A vindicatory schedule concerning the cure of fevers containing a disquisition theoretical and practical, of the new and most effectual method of curing continual fevers, first invented and delivered by the sagacious Dr. Tho. Sydenham : also shewing by way of preliminary, the indispensible charge lying on physicians to improve themselves and the art ... : with an appendix of Sanctorius his Medicina statica ... / by Andrew Broun, M.D.

SECT. VII. Containing a New and Mechanical Hypothesis of the Essence of Fevers, with the cause effici∣ent and occasional of the frequency of the Pulse, and that matterial or occasional cause also far∣ther Mechanically traced.

IT seems very probable, that all the Physicians hold∣ing the former Opinions have Erred, and the Fountain of all their mistakes appears to be that fundamental error, as the acurate Bontikoe observes, that they took the imme∣diate efficient cause of the motion of the heart to be the blood, and that the frequent mo∣tion thereof and the Arteries, did alwayes depend upon some alteration of that blood; but that this must be otherwayes seems plain, because the Heart of some Animals being cut out when they are alive, and holden in the hand, will beat a long time without a drop of Blood: So the mo∣tion of the Heart seems not to depend on the Blood, but on some other cause, per∣haps on the influx of the animal Spirits, pro∣ceeding from the Brain, by the remainder

whereof inviscate in the Heart, the motion seems to be continued after the separation thereof from the Body.

The next fundamental Error, and obser∣ved likewayes by the same Author, seems to be, that they esteemed the intension of Heat alwayes to depend on the rapide ef∣flux or circulation of the Blood; and that it was both a sign and effect thereof: The con∣tracy of which appears by an Inflamation or Tumour, where the Member affected is vexed with a great Heat, and kind of Fever▪ which is oft times communicate to the whole Body, and here it is clear, that the Blood is rather stagnant then swiftly moved, and the Fever that is communicate from the Inflamation, certainly shewing a near resemblance betwixt them, perswades that a certain degree of Incrassation from this Foun∣tain of Co-agulation: And accompanied also with a frequent Pulse, does affect the Blood, as the Ignorance then of the concur∣ring occasional cause of that frequency of the Pulse, gave rise to all the Errors about this subject, so the bringing to Light the true cause thereof, will make all these Er∣rors evanish.

For clearing then of this, it is to be considered, that the Body

of Man being a curious Ma∣chine the motion wherewith it is en••ue••, like other Machines as it has an efficient cause, so it has a final cause thereof; And in respect the final cause is alwayes the reason of placing the efficient cause, and that the Idea thereof is still in the mind of the Architeck before the Idea of the efficient; This makes the Idea of the efficient to be alwayes shaped subser∣vient to the Idea of the final Cause; And must also make the structure of the efficient in the Fabrick of the machine to be moulded to that final Cause likewise, & instructed & qualified Suitable to attain the end of the motion, that is to say, that it may have a faculty of Intension and Remission to be regulate and moderate according to the exigence and necessity of the final, to be productive of the end of its being put there; At least in so far as the Contrivance of a Mechanism will go: As in a Watch whose Spring is so contrived that it may be Bended or Slack∣ned for attaining the end of its motion. And it seems also probable that in every motion in Nature, its only the end that both puts the Efficient, and sets it a going; and therefore it must be still by that end, that the motion must be regulate, Hightned or diminished:

As it is seen when Mariners do exercise the Pump of the Ship, its alwayes with respect to the breaking in of Water at the Leaks; Which being in great quantity does excite to frequent and vigorous Pumping to save the Ship.

