THat which I find most remarkable in Mr. Denis's Letter, is first, the Transfusion of the Blood of a Mangie Dog into a Sound one, to try whether the Mange would be communicated with the blood; the Mangie Dog is found cur'd; and the other who had received his blood, not become Man­gie.

The next is the Experiment upon a Youth, who had for the space of above two Months, been tormented with a contuma­cious and violent Fever, which (saies the Narrative) oblig'd his Physitians to bleed him twenty times, in order to assuage the excessive heat. Before this Disease he was not observed to be of a lumpish dull Spirit, his Memory was happy enough, and he seem'd cheerful and nimble enough of body: but since the violence of this Fever, his Wit seem'd wholly sunk, his Memory perfectly lost, and his body so heavy and drowsie, that he was not fit for any thing: to trouble you no longer with every particular of the relation; They opened his vein, and took a­bout three ounces of blood, so black and thick, it could hardly form it self into a threed to fall into the Porrenger: At the same time they brought a Lamb, whose Carotis Artery was prepar'd, out of which, they emitted into the Young mans vein about three times as much of its Arterial blood, as he had [Page 2] emitted into the dish, and so stop't the Orifice of the vein as usually in other Phlebotomies; being ask'd how he found him­self, he said during the operation, he felt a very great heat all along his Arme, but in brief, he presently became more cheer­ful and lively, eat his meat very well, and shew'd a cleer and smiling Countenance; the next day slept better, and from that time got the victory over his drowsiness, he had no longer slowness of Spirit, nor heaviness of Body, grew fat visibly, and is (saies Mr. Denis) a subject of amazement to all that know him.

Though Mr. Denis hath sufficiently answered the weak ob­jections aagainst the Practice of this new Art, yet, how the sound infus'd blood of one Animal, mingling with the infected Mass of another (and especially, of a different Species,) indu­ceth renovation and health into the diseas'd, without receiving infection from so desperate acommixtion, seems worthy of a further inquiry than has been yet made.

As to the Experiment of the exchange of blood, between the Mangie Dog and the Sound one, by which the first receives his cure, the other remains uninfected, Mr. Denis inquires whether the blood of the Mangie Dog were putrefied, and corrupted in his veins or not: As if putrefaction of the blood, were necessarily the efficient cause of the Disease; but by the common experience of Anatomy, the blood is found not to putrefy within the vein many daies after death; much less than it is to be suspected ordinarily of putrefaction in the living vein, where, by continual circulation, and the irrigation of the vital Balsome of its volatile salt, congelation, the beginning of putrefaction is most powerfully refitted. Besides, the Adepti know how to rectify the blood in all Fevers, the Gallenists call putrid, (citò tutò & jucundè) with the precipitate Diaphoretick of Paracelsus; But surely, if putrefaction be the repulsion of the Crasis of the thing putrefied, necessarily inducing a new form, the blood must either be granted not putrefied in the Vessels, or a regression from privation to habit, which is absurd.

In the same Experiment, Mr. Denis supposing the blood of the Mangie Dog to be wholly corrupted in his veins, imagines it [Page 3] probable that the cooler blood of the sound Dog, alaying the extreame heate of the other, may work the cure; ascribing the Disease to the Transpiration of corrupted blood, and that, to an extraordinary heat. But the blood being supposed to be vit [...] to prevent its difflation by cooling, were sooner to introduce death, than a remedy; besides, Transpiration is not the effect of heat effective, but excitative only; for the blood is prop [...]ly volatiz'd by the Vital spirit and its own Ferment, whose operation is more powerful than that of Fire; for Glass held for the last act of Fire, is really further reducible by the help of Ferment into water. So then the action of extream heat (such as is supposed here) would rather have desiccated and and fixt the blood than have mov'd it to Transpiration; Be it then properly the act of the Vital spirit and Ferment, and not of heat, and consequently no need of cooling in our case.

Now as to the Disease it self, I take it to be the excretion of an Acid salt from the blood, closing with Hippocrates Acidum, Acre, Amarum, Ponticum, &c. for Morbifick causes. This hostil Acidity (as we see in Tartar of Wine, which is no other than a congelation of the Acetous part of the Wine into Salt,) be­ginning some degree of fixation of the volatile Salt of the blood, contrary to the scope and intention of Nature, which is, to have it totally volatil and transpirable without any foeces, is by the prepotency of the Vital spirit and Ferment, driven out together with the half fix'd Salt into the skin, where for want of volatility, it sticks and turns to the Mange. Hence I suppose that if the sound Dog had been coupled up with the other for some time, he had been more likely to have received his con­tagion, than by the Transfusion of blood.

