The London practice of physick, or, The whole practical part of Physick contained in the works of Dr. Willis faithfully made English, and printed together for the publick good.

CHAP. II. Of the Motion and Effervescencies of the Blood.

WE must next enquire concerning the Bloods motion both natu∣ral (viz. by the help of what ferments; and by what fort of turgescency of the parts, it is circulated in a continual motion through the Vessels) and preternatural, viz. for what causes, and by the efforts of what parts, sometimes it boyles above measure in its Vessels, and falls into feverish Effervescencies.

Concerning the natural Motion of the Blood, we do not here en∣quire concerning its circulation: viz. by what knid of structure of the Heart and Vessels, as it were in a Water Engine, it is carried round in a constant course, but concerning its Fermentation, viz. by what kind of mixture of the Parts, and their mutual Action on each other (like Wine fermenting in a Vessel) it continually boyles: and this kind of motion depends both on the Heterogeneity of the parts of the Blood it self, and on the various ferments, which are inspir'd into the mass of Blood from the Viscera.

As to the first, those things which have altogether the like Particles, do not ferment, wherefore neither distill'd Waters, chymical Oyles, Spirits of Wine, or other simple Liquours are stir'd at all, but the Blood, consisting of various Elements of a contrary nature, and working on each other continually, ferments, and his all its Particles in a perpe∣tual Motion.

It is an Argument that Ferments are requir'd for Sanguification, because, when they fail by nature, they are supply'd by Art with good success: for fixt Salts, Alchalies, Extracts, Digestives, and especially Chalybeat Remedies give help only in this respect, that they re∣store

a new the ebullition of the Blood either weak or almost extinct.

As to what concerns natural Ferments, certainly many may be form'd and stor'd up in divers Parts, or Viscera: for any Humour in which the Particles of Salt, Sulphur, or Spirit, being very much exalted, are contain'd, indues the nature of a Ferment: After that manner Yest and Leaven come to be such, with which new Beer, and a mass of Bread are excellently fermented: In like manner, an acetous Humour in the Stomack, participating of an exalted Salt, helps there Concoction: and in the Spleen, the Dreggs of the Blood, by reason of the Salt and Earth exalted in them, turn to a ferment.

How great a Vigour comes to the Blood from the Womb and geni∣tal Parts, appears hence, because from the Privation or Discrasie of these in Virgins a Green-sickness, in Men a want of Beard, a weak Voice, and an amission of Virility follow, but the cheif ferment which ferves for Sanguification is lodged in the Heart; for here is the greatest scat of heat, in which the more crude Particles of the Chyme are kind∣led as it were, and acquire a volatility.

Therefore the Motion and heat in the Blood, depend chiefly on two things, viz. partly on its proper Crasis and Constitution, whereby be∣ing plentifully compos'd of the active Principles of Spirit, Salt, and Sul∣phur, it grows turgid of its own accord in its Vessels (as Wine in a Hogs-head) and partly on the ferment implanted in the Heart, which very much rarifles the Liquour, passing through its Sinus's, and forces it to spring forth with a frothy Effervescency.

Let thus much suffize concerning the natural Motion, Heat, and Fermentation of the Blood, in the even tenour of which the state of our Health consists: to speak now of its preternatural, or over great Effervescency, on which the Types, and Fits of Fevers depend. I call an over-great or preternatural Fermentation, when the Blood (like a Pot boyling over the Fire) boyles above measure, and being rarified with a frothy Turgescency, swells the Vessels, raises a quick Pulse, and, like a sulphureous Liquour taking fire, diffuses on all sides a burning heat.

This kind of Motion or Fermentation of the Blood is excellently il∣lustrated by the example of fermenting Wines: for Wines, besides the gentle and even fermentation, whereby they are first depurated, at certain times boyl so mightily, that they work over the Vessels: and if they are close stopt, they make them flye in pieces; after this manner, being put upon an effort as it were, unless they are presently drawn off from the Tartar, or their Lees into another vessel, they cease not to boyl, till the Spirit, being very much spent, and the Sulphur or Salt too much exalted, they either become over-fretted, or degenerate in∣to Vinegar.

Such an Effervescency is wont to be raised chiefly for two Causes; first, when any thing extraneous and immiscible is put into the Vessel:

(so some drops of Tallow or of Fat dropt into the vessel, produce this Motion) or secondly, when Wines having too much Lees or Tar∣tar (by reason of the sulphureous parts exalted above measure) fall into an Effervescence of their own accord, and boyl vehemently: for in whatsoever substance Sulphur abounds, and its Particles being loos∣ned from their mixture, joyn with one another, and are kept close together, there such immoderate Effervescencies are procur'd.

After the like (tho not wholly the same) manner as Wines fer∣ment, the Ebullition of the Blood is caused, viz. either some extrane∣ous and heterogeneous thing is mixt with the Blood, which, in regard it is not assimilated, is wont to cause a perturbation and Effervescence, till the heterogeneous thing be either subdued, or sent forth, and the confused and troubled Particles of the Blood, are clear'd again, and take to their former position and site in mixture. Or secondly, the Blood is troubled above measure, because some Principle or Element which composesit, (viz. the Spirit or Sulphur) is rais'd beyond the natural Temper, and becomes exorbitant, whereby the Particles of this, or that not agreeing with the rest, are loosned from their mixture, being loos'd make an effort more then they ought, exagitate the Li∣quour of the Blood, and cause an effervescence, which is not appeas'd, till the Blood, being inflam'd as it were, has burnt a long time with a feverish blast. But there is this difference betwixt these two boyl∣ings of the Blood, that the Effervescence which depends on the mix∣ture of an extraneous thing with the Blood, is for the most part short, or comming by Fits; which when the heterogeneous thing is separated or subdued, ceases of its own accord, and the troubled and disordered parts of the Blood readily return to their natural Site or Crasis: but the Ebullition which arises from the disordering of the exorbitant Spirit or Sulphur, is continual: to wit, here the whole mass of Blood is so open'd, and loosn'd from the strict bond of mixture, that taking a fire like an oily Lpquour, it does not cease to rage and flame till the Particles of the Spirit or Sulphur, or of the combustible matter are for the greatest part consum'd.

There remains yet a third preternatural way of effervescency, in which the Blood undergoes an alteration, which does not happen to Wine, but very frequently to Milk: viz. sometimes a coagulation of that liquor is induc'd by a morbifick cause, so that it substance is sus'd, and separates into parts, and there is a secretion made of that which is thick and earthy from the thin; by reason of which the Blood is not meetly circulated in the Vessels, but its congeal'd portions, being apt to be fix'd in the extreme Parts, or to stagnate in the Heart, interrupt its even motion, and greatly hinder it. For restoring of which, effervescencies greater than usual are rais'd in the Blood; to wit, such as every where occur in the Pleurisie, Plague, Small Pox, and malignant Diseases.