I Have read your Letter with all the Pleasure and Satisfaction imaginable, the Objections you have raised against my Hypothe­sis being the most solid and substantial I have ever yet met with: And you may assure your self that I have so great a Value and Esteem for Truth, that I would not dare to contend for any thing which is the Product of my shallow Understanding, that in the least stands in opposition to it. [Page 2]But as I would not by any means in the World oppose Truth, so at the same time I would not be guilty of so much Cowardice, as to quit its In­terest, because I meet with a multi­tude of Opposers. Altho your Ob­jections do carry the fairest shew along with them of any thing I have met with of this kind; yet I don't at all doubt, but very easily to clear my self from them, the which I shall endeavour to do with as much Can­dor and Friendship as you propose them.

Answer. As for my accusing Al­kalies as the Cause of all or most Dis­tempers, I must confess it was a very bold Undertaking, especially when by so doing, I opposed such Multi­tudes of Great and Learned Men, who by very strenuous and learned Argu­ments asserted the quite contrary; whom I could not suppose but that I should greatly displease, by dis­turbing them in the quiet possession of an Opinion that had long been em­braced by all sorts of people. I my [Page 4]self, as I elsewhere acknowledg, was formerly as great a Stickler for the Use of Alkalies in the Cure of Dis­eases, and did as little believe that they were the Causes of them, as any one of my hottest Opposers now doth. The Methods by which I came to change my Sentiments I shall here faithfully relate to you.

Whilst I was fairly jogging on in the ordinary Method of Practice, a certain Gentleman recommended to me a powerful Acid, which he told me I might rely upon in the Cure of some sorts of Fevers. When I con­sidered the thing as an Exalted Acid, I could scarce give the least Credit to what he said, tho at the same time I knew he had no design to impose upon me: however considering the fatal Success that frequently attended the Use of Alkalies and Alexipharmicks, (which however at that time I durst not attribute to the Medicines, but the [Page 5] Malignity of the Distempers) I was re­solved, upon the first poor Patient I had in a Fever, to try what the forementioned Acid would do; and after a Multitude of Trials, both upon Poor and Rich, I found I could by the means of my Acid cure most sorts of Fevers much more effectually and certainly than ever I before could by the means of Alkalies and Alexiphar­micks. The Effects of this Medicine, (which is a very cheap one, and known to every body) back'd with some other Observations, put me upon thinking that Fevers and other Distem­pers did not proceed from the Blood's abounding with Acid Particles, but on the contrary with Alkalious ones: for if it had abounded with Acids, the giving of more Acids must have aggra­vated the Symptoms, whereas on the contrary, I found by the means of my simple Acid (which however was communicated to me as the greatest [Page 6] Secret) I could take off the most dreadful Symptoms attending most Fe­vers with all the Ease imagina­ble. Upon which being greatly in love with Chymistry and Chymical Opera­tions; and having a convenient La­boratory, and all Necessaries at hand, I was resolved to examin the Blood of Persons in all Distempers as fast as I could conveniently procure it, to see what Substances abounded; and after a mul­titude of Experiments in most Cases, I could never find any reason to charge Acids in any one. And that I may not be defective in my Duty to so friendly and ingenious an Objector, I shall here trouble you with some of my first Experiments.

I could add a multitude of Experi­ments of this kind, but they belong­ing to another Piece, I have thought fit to trouble you with no more; and in relation to these few, I think it necessary to premise a few things, that I may make things as clear as may be.

To avoid the grand Objection, that by exposing things to violent Fires there are new Substances produced, which were not existent in the Concrete before, (which Objection I shall take occasion to make appear to be but a very trifling one) I took the follow­ing Method, as the only one by which I could most clearly satisfy my self, being the most plain and easy one imaginable.

I first of all put the Blood as it came out of the Veins, Serum, and all toge­ther, into a glass Retort with a very wide Mouth, to which I had a Receiver adapted as fit as possibly I could. I afterwards put my Retort into a sand Furnace, under which I made a very gentle Fire, which I increased by de­grees, till the Drops began to fall at a­bout a Second's distance one from ano­ther; in which state I continued it, till the Phlegm was all come over, and un­less in one or two very extraordinary [Page 20] Cases I have always found the Phlegm come over first, which perhaps to some may appear a Paradox, that what we commonly call Volatile Spirit and Salt should not rise before the Phlegm; but upon trial, I am sure whoever will give themselves so much trouble, will find it true. When it had dropt so long that one Drop being dropt upon two Drams of a strong Solution of Syrup of Violets would turn it green, I then changed my Receiver, and continued my Fire till nothing more would come over; and this last I call Spirit, having al­ways a proportion more or less of a fe­tid Oil mixt with it. Now what we call Spirit of this kind, is only a pro­portion of Volatile Alkalious Salt mixt with so much Phlegm as will well dis­solve it: Therefore I confess the most nice way of making these Experiments, is to separate the Volatile Alkalious Salt by it self, without any mixture of [Page 21] Phlegm; but every Experiment requi­ring a fresh Vessel, and the Vessels themselves being very chargable, it would be almost impossible for any private Man to make a sufficient num­ber of Experiments without the assist­ance of the Publick, which occasion­ed me in the Preface to my Tract of the Gout, to propose a Publick Stock to carry on this Work, to bring things to an absolute certainty, if possible.

However, altho these Experiments are not the most accurate that might be made, yet they are plain and easy, and are capable of being made by those who want the common Appara­tus for a Laboratory. An Iron Pot set up in the Corner of a Chimny, with a few Retorts and Receivers, are all that are necessary for the making of these Experiments; whereas for the other sort there are required long bolt- Heads, each of which will serve but for one Experiment, with nice Furnaces, and [Page 22]so much other charge and trouble, that few private Men are either ca­pable or willing to be at, to make such a number of Experiments that are requisite. But by the way I have set down, a Man may make a vast num­ber of Experiments for a small charge; it is but going by one Rule in the ma­king of them: and I don't see, but a Man may act with as much certain­ty as in the other, only I must con­fess it is more liable to the Objections of Cavillers; but for such I have no value, it being only for such candid ingenious Persons as your self, for whom I am willing to take pains.

Let a Man but nicely observe to change the Receiver, when one Drop will turn the Syrup of Violets green, and that Blood that affords the greatest quantity of such Spirit afterwards that abounds with such Particles, may rea­sonably be supposed, nay I think does certainly appear to abound most [Page 23]with Volatile Alkaly, or at least what by all Mankind is taken to be such, it answering all the Phaenomena that Spirit of Harts-horn and Salt Armoni­ack will do; affecting the Palat in the same manner, and making an Effervescence with all sorts of Acid Spirits, such as Spirit and Oil of Vi­triol, Sulphur, Sea-Salt, Nitre, Vine­gar, &c. Now if such a Substance as this be not to be called an Alkaly, I should be glad to be informed what is; but it is what I at present call so for want of a better Name: and that Blood that by this simple easy way of Distillation affords the greatest quan­tity of Spirit of equal Strength, I cannot forbear to charge with abound­ing with a greater quantity of Alkaly than that which affords less. And in examining the foregoing Experi­ments, it plainly appears that the Blood of People labouring under the Distem­pers there mentioned, doth afford a [Page 24]much greater quantity than that of the healthy Person; that of the Person in a Consumption affording the least of any of those in a morbid state, for which a very good reason may be given: the great quantity of luxuri­ant Alkaly being thrown upon the Lungs, which causeth the Ulceration there, and the discharge of such a quantity of Pus or Matter afterwards as emaciates the Body even to a Skele­ton.