The Experience upon the youth labouring of a violent fever and cur'd by immission of the Arterial blood of a Lamb into his veine, is more observable, as being more applicable to pra­ctice; now As to the fever; I take it for a Maxime, Quidquid in sanis edit actiones sanas, idipsum in morbis edit actiones vitiatas. But in health the vital Spirit naturally warmes a man, the same Spirit therefore aestuates in a fever, vehemently striving to ex­pell [Page 4] the occasional matter of the Disease, and this I take to be the [...], or Spiritus impetum faciens of Hyppocrates Van Hel­mont proves this by the example of a thorne run into the fin­ger, which though both actually and potentially cold, never­thelesse quickly raises a burning, paine, and phlegmot in the part, inasmuch as the sensitive Spirit being hurt by the thorne, provokes the Archeus to expulsion, in which endeavour, the Spirit is first accended and then the part: Hence expert Physi­tians direct their cure of fevers and other acute Diseases, to the pacation of the Archeus, without purging or letting of blood; how contrary was the procedure of those Physitians who blooded this youth twenty times to asswage the heat of his fever; but to how little purpose these large profusions of blood are, may appear by the miserable death of Pr. Ferdinand Governer of Flanders, who in the year 41 fell sick of a fever, his Physitians (according to the method of these) with reiterated Phlebotomies so exhausted the stock of his blood, that being dead, and his Heart, Lungs, Liver, Veines, and Arteries dissected in the presence of Van Helmont, there was scarce found a spoonfull of blood left in his body, and yet the day before his death, he had susteined as violent a fitt of his feaver as at first; I leave it then to the Judgement of the indifferent Reader that hath not Subjugated his reason to the Authority and vulgar practice of others to the contrary, to judge whether Bleeding be a proper Remedy for a fever, when the Exantlation of all­most the whole Masse of blood, had not so much as made any Diminution of the Paroxisme. But to strengthen this my opi­nion a little further, which seemes to be singular, easily to gain credit, take this familiar Instance: Let a vessel of new Wine be­fore its clarification, be supposed to be agitated by a vehe­ment Fermentation, which motion in the Wine (as in our case of the fever) is stir'd up by the natural force and activity of its Spirit, striving to attain the vertue of its perfection, which cannot be but by the shaking off, and Separation of the Tarta­rous and other wild Heterogenious and Immissible parts from the truly Vinous and Homogenial; the scope of Nature is the very same in the fit of a fever, viz. Separation, now let any [Page 5] man to stop this Fermentation draw off a part of the Wine, and he shall soon perceive that although he hath lessened the quantity of the Wine, he has by this meanes made no alteration in the quality, the Fermentative principles in the remaining part, keeping still their natural Energie in proportion to the whole: but if an untimely Fermentation happen, tending to the destruction of the Wine, let him but cast in a due propor­tion of milk, and he shall quickly finde that furious orgasme of the Wine to cease; so that this turbulent motion in the Wine either ceases naturally, the Heterogenious parts being separated by due Fermentation, or else by Sedation, as in the experiment by milk, the like method seemes most rational in the cure of a fever, either by Medicines separative, of which I prefer Dia­phoreticks, or sedative without phlebotomie, by which there alwayes happens some irreparable losse; for though not only the blood, but influous Spirit too, be restorable by our daily food, yet the losse of the insitous or innate Spirit is never re­coverable by art or Nature; if it were it would not be impos­sible by art to render men immortal. If then either the insuc­cesfulness of the practice, or reason may prevaile; I advise the Gallenists to make use of powerful Diaphoreticks in rectifying the blood, or such sedative Medicines as can quiet the enor­montick Spirit, rather than this needlesse custome of Bleeding. Especially since the Angina, Peripneumonia, and Pleurisie can more speedily and securely be cured without it. The Experi­mentor here seemes to be well satisfied with his conceipt of stagnation of the blood in the vessels, thinking his opinion suf­ficiently confirm'd by the issuing forth of a blood blacker and thicker than ordinary upon the opening of the patients vein. But the Aethiopians in their youthful and most vigourous estate of health, are said to have their blood very black, with little or no Serum. And upon inspection of the blood of neer 200 several persons drawn in one day (it being a custome amongst the Bores in Flanders to be blooded upon a certain day) there were found all sorts of colours and consistencies the most dissi­milar imaginable to be found in blood, and the several men from whom such variety was drawn, all of them in a perfect [Page 6] state of health. Van Helmont (well acquainted with the excellent Medicinal use of the blood) goes further, and making choice of the most different sortes, First, tryes them by their analyses, then by their virtues, administring them prepar'd severally ac­cording to Art, and finds them (notwithstanding their diversi­ty of colours) of equal force in medicine; so that this sort of divination by colour seemes full of uncertainty. As Dyers out of the same vate, and same tinging liquor, at the same time give several colours, according as the several peices are various­ly praedispos'd; so perhaps the univocal liquor of the Stomack in its progression to the liver, meeting by the way with several Ferments, receives several tinctures, without any Depravation at all of its Substance. For proof of this the foregoing experi­ments may suffice.

