; (for all Homogeneous Bodies muſt conſiſt of Particles Similes & aequales in the Eu⯑clidean 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 Mercu⯑ry 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 (Cae⯑teris paribus,) than that of other ſolid Bodies generated by the Circum⯑rotation of what ever Figure, Regular, or Irregular, Right-lin'd, or Curve⯑lin'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 Proporti⯑onally [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 Alem⯑bick 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 Spherici⯑ty till the ratio of the Surface of a Particle of Mercury to its Gravity, be to the ratio of the Surface of a Par⯑ticle of Air to its Gravity, as is the Specifick Gravity of Mercury to the Specifick Gravity of the Air, i. e. (put⯑ting the Specifick Gravity of Mercury [100] to that of Air, as m to n; and the Di⯑ameter 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 be⯑ſides theſe diviſions into Spherical Particles, the Saline Bodies which are mix'd with the Mercury in theſe Pre⯑parations keep theſe aſunder and dis⯑join'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 Preparati⯑ons; 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 [101] uniform heavy Fluid; which cou'd ne⯑ver 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 Parti⯑cles 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 ſtimu⯑late the more ſenſible parts of Ani⯑mal Bodies, and (conſequently) to produce Vomitings and Purging (of themſelves) according to their Quan⯑tity, and the degrees of their Natural force.

2. That the only effect of repeated Sublimations in theſe Preparations, is, [102] the diviſion of the Mercury into ſmal⯑ler Particles, and the freeing of theſe from the Groſſer and more Noxious parts of theſe Saline Bodies; for Mer⯑cury ſublimating more quickly and ea⯑ſily than theſe other Saline Bodies, muſt in repeated Sublimations have a grea⯑ter proportion to the Saline Mixture than in the firſt Sublimations, and con⯑ſequently the ſubſequent Sublimations muſt have leſs of thoſe Saline Bodies than the Antecedent, whereby the Pre⯑paration 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 perform⯑ing which, I diſtinguiſh two Caſes. 1. Either the Medicine is taken in⯑wardly. Or, 2. It is apply'd out⯑wardly; under which head I compre⯑hend both Mercurial Inunctions and Plaſterings. As to the 1. After the Medicine is taken by the Mouth, it [103] deſends into the Stomach, and there the Saline parts of the Compoſition vellicat the Fibres thereof, which oc⯑caſion 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 Vomit⯑ing, as has been formerly explain'd: The Mercury it ſelf, with ſome of the remainder of the Saline Particles ſlip⯑ing into the Inteſtines, do likewiſe vellicat theſe, and occaſion a Gentle Purge; which Effect, tho' it be con⯑ſtant (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 ſa⯑line parts of the compoſition, is evi⯑dent from the nature of Mercury, and the effect produc'd in it by the Chy⯑mical preparations thereof juſt now explain'd: For Mercury conſiſting of [104] ſpherical Particles, and by ſuch prepa⯑rations 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 pro⯑duce 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 Sub⯑limations, (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 [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 Bo⯑dies 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 Medi⯑cines, 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 ſa⯑livation 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 [106] where either it, or any Liquor (of the Body) generated by it, Flows, (the ſmall remainder of theſe Saline Par⯑ticles, which adheres to the Mercury after the action of the Stomach and In⯑teſtines, 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 Coheſi⯑ons 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 be⯑cauſe it is exceeding weighty, and makes therefore a greater and more forceable Ictus, and becauſe it's parti⯑cles are exceeding ſmall, and are there⯑fore to be conſider'd as ſo many ex⯑ceeding [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 Microſ⯑copial 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 emaciat⯑ed, till there be nothing left but pure and uſeful Liquors, and clear and paſ⯑ſable Canals. Thoſe who can only be convinc'd by occular Demonſtrati⯑on [108] may ſee a kind thereof in Phil. Tranſ. for Jan. 1700. where Leuven⯑hoeck 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 Mer⯑curial Medicines, which is noways to be forgotten; for beſides theſe men⯑tion'd Effects, it diſtroys that corro⯑ſive Faculty of the Liquors which burſts the ſuperficial Veſſels, and pro⯑duces thoſe conſtant pains, Scabs, Ul⯑cers, and the like, which we feel; For, ſuppoſing an Obſtruction in any Veſſel (either by the corroſiveneſs or Viſci⯑dity of the Liquor, or from ſome extrinſick cauſe) the Liquor Stag⯑nates and Coagulates there, and by the force of the fluent part of that Li⯑quor, and by the Corroſiveneſs of the ſtagnated part, the Veſſels are Miſe⯑rably diſtended, and their parts dila⯑cerated, which occaſions conſtant pain in that part; or they burſt, and the Liquor putrifying, occaſions a Botch, Scab, or Ulcer, more or leſs Danger⯑ous and painful, as the corroſiveneſs [109] of the ſtangnated and putrifying Fluid is greater or leſſer. Now this corroſive Faculty muſt proceed from the pointedneſs of the particles (per⯑haps 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 equa⯑ble in their Actions, and Homogene⯑ous 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 be⯑lieve) of Mercurial Medicines is Sali⯑vation, and that really the Salivary Glands ſecern more of their Fluid pro⯑portionally than any other Glands of the Body, which is contrary to the 5. Prop. about Secretion. To this I An⯑ſwer,