As for the Fire's producing new Substances, which were not existent in Bodies before, or which is more pertinent to the point in hand, ma­king Acids Alkalies or Alkalies Acids, or producing Alkalies or Acids from Bodies in which they did not exist before, I think there is not the least weight in it: I am sure it is contrary to my Ex­perience, and I believe to the Experi­ence of all inquisitive Chymists that have ever gone before me; tho I [Page 25]confess there have been some super­ficial ones that have dreamt such things; but to the best of my ap­prehension, without the least reason for so doing. I never could find, but manage Vitriol in what manner, or with what degree of Fire you please, and it will always produce an Acid Spirit; do the same by Harts­horn, Blood, &c. and it will always produce an Alkalious one, or at least what we call so: for if people will cavil about Words, we shall never have an end of Controversies; and in­deed most of the great Controversies we have had in the World have been more about Words than Things; Men have contended more earnestly for the Shadow than the Substance. But my present Controversy with my Wor­thy Brethren is not such; our Differ­ence is whether Diseases proceed from the Blood's abounding with Alkalious or Acid Substances, things which dif­fer [Page 26]much more than in Name, their Natures being directly opposite one to the other. I confess there are some who have complained both of me and others that have written concern­ing Alkaly and Acid, that we have not sufficiently explained our selves what we mean by those Names: This I take to be a Dispute about Words only, since there are few People in this day, who upon the first view of any of those things of either Tribe, especial­ly of the manifest ones, cannot rea­dily give their Judgments to which they belong, and this even amongst those who are not Physicians: and therefore altho we may not be able perhaps to give an exact Definition of the Words; yet since by these Words all people know we mean such and such Substances whose Natures are directly contrary, that ought to breed no difference. And for my part, I know no other use of Words, than [Page 27]by the means of them to impart my Mind to others; and if that Intenti­on be once answered, I care for no more, but shall leave the Philologists to squabble as long as they please. But as for the producing either Alkalies or Acids by the means of Fire out of those Bodies in which they did not exist before, or the changing of an Acid into an Alkaly, or producing ei­ther out of the other that was simply one of them before; if any one will shew me such an Experiment, or de­monstrate such a thing without Fallacy, I shall own my self his humble Ser­vant.

As for the Inferences I draw from the Serum of the Blood turning a So­lution of Syrup of Violets from a blue Colour to that of Greenness, being what all manifest Alkalies will do, all manifest Acids changing the same blue Colour into Redness; I see no reason at all that I have to recede [Page 28]from what I have said concerning that matter: For if it be true that all manifest Acids do change a Soluti­on of Syrup of Violets from a blue Colour to that of Redness, and all manifest Alkalies do change the said blue Colour into a green one; if the Serum of the Blood doth so change the Colour, a Man may, to the best of my Apprehension, without Pre­sumption conclude, that that Serum which doth change a Solution of Sy­rup of Violets from blue to green, doth abound with Alkalious Particles: And I am sure if it did abound with Acids, it would not fail of changing the blue Colour of the said Solution into a red one: Which is a thing any Man may easily try; let but a suffici­ent quantity of any Acid Spirit be mixed with the Serum of a sick Man's Blood that will before in a small quan­tity turn a very large quantity of Solution of Syrup of Violets from [Page 29]blue to Greenness; if the Acid be so much as will overpower the Alkaly in the Serum, instead of turning a Solution of Syrup of Violets green, it will immediately upon the mixing of it become red.

But that you may see I am not the only Person who has made use of this Experiment to distinguish be­tween Alkalies and Acids, I shall pro­duce an Authority or two for my so doing. Dr. Fran. Andre of Caen, in his Discourse concerning Acid and Alka­ly, pag. the 65th, English Translation, tells us, That the principal Cause of permanent Colours comes only from the different nature and different mix­ture of Acid Salts with Alkaly Salts, which we may observe by divers Ex­periments.

But my Hypothesis doth not altoge­ther hang upon so slender a Thred as the change of Colour, tho that be [Page 31]a better Foundation than a great ma­ny Hypotheses are built upon. You may very well remember that I brought this Experiment upon the Stage, only to satisfy Gentlemen who have not the conveniency of making more elaborate ones: And all Man­kind having imbibed the Notion that if any thing ailed them, they imme­diately concluded that it proceeded from an Acidity of their Blood; I there­fore thought it my Duty to convince them of the contrary in the most fa­miliar manner I could; but I never expected that Physicians should take up with it, I referring them to a more certain Method, viz. to analize the Blood of their sick Patients, and to compare the Substances produced from it, with the Substances produ­ced from the Blood of People in a state of Health: And if once they will but take that Method, I am morally certain that the number of [Page 32]my Enemies will every day decrease. But let People continue to say what they will of me, I shall endeavour to satisfy my self, and to act for my Patients with as clear a Conscience as possibly I can: And if after all I am reproached by my Brethren, I must bear it as well as I can. It ne­ver will be in any Physician's power to make people Immortal; but at the same time I am absolutely certain that peoples Lives are frequently pro­longed by the use of proper Re­medies; and I doubt not but that they are also shortned by the use of im­proper ones: And if we are mistaken as to the Cause of Diseases, I don't see how we can readily find out proper Medicines.

Answer. I confess this is close argu­ing, and much to the purpose: But you may remember that I no where say that the Serum of well Persons Blood will not turn a Solution of Sy­rup of Violets from a blue Colour to that of Greenness. But on the other hand, I have asserted that the Blood of those labouring under any Dis­temper I have met with will do it, in order to prove that the said Distempers did not proceed from Acids; because if it had abounded with Acids, in­stead of turning it from blue to [Page 34]green, it would, as is before obser­ved, have turned it from blue to red. Well, but still the Serum of the Blood of a well Person will cause the same change in the Solution of Syrup of Violets as that of a sick one; and therefore to rid my self of that Diffi­culty is the great thing I have now to do.

First, I all along throughout my Tract of the Gout, the Piece you re­fer to, and elsewhere, do endeavour to prove that the Blood of Persons in a morbid state doth more abound with Alkalious Particles than that of well Persons, but no where say that the Blood of well Persons hath no Al­kaly in it: And that the Blood of sick People in all or most Distempers doth abound with such Particles more than that of those that are in a state of Health, is to be demonstrated several Ways: First, If you take an equal Proportion of the Serum of the Blood [Page 35]of a healthy Person, and of that of a Person in a Fever, Pleurisy, &c. and pour them into the same Quantities of Solution of Syrup of Violets of equal Strength, you will find that where­in the Serum of the sick Person's Blood was poured, to be much greener than the other. Secondly, If you take two Ounces of the Blood of a heal­thy Person as it comes out of the Veins, Serum, and all together, and two Ounces of the Blood of a Person in a Fever, Pleurisy, a Fit of the Gout, &c. and commit them to Distillation in the same degree of Heat, you will find that the Blood of the sick Person will produce a much greater quantity of Alkaly than that of the Person in a state of Health.