Now as to the process; the Arterial blood of the Lamb, is immitted into the vein, of the man the Patient finds a great heat all a long his Arm but not any further. The reason per­haps why he finds a heat in his Arm and no further, may be the impetuosity of motion in the narrow chanel of the Arm by the irruition of a quantity of fresh blood, which entring by the sub­clavia into the large ascendant trunck of the Cava, though quickening the motion there, yet having more room and be­ing more immerg'd, the excessive heat ceases, for no more new blood enters this great channel than pass'd the lesser; be­sides, motion of impulse is so much the quicker, by how much it is neerer to the impellent. Nor shall I doubt to assigne the cure both of his side and fever, principally to the nimbler cir­culation of the blood of the Patient, actuated as well by the extrinsick motion of the Arterial blood of the Lamb, as by its tenuity, for it may probably be suppos'd much thinner than the Venal blood of the Patient, since naturally the Arterial blood is thinner and moves faster than the Venal. Nature seemes to teach us not only the use, but even necessity of a nimble circulati­on of the blood by stirring up quicker and stronger pulsations in the Heart and Artery during the crisis; here I must forsake Gal­len and not allow the principal use of the pulses to be Ad cordis refrigerium et fuliginum explosionem; for the Heart and Arterie of [Page 7] a frog (without need of refrigeration or fuliginous explosion, because actually cold) being dissected alive, pulse as in other Animals whose blood is actually hott; and if you will say that potential suffices; It seemes absur'd to suppose a thing barely in Potentia, Actu jam agere; it is more likely then on the con­trary, to be Ad caloris augmentum, and that for the most part; but alwayes for the production of the vital Spirit, and partici­pation of it, to the languishing mass; and this by traction of Aire by the Arterial veine and venal Artery into the left ventri­cle of the heart; for Gallen esteemes Air as it were the food of the vital Spirit, and the learned Chymists (not every distilling Mountebanck) know how by the help of Air, to volatize the most fixt Alkalious salts, that the force of the most vehement Calcination can produce: so then Nature seemes rather to intend Volatization than Refrigeration, by the pulses; for as Bartholinus observes in acute fevers, and most violent Ebullitions of the blood, the pulse is often weak and low, which otherwise ought then to be strongest. This being grant­ed, let us see in our case, what probability of quickening, the motion and volatization of our Patients diseas'd blood by this immission of the blood of a Lamb; and what other bene­fit may occur by this commixion tending to a cure.

I have already shew'd how the motion of the Patients blood, might be advanced by the Impulsion and Attenuation of the other; there is yet a more natural way, which is, by the in­duction of a new Ferment. This, Hippocrates calls Divine, and is the undoubted parent of natural motion, Cum tendentia (says the excellent Dr. Willis in his book de Fermentatione) ad perfectionem, vel propter mutationem in aliud. Now the motion requir'd in our case, tending to the Melioration of the blood, and consequent cure of the fever, is, that it be throughly volatiz'd, and dispos'd to an easy transpiration; Hence Para­celsus and Van Helmont (next to their great universal medicines conquering all diseases) commend the volatil salt of Rosemary, Sage, Rue, &c. for the cure of fevers, and the volatil salt of Tartar, for the cure of allmost all diseases; wee see how soon a little Spirit of Wine cheers and quickens the vital Spirit, [Page 8] by mingling it self presently with it by reason of their Ana­logie; but the Spirit of Wine is nothing but the solution of its volatile Salt; for it may by the spirit of Urine or Salt of Tartar, be corporified into a manifest and palpable saline concretion, and indeed it is in this instance by contact of the Vital Ferment presenty turn'd into a volatile saline nature, such as is the Vital spirit it self. Now that the Vital spirit is of a saline nature, seems evident by the testimony of Sense, for if a part happen to be torpid or benum'd, by any accidental prohibition for a while of the influx of the Animal spirit, which acquires no for­mal transmutation in the medulla oblongata, nor other difference from the Vital, sane gradu perfectivo, upon the return I say of this spirit to the succour of the part labouring, we find a kind of stinging and pricking, and infallible Index of its saltness; as is its total difflation in healthful bodies, of its volatility: I mean here the Influous spirit, which is continually restor'd, not to the Insitous, whose decay is naturally attended with irrepairable weakness and its total extinction or efflation, with present death. Let us now see if we can find such active principles in the blood of the Lamb thus emitted without diminution of its vital energie, as may suffice for the actuating of the languishing Ferment of the blood of the Patient.