[110]1. That the principal effect of Mer⯑cury, is the attenuating the Fluids, the clearing the Canals, and the de⯑ſtroying the Corroſiveneſs of the Obſtructions, and that ſalivation has no more title to be the principal ef⯑fect of Mercury, than inſenſible per⯑ſpiration. For all the Glands (not⯑withſtanding the Objection) ſecret their reſpective Liquors in the pro⯑portion mentioned in prop. 5. about Secretion. 2. It is evident that ſaliva⯑tion is not the main effect of Mercury, from this, That many perſons are cur'd of very dangerous Poxes, Ul⯑cers and Rheumrtiſms without ever Salivating, at leaſt at the ordinary rate of Salivation. But 3. The rea⯑ſon 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 ſe⯑parate viſible Fluids; and conſe⯑quently it is but reaſonable they ſhou'd ſecern more than any other. It is true the Glands of inſenſible per⯑ſpiration are more in number than thoſe, and it is not to be doubted but [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 Ca⯑nals 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 mention⯑ed Prop. why they ſecern more plenti⯑fully. 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 Contex⯑ture, and ſo obvious a courſe as in o⯑thers: 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 be⯑ing a tough ropy Subſtance, cannot be thruſt out ſo faſt as the Mercury car⯑ries it forward, eſpecially ſeeing it ſeperates only the moſt Glutinous [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 Sali⯑vation continues only ſo long as any of the Glands are found ſwell'd. Whence it is evident that this plenti⯑ful Salivation depends upon this, That the Fluid is as it were laid up in ſtore to be deriv'd more plentifully after⯑wards, 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 Salivati⯑on by Mercury.

2. As to the ſecond Caſe: In Mer⯑curial Inunctions the viſcid Matter, in which the Quick-ſilver is wrought and pounded, ſerves only to keep the ſmall Particles thereof ſeparated and [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 Conſti⯑tion of the Patient, (for the Quantity of Mercury, which will kill one, will not produce the deſign'd effect of Sa⯑livation in another) by this Method, as exactly as by Adminiſtring it gradual⯑ly in Doſes, by the Mouth. But it can⯑not be done ſo, and therefore the lat⯑ter courſe is the more ſafe.

Mercurial Plaiſters apply'd outward⯑ly to heal Scabs; or inveterate Ulcers, operate thus; The Coroſive ſaline mix⯑ture, if there by any part thereof in the Compoſition, eats away and cor⯑rodes the putrid Matter, which ſears up the Mouths of the Veſſels; ſo that the Mercurial Particles get eaſily into [114] them, where they both clear the Veſ⯑ſel 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 Operati⯑on, and of the Effects of Mercurial Me⯑dicines, when the Mercury enters in a⯑ny Quantity into the maſs of the Blood, and from thence it will be eaſily un⯑derſtood, that when the quantity is leſs, the Effects will be proportionally leſſer: Sore that it will be needleſs to explain all the ſeveral degrees there⯑of 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 Mer⯑cury, to the Efficacy of the Blood of it ſelf and unaſſiſted to take a⯑way [115] Obſtructions. Firſt, Then we muſt conſider, if inſtead of the ordi⯑nary Liquors there paſs'd nothing but Mercury in the Canals of the Body, the weight of Blood being to that of Mer⯑cury, 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 Ob⯑ſtruction than the Blood of ſelf: But it is certain (if the Obſtruction ren⯑ders the Canal impaſſible,) there can no Particle of the Mercury get away; and (when there is any quantity there⯑of 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 no⯑thing 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 [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 E⯑laſticity) and thoſe of Mercury are not, or very little ſo: And conſe⯑quently upon this account, the Effica⯑cy 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 Pro⯑portion 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 [117] of Curvity, is to be conſider'd as theſe Angles, when theſe ſpheres are conſi⯑der'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 Par⯑ticle 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 Li⯑quors of the Body are exceedingly at⯑tenuated 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 fre⯑quent 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 [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 re⯑move 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 li⯑beral 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 re⯑moval 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 Ob⯑ſtruction, that it will continually en⯑creaſe [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, ei⯑ther 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 (per⯑haps all continual) Fevers, the Li⯑quors (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 de⯑ſtroying the Viſcidity and Thickneſs, the Corroſiveneſs and Pointedneſs, of the Particles of the whole Liquors of the Body, rendring them Fluid and [120] moveable, Innocent and Harmleſs, if before they were otherwiſe.

2. They are evidently uſeful for re⯑moving all Obſtructions, Ulcers, Scabs, Botches, Swellings, conſtant Pains, (all which are but the effects of ſome kind of Obſtruction or other) of what⯑ever Nature or Kind, by adjuſting on⯑ly 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 exceeding⯑ly 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 in⯑duce a new Fever in the Patient of [...] ⯑ſelf, ſo that inſtead of Curing the for⯑mer Fever, it wou'd double it, and make the danger double, which by no means is to be done; the Patient hav⯑ing enough a do to wreſtle with one. But, 2. It requires ſo long time to [121] bring the effects of Mercurial Reme⯑dies 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 Vio⯑lence of the Diſeaſe, ſo that upon this account they are rendred uſeleſs. Be⯑ſides there are a Thouſand other In⯑conveniencies which render this Me⯑thod in its full force, altogether im⯑practicable.

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 occaſi⯑on'd by Worms, Mercury, if diſcreet⯑ly us'd, is always, and in ſome Fevers of riper years, is often, very ſucceſs⯑ful. The Reaſon of both which is very evident from our Doctrine.

For, in thoſe who have been ſevere⯑ly Flux'd, the Blood is ſo purify'd, and render'd ſo Fluid, and all the Ca⯑nals are ſo cleans'd and ſcour'd, that if at any time there ſhou'd happen [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 Obſtructi⯑ons, 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 capil⯑lary Arteries, where it can neither get back nor forward, totally oc⯑cludes 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 [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.