Secondly, What shall I do with this Alkaly that is to be found in the Blood of healthy Persons? Because e­very Body has some Alkaly in their Blood, must every Body therefore [Page 36]labour under some Distemper? Why truly I can't say that I ever yet met with that Person, who upon strict En­quiry had not some Complaint or other to make. Mankind since the Fall is subject to Death every moment; there being since that time a Principle of Death, in opposition to that of Life, implanted in our Natures; and not only in our Natures, but in the Natures of every thing else for our sakes: And God said to Adam (upon his Fall) Cursed be the Ground for thy sake, &c. I confess there are many in our Age, who will laugh at and ridicule me for having recourse to Sacred Writ, e­specially to the Writings of Moses, which they look upon as a kind of Romance; but let them laugh on. If there were not a Principle of Death within us, how is it possible for a Man one Hour to be in a good state of Health, and the very next to be ex­piring? How this may be I shall en­deavour [Page 37]to demonstrate as clearly as possibly I can.

All the Alkaly that there is to be found in the Blood is most certainly an Excrement, and in a way of being carried off by some of the Emunctories; and if any of the Emunctories chance to be stopt, that this excrementitious Alkaly hath not room to pass out by them, why then there is a Distemper of some kind or other caused, the Blood being overcharged with this ex­crementitious Matter. How many Distempers are occasioned by what we call taking of Cold, which is nothing else but a Constipation of the Pores? What is the Occasion of the Jaundice, but an Obstruction of those Vessels in the Liver, which separate the bilious Particles from the Blood? and what dreadful Distempers does the Jaundice fre­quently cause? How are Mortals tor­mented by the Stone in the Kidneys and Bladder? and what is the origi­nal [Page 38] Cause of them, but an Obstruction in the Kidneys, whereby the excremen­titious Alkaly, which should be carried off that way, by its over long stay in those Parts is converted into that Substance we call a Stone? And who­ever will give themselves the trouble of distilling Stones either from the Kidneys or Bladder, will find that they are composed of Alkalious Particles. I could expatiate, and I doubt not give an Account of the Cause of all or most of the Distempers attending Human Bodies, from the excrementitious Alkaly being hindred from being car­ried off by the proper Emunctories. And I appeal to all Candid Ingenious Persons, even those who are my greatest Enemies, whether all the Ex­crements of our Bodies are not Alkalies. When I speak of Excrements, I don't mean that which is carried off by Stool, I having told you in another Place, that my squeamish Stomach would ne­ver [Page 39]yet give me leave to make Experi­ments upon that, to know what Parts it contained, but every Body knows that the Bile is the greatest part, if not all of it, carried off that way; and that the Bile is an Alkaly I suppose no Body doubts.

I know there are a great many who will reply, That we will allow you that the Matter, or at least the Saline Substance that is discharged by the Glands of the Skin, by Urine, the Bile, Tears, &c. are Alkalious; but there is another Excrement, the which you take no notice of, which is a very considerable one, and that is the Matter discharged from the Glands of the Mouth, called Spittle, which in all respects seems to be an Acid. To which I answer,

That the Saliva or Spittle is so far from being an Excrement, that it is one of the most noble Juices that our Body affords; it being the only [Page 40] Menstruum that Nature hath furnished us with for the dissolving of the solid Food we eat, and turning it into a nutritious Juice: For by chewing of our Meat we compress the Salival Glands, and cause them to throw out a sufficient quantity of the Juice con­tained in them; which being mixed with the Food, is along with it carri­ed into the Stomach, where the Office of Digestion is performed. But those People, who swallow their Meat with­out chewing, seldom or never digest it, and are always lean. Now when I speak of Saliva or Spittle, I don't mean that inviscated, coagulated Sub­stance that People hauk up in a Morn­ing, or discharge when they have a Cold as they call it, that being a dege­nerate Saliva; but I mean that thin, Limpid Substance that some great To­bacco-Takers lavishly let run from them: which is the only reason that the smoaking of Tobacco takes away [Page 41]most Mens Appetites; for would they smoak Tobacco as a great and worthy Prelate and my self do, and as all the Turkish Nation do, which is to swal­low their Spittle, they would rarely want an Appetite.

But that I may return to my pro­per Business, which is to prove that all the Alkaly we have in our Blood is an Excrement, and in a way of being carried off as such, or for want of being carried off, would cause a Dis­temper of some kind or other. And here give me leave to acquaint you, that according to the best of my Ap­prehension, the Matter of all our Dis­tempers is the same; but according to the difference of the Part immediately affected, the Distemper differs: And indeed when I consider the wonder­ful Structure of our Bodies, of what Multitudes of minute Parts it is compo­sed, instead of being surprized at our being sick and out of order so [Page 42]often as we are, I am almost amazed to think we are ever well. All Al­kalies that I know of will presently cause Rottenness and Putrefaction in Animal Substances, as may be seen in making of Glovers Leather, an In­stance of which I have given in my Tract of the Gout, from a very good hand. Nay it is a thing very easily to be experimented by any one, for let but a Piece of Flesh of any kind be put into a Liquor well impregna­ted with Alkaly, and in a small time (tho in the Winter, when things are not subject to putrefy) it will turn to a meer Putrilago, a Mass of Rotten­ness and Corruption. Whereas let a Piece of the same Flesh be put into Liquor impregnated equally strong with any Acid, and it will preserve it from Putrefaction. Alkalies, whether Volatile or fixt, being applied to the Skin, will either cause a Mortification, or destroy the Tone of the Part; [Page 43]whereas Acids of equal Strength will prevent Mortifications, where they are actually beginning, and frequently restore the Parts to their Tone, where it is lost.

But it may very reasonably be askt, where is the Acid in the Blood that does us all that Service you speak of, or what becomes of all the Acid we take in, you owning Bread to be an Acid, and several other things that are e­very day used by all Mankind, when in your Analysis of the Blood you men­tion no such thing, and seem to in­timate, that altho People take them in never so great quantities, yet they never abound so as to cause a Distem­per? This is what may reasonably be offered, and is very necessary that I should clear as well as I can.

The Life of Man I take to be a Fire or Flame, and all we eat and drink, [Page 44]together with the Air we draw in, to be as Fuel for this Flame; and that which is not proper Fuel for it is cast off as Excrement. Now I appeal to all Mankind conversant in Chymistry, whe­ther the Excrements of Fire, or of the Fuel of which it is made, viz. Ashes and Soot, be not Alkalies; and that our Lives are nothing else but a Flame or Fire of the same Nature with that commonly used, or very analogous to it, I think is plain.

It is the Nature of all common Fire to consume whatever is a proper Pa­bulum or Fuel for it, and to leave its Excrements behind it, which, as is before observed, are Ashes and Soot; in the Ashes is contained a fixt Alkaly, and in the Soot a Volatile one. It is very plain that the Body of Man would soon be consumed, unless sup­plied with proper Food; and how could this be, unless there were some­thing to consume it?

Common Fire cannot subsist where there is not a due Access of Air to it: Is it not the very same thing with the Life of Man? let him be but inclosed in a Place where the Air is not capable of coming at him, and immediately he expires. It is well known that it is the common Practice of Miners, and those who have occasion to go into subterraneous Vaults or Passages, to carry Candles, Torches, or some such things along with them, not more for the conve­niency of the Light they afford them in such dark Places, than for the Se­curity they are to them against the most imminent Danger, viz. the Loss of their Lives: for as soon as they once perceive their Lights begin to grow dim, common Prudence and Experience teaches them to retreat; and whoever has chanced to be so fool-hardy as to advance after the Light hath been extinguished, has [Page 46]scarce ever returned either to repent, or give an account of his Folly. A fatal Accident of this kind happened to two Men in a great Vault in a Yard belonging to my Father's House, into which Vault, if we put a large Pan of Charcoal well lighted, they would be extinguished in a moment; and the two Men before mentioned, as near as we could guess, lost their Lives in as small a time.