It cannot be deny'd, but that the blood of Beasts as well as men, is full of Vital spirit, and volatile Salt. Fernelius (de spiritu viventium) defines the spirit of all living creatures to be Corpus aetherium, and Aristotle holds it to be of a Caelestial Divine nature; answering to the Element of the Starrs. There cannot pro­bably then be so great a dissimilarity between the Vital spirit of the Lamb, and that of the Man, but that the first, (elabora­ted in its way to the patients heart, by the Action of the Innate spirit implanted in every part, and afterwards by the force of the Vital Ferment in the left Ventricle, which Helmont calls (Maxime vitale & luminosum) may easily be transmuted, and assimilated into the latter; and the Archeus of the Patient thus fortified might well overcome his disease, Nature being her self (if freed from impediment) Morborum Curatrix.

[Page 9] Now as to the volatile Salt, it may be esteemed the Balsome of life, and preserver of the whole body from corruption, upon whose Oeconomy depends the just Circulation, and (as I said) the Difflation of the blood; and upon these, the preservation of the life of the Individual: This Salt resolves the Congelations of extravasated blood, opens Obstructions in the Veins, resists and conquers Acidity; Omnem Aciditatem quam attingit, perimit, saies Helmont; but Acidity (according to him) out of the stomack is inimicous to the whole body, Exorbitans Pestilensve impressio est in cruore si acescat, ast si à venis spreta ejiciatur, Apostema parit ubicun (que) id locorum contigerit. Besides these more than sufficiently power­ful Operations of the Vital spirit and Volatile Salt, there are yet in the blood innumerable secret medicinal Virtues. The blood of a sound man prepared according to Paracelsus, is al­lowed by the consent of the most learned and experienc'd Chymists, to cure Radically the Epilepsic Palsie, Apoplexie, ex­ulcerated lungs, and Pleurifie; and (if Faber deserve credit) may worthily be esteemed amongst the greatest Arcana. The blood of an Asse is said to cure a Quotidian Fever, and of an Asses Colt the Yellow Jaundies. The blood of a male Goate rightly prepar'd (for as 'tis found in Apothecaries shops it failes) certainly cures the Pleurisie and Peripneumonia. The blood of an Oxe is said to cure the Dysenterie. The blood of a Cat cures the Falling-sickness and Herpes. Of the blood of a male Deer is made a Balsom against the Gout. The blood of a Fox is an excellent remedy against the Stone in the Reins or Bladder. If then Blood extravasated be endued with so many admirable and powerful virtues, what may we expect from it communicated (as in this our Experiment) without any loss at all of its mumial virtues? surely such an addition of Vital trea­sure to the depauperated store, must needs enrich it with new strength, quicken all the Vital faculties, and might with very good reason overcome our Patients Fever.

There is yet a consideration which perhaps may not seem vain to such as are acquainted with Hermetick Philosophy, and 'tis this, a Lamb is esteemed to be the meekest and most peace­able Animal Nature has brought forth; why then might not his [Page 10] blood sigillated with conformable Idea's, by the imagination of the Archeus, introduce such a pacation into the tumultuous blood of the Patient as was sufficient for his cure? For thus cer­tain Arcana prepared by secret Art (unknown to all vulgar Chy­mists) by inducing onely rest and in the Enormontick spirit, are esteem'd by Paracelsus and Van Helmont (and some of them known to my self) for almost Universal Medicines.

Since then the practice of this new method of Healing by Transfusion of Blood, seems to be warranted both by reason and experience, I advise the curious Experimentor, to make trial upon Animals of the longest life, such as are Staggs, Eagles, Crows, &c. for the prolongation of life; And in the cure of Diseases, to make choice of such Animals as by their speci­fick proprieties are found to have curative virtues peculiar to several Diseases.

And thus I have given a guess at the reason of this new and (till of late) unheard of way of curing, by Tranfusion of Blood, which if I have err'd, let it serve for my excuse, that no man has gone before me to shew the way.