Much after the same manner it seemes probable that this motion of the Heart which is nothing but a Pump designed to lay in the alimentitious Juice, and so has for its end a proportionable proportional reparation of the functions and parts suitable to their Consumptsion and Waste; And that by the sending to them throw the Chan∣nels of the Arteries the arterial Blood, which is to be dispersed in such quantity and time, as may answer to the reparation of their Consumptsion and Waste; The Body consist∣ing, which seemes to deny it all consist∣ance, in a continual Flux, and succession of new parts coming in place of the old that are wasted, like a River which has nothing Identitious but the Channel: And so this final cause would seem to require an efficient whither that be the first Impellent, the Archeus or Spirits indued with a capacity and apti∣tude not only to continue, but also to in∣cite and quicken this motion according to the exigence of the final, as when the In∣tervention

of any stops or Impediments of the motions of the Blood does Interveen, to o∣vercome which its necessarie that the efficient of the motion be bended to Superate these stops and gain tis end, then it must necessarly double its Force and Stroaks? Otherwayes every light Impediment or Obstacle which were equivalent to, and of equal moment, and Force with, the moderate and odinare career of the motion of the Blood would put a stop thereto: And indeed there is in a River something of a resemblance of this faculty, thô from an other kind of efficient, yet for the same or the like end; For any Impediments put to barr or dam up a River are soon overpoised by the swelling Force of the Water above them, till in proportion it overcome the strength of the stop: Now if it were otherwise, every Impediment equiva∣lent only to the present current of the River, either put by Accident, or Designe would interrupt their course, to the great hurt of Mankind, and the blemish of the Worlds fabrick.

Seing then the returnes of Reparation to the parts and functions ought to be made, both in time and quantity in proportion to the waste, by the efflux of the Arterial Blood from the Heart as the vehicle, and

thorow the arterys, as the conduites of these recruites; When this is done vegetlie, in∣tegrally, without any stop or delay, then redounds felicity, ease, and integrity, of the functions and life: But when that efflux is retarded or stopt, either by reason of the Blood it self, or some stopage in the ex∣tremities and small channels of the vessels; or by reason of immoderate and unusual waste beyond the proportion of the ordina∣ry supply, (as falls out in immoderate ex∣ercise and motion;) And, so I say, when by reason of any these causes, the heart cannot convey and lay in the desired sup∣pliment in due proportion and timeously, by stroaks repeated at the usual intervals, then it does, by precipitating the stroaks, and straiting the intervals of the pulsations, endeavour, what in it lyes, to overcome the slowness of the motion of the Blood, & to come so near as it can to the due and proportional distribution of nutriment▪ in respect of the wa••te: But if, notwithstan∣ding of these sedulous endeavours of the heart by the redoubling of the pulsations, that slowness of the Blood, shall by a gra∣dual encrease of the thickness, and of ob∣structions in the capillary vessels, prove yet so obstinare as still to be augmented, then

this leads straight to the porch and gate of Death; Death being nothing else but a to∣tal and permanent cessa••ion, and defect of this distribution.

If there remain yet any dif∣ficulty to comprehend this Scheme, because this incitation of the pulse, being only a natu∣ral action, and proper to the Animal part, thus circumstantiate, is made too like an effect of Reason, and savours too much the acting for an end, or of a vo∣luntary motion, to be applicable here: To answer this reasonable doubt, since it is very plain that Nature in the structure of the outward parts of Animals has acted so much Reason and Design, as importing clearly that the Idea of their end has regulate their fabrick; has also made the structure of all their parts terminate into such a perfecti∣on of the Animal, that the most rigide sur∣vey can find nothing wanting: As is most ingeniously displayed by the Honourable and Learned Boyle, in his Treatise of the Final Causes of natural things: Why should not the same Architect also have instructed the Function and inward parts with faculties to be exerted less or more, according to the particular exigence of the Animal: But

especially that radical and fundamental one of supplying all the rest with sufficient provi∣sion and nou••ishment; that it should be endued with a faculty to accelerate, when the n••urishment either by its fault or im∣moderate waste, is more then it ought, in its Returns, delayed: Otherwayes every light cause that did retard the accession of reparation or did waste it much beyond the ordinary recruite; would soon precipitate the Animal into inevitable ruine.