Heat and Warmth are the constant Concomitants of Fire: And that there is both Heat and Warmth in the Body of Man, none that is Master of his Senses will deny: But why should I make a Distinction between Heat and Warmth, when they only differ in degree? But not to stand any longer about that matter: How is it possible for the Heat of our Bodies to be sustained, unless there were a Fire within us to do it? We are generally as hot, if not hotter in Bed, altho we use no [Page 47] Exercise to excite the Motion of our Blood and Juices, than when we are up and in motion. Nay, mere Motion, let the great Des Cartes and his Follow­ers say what they will, will never cause any Heat in fluid Bodies, altho excited never so much: I confess in solid ones, upon violent Friction or the like, there will a Heat arise; but what relation hath that to us, when we are asleep?

There is a received Maxim, that there is no Smoak but there is some Fire: Every Body must be sensi­ble what vast quantities of Steams there are continually discharged from all Parts of our Bodies; and how that comes to be, unless occasioned from some Fire within us, I cannot under­stand.

I confess I have the Concurrence of some of the greatest Men perhaps the World hath afforded, that the Life of Man is a Flame; but at present I have [Page 48]not leisure to peruse their Writings to see what they have said upon this Subject.

If any Man shall ask me, how this Flame came to be first kindled? I shall make no other reply, but desire him to inform me how the Ovum came to be impregnated with the Masculine Seed, so as to make it capable of pro­ducing a Human Body? and when he hath done that, I will quickly tell him how this Flame came to be first kindled.

The next thing I have to do, is to confider what is the proper Pabulum or Fuel for Fire, and this every body knows must be something that is sul­phureous: Now there is scarce a Sul­phur we know of that is not com­bined with an Acid; Sulphurs seeming to be the genuine Vehicles for Acids, with which they are generally united, few Sulphurs being devoid of Acids, and few Acids devoid of Sulphurs; [Page 49]and as the one or the other predomi­nates, so they are denominated either Acido-Sulphurea or Sulphureo-Acida. As Sulphurs are the Vehicles of Acids, so Acids seem to be a sort of Vinculum to Sulphurs, by the means of which they are hindred from Dissipation. Whenever a Sulphur is devoid of Acid, it is of so Volatile a Nature, that it is scarcely to be preserved from Dis­sipation: Not that I suppose any Sul­phurs to be perfectly destitute of an Acid; but the less Acid they have mixt with them, the more Volatile they are; such are Rectified Spirit of Wine, Camphire, &c. And Mr. Godfry assures me that he can make Spirit of Wine so Volatile, that a Drop of it won't fall to the Ground, but disap­pear almost as soon as it is disingaged from the Mouth of the Bottle in which it is contained. Now the purer the Pabulum is, the less Excrement is pro­duced; Spirit of Wine and Camphire [Page 50]produce little or no Excrement at all; whereas Oil Olive, Bees-Wax, Tallow, &c. afford a great deal of Soot, in which is contained the Volatile Alkaly. Most Vegetables commonly in use for burning, afford a great quantity both of Ashes and Soot, some more of one, and less of the other; as Oak a great quantity of Ashes in which is con­tained the fixt Alkaly, and but a little Soot, in which the Volatile Salt is con­tained. Beech on the other hand pro­duces but a small quantity of Ashes, but a large quantity of Soot: this is what I have been informed of by those who burn quantities of Wood. The Substances we live upon, and are nou­rished with, are not to be reckoned amongst the number of those which afford no Excrement upon burning: and by the way I can't understand what should become of all we eat and drink, unless, as is before obser­ved, there were a Fire or Flame with­in [Page 51]us to consume it; and the Consump­tion is so great, that we are not able to live without a constant and fre­quent Supply. And which to me is none of the least Arguments to prove that our Life is a Flame, is what is manifest by every day's Experience, viz. Let a very fat Man be seized with a Fever, or any such Distemper, at­tended with a total loss of Appetite; and the Fat, which is the proper Fuel for Fire, will first be consumed: and in such Distempers it is frequently seen that very corpulent Persons will in a small time be wasted to a Skeleton; when at the same time the sensible Evacuations of Urine and Stool are less than in a time of Health; which thing could not be, unless there were a Flame to cause that Consumption: And wherever there is a Fire or Flame, especially when supplied with gross Matter, there must be a throwing off of Excrements; which is the reason [Page 52]that the Blood in Fevers, and other Dis­tempers of that nature, abounds more with Volatile Alkaly than that of well People, because the Flame is more excited at that time, and the secretory Vessels designed for that purpose being some way or other obstructed, can­not carry off the Excrements so fast as they are produced.

Let us consider what all the Alkali­ous Salts, whether Volatile or fixt, are. I suppose no one can produce me a fixt Alkaly, which is the bare Product of Nature: The very Name it self being derived from the Salt of the Ashes of the Herb Kaly, as I have ob­served in the Appendix to my Essay of Alkaly and Acid, in concurrence with several Authors, who have written up­on the same Subject; tho none that I know of have ever written upon it with the same design that I have done. But that you may see I am not singular, I shall produce two or [Page 53]three Authorities. Swalve in his Trea­tise of Alkaly and Acid, pag. 48. does thus define it. Originem Nominis Alka­li ab incineratâ Herbâ AEgyptiacâ Kali de­sumptam haud ignoras: Salibus illud fixis & lixivialibus abhinc applicatum; illud (que) primariò judicatum Alkali, quod Gensin suam è cinere & lixivio traxerat. Ta­chenius in his Hippocrates Chymicus de­fines it much after the same manner. Fit ita (que) Sal Kali ex Herbâ Kali, magna copia in Aegypto proveniente, quae ibidem vi­ridis exuritur, & ad nos transfertur; à quibusdam vocatur etiam Soda, Alumen cat­mum, & vero nomine Sal Kali appellatur; non reperitur tamen Sal Kali in Natura, nec in omnibus tribus Regnis, nisi ab Artifice ignis ope producatur. For my own part, I could never yet see any such thing as a fixt Alkaly to be obtained any other way than from the Ashes of Plants, which are that part of them that is altogether unfit for Fuel for common Fire, they plainly appearing to me to [Page 54]be an Excrement, and as such will rot and destroy all Bodies, especially Ani­mal ones, that they are mixt with. In Animal Bodies there is no such thing to be found unless in the Bile, which is an Excrement, and seems to be as genu­ine an Excrement of Fire as any thing whatsoever, both from its burne Tast, Colour, &c. and I am sure if it be detained in the Body, will play the Devil.

As for Volatile Alkalies, they are to be found in Soot, in Plants after Pu­trefaction, in Urine, in Horns and Hoofs of Animals, and in Blood; and altho Sweat abound with a great quantity of it, yet that is not to be obtained in quantities sufficient to draw Volatile Salt from it. Soot is the Volatile Excrement of Fire, or of the Matter of which Fire is made. Urine is an Excrement of our Bodies, and the Volatile Salt in it the Excrement of Animal Fire, or of that which is its [Page 55] Pabulum or Fuel. The Horns and Hoofs of Beasts are generally allowed to be excrementitious Parts of their Bodies, and they afford the greatest quantity of Volatile Salt of any thing besides. As for Blood, the Volatile Alkaly to be obtained from it, is on­ly the excrementitious part of it, or rather of the vital Flame, or the Pabulum of it, in a way of being carried off by some of the Emunctories, which, if it chance to be obstructed in its Passage, affects the Body with some Distemper or other. As for the Vola­tile Salt to be obtained from Plants after Putrefaction, I shall give you a particular account of it, by reason that some Men have made a great stir about it, and spent a great deal of time in quest after it, supposing it to be one of the grand Medicines of Na­ture. Most, if not all Vegetables do principally consist of a Volatile Acid and a Sulphur, which make them a [Page 56]proper Fuel for Fire: Now let any of the Aromatick Plants, such as Rose­mary, Sage, Lavender, Mint, &c. be well dried, and afterwards be put into a Hole in a moist Cellar, and rammed down very hard; let them lie without a Cover till they grow hot; after they have done so some time, and the Acido-sulphureous parts are exha­led (which is much the same, as if they had been burnt) they will then contract a stinking ill Smell; when they are in this state, put them into a tall glass Bottle, with a glass Head, and in gentle Heat of Sand you will ob­tain a Volatile Alkalious Spirit and Salt, good for nothing else that I know of, but to bring other Bodies into the same state of Corruption that the Plants from which it was extracted were before it was drawn from them. Thus I have let you see what is my Judgment concerning Alkalies, and how they are produced.

But as for the Acid that we take in as Food and otherwise, that, together with the Sulphur, are made use of as a Pabulum or Fuel for the vital Flame; and were not the sulphureous Particles in some measure suppressed and de­tained by the means of an Acid, the Thred of our Lives would be but ve­ry short. Dr. Andre of Caen in Nor­mandy in his Discourse of Alkaly and Acid; speaking of Acid, pag. 21. Engl. Translation, he saith, There is no­thing in this World which owes not its birth to an Acid Salt: Nothing can live nor be multiplied without it: It is that Soul of the World, of which the Antients have so often told us. Tachenius in his Clavis Hippocratis Medicinae, from pag. 3, to pag. 11. gives strange Encomiums of it, some of which I shall here tran­scribe. Speaking of Acid, he brings in Lullius. Nos & multi alii, inquit, vocamus illum Filium Solis: nam primò per Solis influentiam fuit generatus per [Page 58]naturam sine adjutorio scientiae vel artis; & ideò Aristoteles vocavit Solem patrem & Terram matrem omnium vegetabilium, &c. He afterwards says, Acidum ita (que) est & pingue antiquissimum principium, & omnium rerum vita & fons, quod variis nominibus nominarunt Scriptores, ut ignem, solem, aurum, spiritum, sul­phur, forma, & sexcentis aliis nomini­bus, quae omnia synonima sunt, est (que) ea­dem res, cui tamen diverso respectu diversa nomina imponuntur; nobis tamen eam hic & ubique commodiore opportunitate Acidum vocare libet. Again, A Sole i­ta (que) ut a fonte defluunt Acidum naturale & lumen vitale, quae reipsa sunt idem, sed officio distinguuntur: Acidi enim mu­nus est ad interiora Naturae penetrare; lu­minis verò exteriora patefacere, utcum (que) solis radii operentur; adeo (que) Sol est pri­mum naturale organum, cujus accessu & recessu omnes naturae operationes variae reguntur, intenduntur ac remittuntur. Hinc Cosmopolita ingeniosissimus; si non [Page 59]esset vis vegetabilis sulphuris (id est Aci­dum pingue & filius solis) non coagula­retur aqua in herbas: si ita (que) Acidum à sole fluens infunditur in materiam ex gr. mineralem statim recipit determinationem naturae, & virtutis mineralis, & sic de cae­teris animalibus, & de Vegetabilibus rebus dixit Luilius; & proptereà quòd haec aci­ditas naturalis omnibus mundi Materiis co­pulatur, Mercurii nomen à sapientibus adepta est: Et licet oculus vulgi quotidie videat Acidi naturalis multiplicationem, nec non in­corporationem, attamen illud non cognoscit: exempli loco sit minera salis petrae Patavii jam evacuata, quae quinque vel septem anno­rum decursu rursus repletur, est enim terra ejus nutrix, Hermete teste, unde hic spi­ritus in illa corpus assumit, at (que) fit inflam­mabile nitrum.

Acids are without doubt the most perfect Bodies in Nature, since they can­not undergo a Putrefaction; and what we take in by our Mouths is so far from being too much for us, that be­sides [Page 60]it we are not able to live with­out drawing in fresh Supplies from the Air every moment; and that the Air is filled with Acid Salts, a Multi­tude of common and obvious Expe­riments do evince: as for instance, Let Vitriol be distilled with the most violent Fire imaginable, so that it will not yield the least drop of Acid Spirit more; do but take out the Caput mortuum or Colcathar, and expose it to the open Air under a Shed, where it may not be rained upon, and in a few months time it will become good Vitriol a­gain, and yield as much Acid Spirit as it did at first time, and this it will do ad infinitum: The same thing may be done by the Caput mortuum of Sea­salt, Nitre, &c. Now if the Air did not abound with Acid Particles, from whence came those insipid Bodies that were totally deprived of the A­cid they had in them by the first Dis­tillation, [Page 61]to regain the same quantity of Acid that they had before they were distilled? If you expose the Caput mortuum of those things that by Dis­tillation had afforded an Alkalious Spirit or Salt, that Caput mortuum will never regain its Alkaly again, let it lie never so long; which argues plainly that the Particles of the Air are not Alkalious: And therefore were Acids so injurious to Mens Bodies as some would have us believe they are, every Draught of Air we take in must poi­son us, since the Air is full of Acid Particles; and I believe no body doubts but that the Air has a free Com­munication with the Blood, if not by the Lungs, at least by the receptory Pores of Skin: But I think it's plain that there is a Communication with it both ways.

By all the ways I could yet con­trive, I have not been able to pro­cure one Grain of pure Acid from the Blood of either healthy or sick People: [Page 62]But in the before recited Experiments you find there is always a proportion of fetid Oil, with which Oil the Acid is imbodied to make it a proper Pa­bulum for the vital Flame; and when once Acid and Oleaginous Bodies are well united, which they will very readily do, it is no very easy matter to cause a Separation of them. Now the reason that this Oil hath such a very ill Savour is from its coming o­ver the Helm along with the Volatile Alkaly; all Alkalies, whether Volatile or fixt, giving a very ill Smell to sul­phureous oleaginous Bodies, especially if together they are exposed to a great degree of Heat; and the Heat that is required to bring them over the Helm is much greater than that of our Bodies, tho in a burning Fever: Yet from the Action of the Volatile excrementitious Alkaly upon the sulphure­ous parts of the Blood, may I think a very good reason be given for the [Page 63] Symptoms that attend most, if not all Fevers; for all Alkalies destroy Sulphurs, as may be seen in the making of Soap, Hepar Sulphuris, &c. Sulphurs are the active Principle in both Ani­mal and Vegetable Juices; Alkalies by breaking and dividing the Particles of the Sulphurs excite Fermentations, and by degrees cause a total Dissipa­tion of them. Acids are a sort of Vin­culum to Sulphurs, and therefore they suppress Fermentations, and keep the Sulphur from Dissipation: From whence I infer that a true Oleosum must be the great Medicine; but it must not be such a one as commonly goes under that Name, which is only a Combination of Volatile Alkaly with Spirit of Wine and Aromatick Oils or Spices, instead of which it must be an Acido-oleosum, an exalted Acid, com­bined after the foresaid manner: The Life of Man it self being principally supported by an Acido-oleosum.