And also, seing most Animals are endued with swifness beyond their ordinary pace, whereby they flee dangers; why should they not be endued with the like inward faculty, to escape dangers internal that frequently threaten them. And indeed all these efforts which we call from Irritation giving a Re∣semblance of such a faculty as this, argue as much reason and acting for an end as this, that's here laid down does; For the Impression made in the place, being resent∣ed in the Brain the Fountain of Sense and motion; the Irritation or endeavour to be rid of the offending cause has its effects in the place first invaded or beset: and why should not the starving of the parts as much querelous as the surcharge of them is, be as well heard, and have also its releif; so far at their least, as motion can help them.

And there is yet a clearer resemblance of such a natural Action as this to be seen in the Pupil of the Eye, which without consent of the will Contracts and delates it self so much as is needful for the comodity of see∣ing, viz. Dilating where there is too little Light to let in more, and convey the Species into the Eye; and Contracting when there is too much Light, and letting in only so much Light, as is necessary to Paint the Species in the Eye.

And althô there is a Phaenomenon and case in Fevers which seems to oppugne this Hipo∣thesis, yet it is hoped that the same being duely considered, will rather confirm and clear it and the Cas•• is this, in some Fevers the Pulse is not altered as to the frequency or Vigour yet these portend great & imminent danger: which Phaenomenon or slowness of the Pulse comes from this, that althô the final Cause of its motion be here craving enough of the acceleration of the Pulse for reparation in proportion to the waste, yet it seems the efficient or Impellent of this motion or the first spring thereof that should answer ex∣actly the exegencies of the final; Is either stupified, attacqued, or befettered; and so there is no strugle or essay to overcome

the Impediments, and Supply proportion∣ably the waste: And as this case is of all Fe∣vers the most dangerous, commonly giv∣ing the name of malignant, so it brings the oeconomie, for the most part, soon to disso∣lution.

To unfold yet further this paradoxical Hypothesis, if any desire to know upon what nearest and immediate cause this slowness of the motion of the arterial blood, or delay of Reparation which excites the pulse to ac∣celeration does depend; unto this not imper∣tinent inquiry that an apposite answer may be made; it is to be adverted, that the blood is made up of innumerable little glo∣bules swiming in a limpide watery serum: As, being observed by Loewenhoek, with help of the microscop, is also delivered and describ∣ed by him: and as its very probable that these Globules do naturally require to be of such a bulk, figure and number, and the sero∣sity wherein these swim, doth also require to be of such tenuity and quantity, as may best facilitate the motion and course of the Blood throw the small channels and con∣duites betwixt the Arteries & veins: In which passage for the most part it depositates its nutritious parts, or particles: So it is very probable that slowness of the bloods mo∣tion,

to overcome which the heart excites frequent pulses, doth for the most part pro∣ceed either from the number or magnitude of these Globules augmented, or some vi••iation of their spherical figure, as their scabricity, and the like; Or further, thorow the visci∣dity of the serum into which as a vehicle they swim, and are carried: And thô from any of these alone this slowness of the blood may clearly proceed, yet it is certain that the ingemination and complication of these causes, rendring the groseness of the Blood more intense; may also render the slowness of its motion more contumacious.

To conclude then, as by this scheme here laid down, seemes indeed may be given pretty clearly, both a rational discovery, & a Mechanical solution of the nature & phenomena of Fevers; so it appears that former explications thereof, having raised so many fumy effer∣veseences, and turbid fermentations concerning them, could never yet bring the matter to a digested, pellucide, and defecat conclusion but having clouded the eyes with the mist of ••iry phantasmes, still left the mind boiling and working in the tumult of commotion, doubt and difficulty.

Notes

• The occasi∣on of these Errores dis∣covered.
• The Scheme of the New hypolsices of Fevers laid down.
• An obje∣ction against this Hypothe∣sis answered.
• Another de∣ficulty solved