If any one asks me what I mean by Sulphur? My Answer is, whatso­ever is inflammable. And with such kind of Substances the World is almost every where filled: For with­out them neither the Lives of Men nor Beasts could be any way supported; and therefore those places that are best supplied with them, are best stockt with Animals of all kinds; whereas those that are deficient in them, such as the Desarts of Arabia, &c. are al­most wholly destitute of all kinds of living Creatures.

Answer. I own it is one of the genu­ine and constant Effects of an Alkaly to cause an Effervescency, when mixt with Spirit of Vitriol or any other Acid Spirit; but whether this Effer­vescency be to be accounted a Fermen­tation, I greatly question: Tho Alka­lies will excite Fermentation in fer­mentible Liquors, as is well known to many Mechanicks, and I fear too well by the Brewers about this City. As for what you mean by the green Se­rum, which you say will not ferment or effervesce with Spirit of Vitriol, I cannot tell: But sure I am, that if you put a little Spirit or Oil of Vitriol into a small Bottle, and upon that pour some Serum of Blood that will turn Syrup of Violets green, it will immediately become intensly hot, and a great many Bubbles will im­mediately rise, which looks very like a Fermentation, if it be not one: [Page 67]therefore when you made this Experi­ment, upon which you are so confi­dent, there must needs be some Error committed; for upon your urging this thing, the first Opportunity I had I made the Experiment afresh, and it succeeded the very first time; and I doubt not, but if you will give your self the trouble of making this Experiment again, it will not fail of succeeding.

As for those warm Particles that you say are often predominant in the Blood, I must confess I don't under­stand what you mean by them; the Blood, whilst we are in a state of Health, is always warm, the reason of which I have before given you. If we have a Fever upon us, the Blood exceeds its natural Temper, ac­cording as the Fever is more or less violent: Now the Cause of this Ex­cess of Heat in a febrile state I take to be as follows; in most Fevers, e­specially [Page 68]in the beginning of them, there is a Constipation of some of the Emunctories; so that the excrementitious Alkaly, which should be carried off by them, is detained in the Blood, which by breaking of its Globules, and dividing of the sulphureous Particles, which are the Pabulum of the vital Flame, does either excite what we call a Fermentation, or rather by divi­ding the sulphureous Particles, and subduing the Acid that held them to­gether, does increase the Flame to an intense degree. An Instance of which we have in common Fire, as I have elsewhere taken notice of, and shall here again repeat, viz. let the Matter of which Fire is made be laid close together, and then kindled, and it will consume leisurely and by de­grees; whereas let it be laid at some little distances one from another, and it will consume with a rapid and in­tense Flame. Salt-Peter also and [Page 69] Brimstone being mixt together, will burn with a gentle and easy Flame; but by adding a Proportion of Char­coal-Dust (as is the Method in making Gun-powder) wherein is contain'd the fixt Alkaly of the Wood, the said Alkaly by causing a Division of the Particles of the Nitre and Sulphur, does so alter the Property of it, that in­stead of burning placidly and easily, the least Spark of Fire falling into it, will cause an Explosion, viz. make it take Fire all at once, and so be con­sumed as 'twere in an instant. Are not the Attacques of some Fevers and other acute Distempers much like to this Explosion, wherein Nature seems to be overthrown, and the whole Course of it put out of order almost in an instant? This is all at present I think necessary to take notice of in relation to the warm Particles you speak of; and that Acids are the only Medicines to suppress this unnatural [Page 70] Heat, I think I have already made ap­pear. As for the Inferences you are pleased to draw from them, I think I have nothing more to do with them, but slightly to touch at them, they having already fallen under my Con­sideration. And I have sufficiently demonstrated that Alkalies are the Causes of all preternatural Heats in our Bodies.

But supposing that preternatural Heats are occasioned by the supera­bundance of Alkalies in the Blood, you still seem to be dissatisfied about them also: For, say you, if they are fixt ones, how comes it to pass that on the Dissolution of the Texture of the Blood, they claim the highest Place, and nothing will serve their turn, but they must needs swim in the Serum? if Volatile, how is it that we often-times find this warm Serum little better than insipid? Volatile Salts you know are aculeated, and affect [Page 71]the Palat strongly. May they not rather be of a sulphureous Nature, since 'tis the Nature of such Substan­ces to sit uppermost on the Dissolu­tion of Bodies?

First, I don't remember that I have any where said that fixt Alkalies do claim the highest Place in the Dis­solution of Bodies, and that they swim uppermost in the Liquors, in which they are dissolved: But this I believe you infer from my Experiment with the Serum, which is the lightest part of the Blood, and therefore is upper­most in the Poringer, after it hath stood some time, and that a Separa­tion is made in the Parts thereof. Now I did not make use of the Ex­periment with the Serum and Syrup of Violets, thereby to intimate that Se­rum only was over impregnated with Alkalious Particles; but that being the most colourless part of the Blood, was therefore most proper for [Page 72]such an Experiment: For should I have made such an Experiment with the fibrous and globulous Parts of the Blood, which are combined together in one Mass, they are so imbued with a scarlet Dye, that a small quantity of it would tinge a great quantity of Solution of Syrup of Violets with the same Colour, altho at the same time it were greatly overcharged with Alkalious Particles. Therefore in my plain and easy way of anali­zing the Blood, I have made use of it altogether, as it came out of the Veins. But if a Man considers with what Rapidity the Blood moves along the Vessels, it is impossible but all the Parts must be so mixt together, that if the Serum be overcharged with Al­kalious Particles, the other parts must be so also; or if the other parts be overcharged, the Serum must be in like manner so. But however, as for sixt Alkalies, the Blood is very rare­ly [Page 73]overcharged with them, the Sub­stances we take in for our Nourishment affording very little of them after burning; and therefore Nature has provided but one Emunctory for the carrying them off, viz. the Ductus Biliaris, which empties it self into the Duodenum, and is conveyed off along with the Excrement of our Food by stool: Whereas there are Millions of Emunctories, besides that great Dis­charge that is made by Urine, to carry off the Volatile Alkaly. But if at any time the Glands of the Liver are ob­structed, that the fixt Alkaly cannot be separated from the Blood, what fatal Effects does it produce?

I have scarce ever known a true Ascites (which is that kind of Dropsy that is scarcely ever to be cured) which hath not had its Origine from an Obstruction of those Vessels in the Liver, which separate the Bile from the Blood. Nay frequently they have [Page 74]a Jaundice upon them thro the whole Course of the Distemper. But if not so, I never yet knew an Ascites that had not a Jaundice preceded it; and in what manner the whole Oeconomy of the Body is destroyed in this Distem­per, is but too well known. But this is not the only Distemper that hath its Origine from the Obstruction of these Vessels, tho it be one of the most dan­gerous.

Secondly, As for what you say con­cerning the Insipidness of the Taste of the warm Serum, I suppose you mean that Serum which is overheated in Fevers, &c. the Serum being always warm, whilst People are alive. I can assure you it is contrary to my long Experience; for of many Years, it has been my Custom to taste the Se­rum of the Blood not only in Fevers, but all other Distempers, where I have had occasion to prescribe Blood-letting; and in some Fevers I have found the [Page 75] Volatile Salt to bite my Tongue very severely, but never once could find the Serum insipid: and by this way of tasting I can better judg of the Con­dition of my Patient than from the Colour of the Blood. But in those Ca­ses where the Serum is much inviscated, as in most Pleurisies, Rheumatisms, and many Fevers, the Volatile Alkaly is so involved, that it doth not very strong­ly affect the Taste, tho it is never in­sipid that I could ever yet find. As for Volatile Salts being aculeated, and affecting the Palat strongly, I am very glad you take notice of it, since the general Notion that most people have of all Alkalies is, that they are of such a sweet, soft, mild Nature, that they carry a sanative Virtue a­long with them wherever they go.

Thirdly, I own that sulphureous Sub­stances are wont to sit uppermost in the Dissolution of Bodies; and that the Blood is impregnated with such Sub­stances, [Page 76]I am far from denying; but they appear in all respects to be equal­ly distributed through all its parts: but suppose they should sit uppermost here, and the Serum more impregna­ted with them than the globulous and fibrous parts of the Blood, Sulphureous Substances won't change Syrup of Vi­olets from blue to green; and the Serum abounding with those Particles that will do so, which are Alkalies, these Alkalious Particles by breaking and di­viding the Particles of the Sulphur will increase and excite the Flame, I have before taken notice of, to a more in­tense degree: For the Serum would not be the more hot, supposing it did abound with sulphureous Particles, unless the said Particles were some way or other enkindled.

Answ. In most inflammatory Cases, where the Blood is immediately affect­ed, there the Serum is viscous and sizy, being overcharged with Alkalious Par­ticles; but in those Cases you mention, and in some others, where the Blood is over thin, it is not the over Thinness of the Blood which is the only Cause of those Diseases, but a Destruction of the Tone of the Parts; and where the Tone [Page 78]of any Part is once spoiled, the great quantity of excrementitious Matter is soon thrown thence, and so the Violence of the Malady is increased: Besides, in Dropsies the Quantity of fluid taken in, they being always thirsty, is so very disproportionate to what is car­ried off, they always making Water but in very small quantities in pro­portion to what they drink, that it's no marvel that their Blood is over thin. I have frequently in Dropsies known People drink three Quarts in a day, when they have not pissed a Pint: And that Acids should occa­sion the Thirst that attends Hydropi­cal People, is ridiculous to imagine, when they are the only things in the World that will quench Thirst. Be­sides, do but consider the Nature of the Medicines that are most effectual to bring the Blood to a Consistence, when it is over thin. I have scarcely ever met with any thing equal to Ca­libeats, [Page 79]and that Steel is an Acid I have elsewhere endeavoured to prove: And as a farther Proof of it I shall produce the Testimony of Beckerus (no contemptible Man) in his Minera A­renaria, pag. the 88th. Non recensebo jam qualiter ille spiritus esurinus in aquis subterraneis latitans, varia sibi Salium, Aluminum, Vitriolorum, Sulphurum, Re­algarium mineralium compositionum species producat; nec demonstrabo, quâ ratione supra terram in Aeris regione tractus qui­dam hujus Acidi spiritus de uno Polo ad alterum, & perillum acus Magnetica fe­ratur. Hoc tantum hic loci allegabo, omne Acidum substantiae martialis esse, in quo­cunque oleo, pinguedine, fuligine, limo, silice & arena; imo etiam ipsa flamma re­peribile, ac ad oculum demonstrari posse: quaecunque ergo naturae Acidae & martia­lis sunt, illa potestatem habent Alkali tan­quam substantiam metallorum mercurialem alterandi & transmutandi. Now if this Thinness of the Blood be to be taken off, [Page 80]and the Blood brought to its due Con­sistence by the means of Acids, it is not reasonable to suppose that Acids should be the cause of its fusion. But then I confess here lies a great Diffi­culty, viz. how is it possible for Acids to make the Blood thin, when 'tis too thick and viscous, and to bring it to a due consistence, when it is o­ver fluid? To which I answer, That should I pretend to give an account what Acids taken in the proper Lati­tude would do, I should be guilty of the greatest Arrogance imaginable; for that would be to pretend to as much Knowledg as Solomon had, who knew the Virtues of Plants even from the Cedar of Lebanon to the Hysop which grows upon the Wall. And Divine Providence had determined him to be the wisest of Men that had ever been before him, or that should come after him. All Plants from the great­est to the smallest are principally [Page 81]composed of Acido-sulphureous. Par­ticles; for what Comparison is there to be made between the small quan­tity of fixt Alkaly that is to be found in the Ashes after burning, and of Volatile Alkaly in the Soot, in relation to the great quantity of Acido sulphu­reous matter that is spent in Flame? Or to come nearer to the matter, let a Pound of any Vegetable, which af­fords the greatest quantity of fixt Al­kaly, viz. Broom, or any such Plant, be sufficiently dried, so that the su­perfluous Humidity may be evaporated; after that is done, let it be commit­ted to Distillation per se, and it will afford between two and three Ounces of an Acid Spirit, with a good quan­tity of Oil, when all the Art of Man is not able to procure from the Caput Mortuum above two Drams of fixt Al­kaly, and, as is before observed, Broom is one of those Plants that affords the largest quantity of fixt Al­kaly. [Page 82]Now the Acid Spirit and Oil are those Substances, which in burn­ing serve to supply the Flame: and from the Caput Mortuum, unless it be afterwards burnt, there is no fixt Alka­ly to be obtained. But here again to obviate the Objection before taken notice of, viz. that the Fire may pro­duce new Substances, which were not existent in Bodies before, or that for instance, the fixt Alkaly to be pro­duced out of the Ashes of the Caput Mortuum of the Broom, is only the Pro­duct of the Fire: If this were so, why then the Ashes after all the Salt has been once extracted, being again commit­ted to a Violent Fire must produce more Salt; whereas on the contrary let it be committed to the Fire in the most violent degree of heat, and con­tinued there for never so long a time, yet it will never after afford the least quantity of Salt of any kind. But that I may return to answer the form­er [Page 83] Objection, viz. how Acids are capa­ble of making the Blood thin when o­ver viscous, and also to reduce it to its consistency when it is over thin: All the Bodies in Nature are differently specifi­cated by the all-wise Author of Nature, and at the same time are all animated by one Universal Acid Spirit, which is what the Antients were wont to call the Soul of the World, and I think not improperly. Now the more any Bodies are impregnated with this uni­versal Acid Spirit, and its beloved Sis­ter Sulphur, the more perfect they are; and Gold, which is one of the most perfect and durable Bodies in Nature, seems to be composed of nothing else but a pure Acidum and Sulphur, as I think has been sufficiently made ap­pear by some of the most strict En­quirers into Nature's Secrets. Now the more perfect any Bodies are, the more Acidum and Sulphur they contain, and afford the least quantity of Excre­ment, [Page 84]viz. Alkaly, that being the only Destroyer of all Bodies, and is what brings them to a state of Putrefaction and Corruption. Well, but what's all this to the answering of the Objection twice started? Why it's only to make my way clear. But I shall now ap­ply my self to it. There are two general sorts of Acids, viz. mani­fest, and inveloped ones: the manifest ones are such as immediately appear to the Taste; and these, altho origi­nally the same, proceeding from the same universal Fountain, yet have dif­ferent Operations upon Human Bodies. The inveloped ones are such as do not immediately appear to the Taste, but by taking of the Bodies asunder appear to be such. There is an Axi­om that, Unumquodque in id dissolvitur unde compactum est: Every thing is dissolved into that whereof it is made. Now if this Axiom be true, as I think it is an infallible one, a Man may [Page 85]reasonably conclude that those Bodies, which upon their Dissolution are re­duced into Acid Substances, are Acids, tho before their Dissolution they did not appear to be so. Most Vegetables upon the Dissolution of them, or ana­lyzing by the Fire, appear principally to be composed of Acid Substances; and therefore I think are to be ac­counted Acids, altho they are so dif­ferently specificated, and have such different Operations upon Human Bodies, that a Man who has not nicely exa­mined them, would be tempted to believe that the original constituent Parts of them were much more dif­ferent than they are. Now the more perfect and durable any Vegetable is, the greater quantity of Acidum and Sulphur it affords, and less of excre­mentitious Alkaly. And from the different Combinations of the two Sisters Acidum and Sulphur, I believe it possible to give a very probable Ac­count [Page 86]of all the differences in Plants as to Colour, Taste, &c. And as these two perfect (if it be lawful to call any natural thing perfect) Principles are more or less clogged with excre­mentitious Allkaly, so they are more or less durable as to themselves, and more or less friendly to Human Bodies, for whose use they were principally created; so that here you may see, that when I preach up Acids, it is not only Vinegar, Lemons, Oil of Vitriol, Oil of Sulphur, &c. that I recommend, but all the perfect Parts of the Crea­tion, and decry the use of those things that are the Principles of Death and Destruction in Bodies, viz. Alkalies. From what I have before said I think I may without Presumption, reckon Oak-bark amongst the number of A­cids; and yet Oak-bark being given in Substance, or a Decoction of it, is so far from making the Juices over fluid or thin, that it will reduce them to a [Page 87] Consistence, when they are so: the same may be said of Bistort, Tor­mentil, and abundance of things of that Tribe: the same thing will Com­fry Roots do, and all the things of that Tribe; the same I could say of many more, but here I have not room to expatiate. Asparagus, Par­sley, &c. will make the Juices fluid when they are over thick and viscous, and so will a multitude of things more of that Tribe. I could range my self out into the mineral Kingdom, but the different Operations of them are so well known to every body, that I think it needless to take any particu­lar notice of them: yet this much I will presume to say, altho it be fo­reign to my present Design, that af­ter having made all the Enquiry into the Nature of Metals that Human Indus­try is capable of, I am perfectly satis­fied that they differ one from another only in degrees of Purity; and there­fore [Page 88]for ought I know the Business of Transmutation is not so ridiculous a thing as some People would make it. As to those Acids that are manifestly so, they greatly differ in their Opera­tions upon Human Bodies. I have before observed that there are those which may properly be called Acido-sulphurea, and others Sulphureo-Acida: but in Nature I don't know a simple Acid or a simple Sulphur, there being such an indestructible Bond of Union and Friendship between them, that they are never one without the other. Now those Acids that have most Sul­phur united with them are Aperitives, Openers of Obstructions, and keep the Blood and Juices in a proper state of Flu­idity: Those that have little Sulphur mix'd with them are Stipticks, and bring the Blood and Juices to a Consistence, when they are over fluid. What I have said upon this Subject is not the effect of Fancy, but of a Series of [Page 89]several Years strict and nice Observa­tions.

Answer. If Alkalies cause Pain, I do agree with you, that Acids of con­sequence must give ease; but I don't suppose that an ill habit of Body, that has been perhaps some Months or Years a contracting, is to be altered with a few Doses of the most exalted Medi­cine in the World, let it be Acid, or what you please. But supposing A­cids [Page 90]to be the most proper Medicines in the World to ease Pain, as I believe they are; yet it is not improbable, but upon the giving a small quantity of Acid in such cases where there is a large quantity of Alkaly lodged up­on any Part, so as to cause Pain, it may only in part dissolve the Alkaly, which was before more fixt, and so by accident may exasperate the Pain; whereas by continuing the use of the Acid, the Alkaly would be perfectly dissolved and extirpated, and so the Pain would altogether vanish: But Pain being sometimes exasperated upon the first giving of them in too small quantities, has, I doubt not, been one great Cause of deterring people from proceeding in the use of them, and also of attributing to them the Cause of Pain: But in great Pains it is my constant Practice to ap­ply Acids externally to the Part af­fected, as well as give them inward­ly; [Page 91]and there are but very few Pains, especially Gouty and Rheumatick ones, that I am not able to overcome in a small time. And for the Pain you say you have often found to be excited upon the giving of Rhenish and White Wine, I have assigned a Reason for that, if they are drunk in too large quantities, both in my Essay of Alka­ly and Acid, and in my Tract of the Gout; and therefore shall not again repeat it, but refer you thither.

Answer. I can cure the Gout, if there were no such thing as Sassafras; I only use Sassafras in Apozems, as a proper Vehicle to dilute other Medicines [Page 92]in the Stomach. But however Sassa­fras is no contemptible Medicine; and if you will but give your self the trouble of Distilling a Pound or two of it in a Retort per se, if you afterwards reckon Sassafras amongst the number of Alkalies, I am mistaken; and if I am so, I shall willingly own it.

Answ. I own that upon the exhibi­tion of Syrup of Violets to Infants it will frequently occasion green Stools: But [Page 93]from whence doth that proceed, but from its Mixture with the Bile in the small Guts? and that the Bile is an Al­kaly I know not any one that doubts.

Answer. The Author you speak of is my singular good Friend, and a Man for whom I have a very great Value and Esteem; and as to the Truth of the Relation you mention, I can readily assent to it: But if you have read the Appendix to my Essay of Alka­ly [Page 94]and Acid, you cannot but remem­ber, that I there acknowledg that A­cids may sometimes abound in the Stomach, and cause a Disorder, but in no other part of the Body; which thing I have so fully handled in that place, that should I recite what I have there said upon this Subject, my Enemies would accuse me of Tauto­logy, and therefore thither I shall re­fer you: and if what I have there said be not satisfactory to you, I shall endeavour to give you what further Satisfaction I am able. As for the Cure of Infants Diseases, I don't see but that they require the same Methods to be taken with them, as with grown People, only the Medicines given them must be more mild and gentle, and in less quantities, considering the won­derful Tenderness of their Natures.

Answer. I have endeavoured to give you what satisfaction I am able as to the Objections you have already raised, and shall think no labour too much to answer any farther Objections you have to offer. I don't desire of you, or any else, to take up with any thing that comes from me, without [Page 96]examining it in the Balances of Rea­son and Experience; and if after such Examination you find what I have advanced to be Truth, I don't doubt but to find you a zealous Champion in my Cause: But if otherwise, I beg of you that you will convince me of my Errors, and I shall be very ready to write a Recantation. As for the Im­provements that have been made of late, they have principally belonged to Anatomy, and indeed they have been very considerable; and of all the Phy­sicians of Europe, those of our own Nation have had the greatest hand in them. But as for the Improvements in the practical Part of Physick (setting aside the Discovery of the use of the Peruvian Bark in the Cure of Agues) they are very inconsiderable: The most that has been done of that kind, was done by the indefatigably Industri­ous Dr. Sydenham, and I heartily wish that we had more Dr. Sydenhams at this day.

Sir, there are abundance of Imper­fections that you will meet with; but if you did but know the great hurry I have been in, and how little time I have had to sit composedly in my Study, you would readily pardon a great many of them: But this I can assure you, that had I not had an ear­nest desire to serve you with some other such Candid, Ingenuous Persons as your self, I would not have deprived my self of so many Hours Sleep (ha­ving little other time to command) as I have been forced to do, to put things in that Order they are: At present I have nothing more to add, but that I am