A LETTER OF FRANCISCO REDI Concerning Some Objections made upon his OBSERVATIONS About VIPERS: Written to Monsieur BOURDELOT Abbot, and Lord of Conde and S t. Leger.  
And Monsieur ALEXANDER MORUS.  
Printed in Italian at Florence, 1670.  
Now made English.  
Together with The SEQUEL of NEW EXPERIMENTS upon VIPERS, and a Dissertation upon their Poison: Serving for a Reply to a Letter written by Signior Francisco Redi to M. Bourdelot, and M. Morus.  
Written in French by Moyse Charas. Now likewise Englished..  
LONDON, Printed by T. R. for John Martin Printer to the Royal Society, at the Bell in S. Paul's Churchyard, 1673.   

A LETTER OF FRANCISCO REDI, Concerning some Objections made upon his Observations about Vipers.  
Written to Monsieur BOURDELOT, AND Monsieur ALEXANDER MORUS.  
SIRS,  
FROM your liberality I have received the Book entitled NEW EXPERIMENTS upon VIPERS, learnedly composed by those noble Virtuosos, who during some months had met in the House of M. Charas for that purpose. I have read it over more than once with great contentment, plainly finding that those Worthy persons have not scrupled by their eminent labours to confirm the Truth of those Observations, which I also had made touching VIPERS, until the year 1664.  
And indeed I think myself much obliged to their ingenuity, and do frankly acknowledge, that whatever worth that rude and plain piece of mine may have, it hath received it from the honourable testimonies, given to it in France, where all the excellent Sciences and Arts do highly flourish, to the admiration of those that profess them in the other parts of Europe.  
I entreat you, Sirs, that you would do me the favour to represent upon occasion these my candid and cordial sentiments, and withal to declare the high esteem I have for that Book▪ the authority of which is so venerable with me, that, having found therein some few things directly contrary to my own Experiments, I have often doubted of myself, and been almost ready to believe, that I dreamed when I made, and when I wrote them. But some of my Learned Friends, that were frequently present at those my Operations, have laughed at me for that proneness of my belief, and between jest and earnest assured me, that those Experiments had by no means so succeeded with me in a dream. Notwithstanding which, without any regard to their asseverations, I resolved to iterate and reiterate them, and that with so great and careful diligence, that I should greatly injure myself and Truth, if I should not freely and candidly tell you, that all those four or five Experiments, which to those Gentlemen in France have not succeeded, do succeed with me in Italy without fail, as they were formerly recorded by me; on the contrary, those will not succeed with me that have been made in France and are contrary to mine.  
And since you may perhaps have the curiosity as to desire to know of what kind they are, I shall here give you a brief account of them; assuring myself, that it will be acceptable to all the Lovers of Truth, but especially to the Authors of the Book of the New Experiments, who have been induced to write by no other motive than the sole desire either to confirm or to find the Truth of a matter so curious, of which so many understanding men have written.  
In my Letter then of the Observations about Vipers, addressed to the Illustrious Lorenzo Magalotti, speaking of the Poison of those creatures, both what it is, and in what part of the Body it resideth, I affirmed (as I affirm still) that the Poison of a Viper is nothing else then a certain yellowish liquor, which lodgeth in the vesicles that cover the greatest teeth of the Viper; and that that Juice is not only poisonous, when it is ejected by the live Viper when she biteth, but also when 'tis collected from a dead Viper, and even such an one that hath been dead many days, provided it be made to pass into a wound, and remain there. Moreover, I added, that this same liquor, when taken down into the stomach, is not deadly, no not so much as noxious. And this was my opinion, which hath been confirmed to me by innumerable Experiments, made with the greatest exactness I could employ.  
But the Authors of the Book of the New Experiments do resolutely write, That that above mentioned Liquor is not poisonous, but a mere and a most innocent Saliva or Spittle. Thence they go on to affirm for an undoubted and experimented Truth, that the Viper hath no part of her body, neither limb nor humour, able to poison; and that all her poison consists in the sole imagination of the Viper, irritated and made angry by the Idea of vengeance, which she hath conceived in her head; by the means whereof the spirits being put into a violent motion, are darted through the Nerves, and at times through the Fibres of the cavities of the Teeth, by which cavities those spirits are carried to infect the blood of the animal, by the opening made with the biting teeth. In short, they conclude, that if a Viper be not angry, and have not that vindicative imagination, her bitings do never poison, but are very innocent, causing no mischief at all to him, in whom they are made. For these are their words;  
Pag. 36. in the English Version, These considerations, supported by many Experiments made by Us, and to be related hereafter, have induced me to call these GlandsSalival, and to ascribe to them the very source of that yellow liquor, which hath been so much decried, and withal so little known; and it nothing else, but a pure and a very innocent Spittle. I hope that those who shall take the pains of examining after me, these Glands, and this Juice of the Gums, will not stick to give me their suffrages.  
Item p. 105. 106. But not to stay upon principles so slightly established, and ill maintained, for as much as we have on our side a great number of Experiments, upon which we are grounded: We say, that this Juice is nothing but a pure and plain Saliva, of which we have already observed the use; and that this Juice contributes nothing to the venomousness of the Biting, since being tasted and swallowed (as we have often experimented) it doth no hurt to man or beast; and since also, being put upon open wounds, and upon incisions made in the flesh, the same being rubbed therewith, and mingled with the blood, it annoys nothing at all; notwithstanding the judgement of a Person very intelligent, and particularly in this subject of Vipers, who assures to have made a great number of Experiments, which being contrary to ours, the great opinion we have of the abilities and the sincerity of that famous man, hath obliged us to employ the more care and exactness, and to confirm ourselves by a very great number of Experiments, which have always been found alike in the truth we here assert, and of which we shall make evident and irrefragable proof.  
Item p. cog. We conclude therefore, that the imagination of the Viper, irritated by the idea of revenge, which she had framed to herself, gives a certain motion to the spirits, which cannot be expressed, and bushes them violently, through the Nerves and their Fibres, to the cavity of the teeth as into a funnel, and that from thence they are conveyed into the blood of the animal by the opening, which they have made, there to produce all those effects, of which we endeavour to give a reason.  
Item pag. III. However this be, we must herein agree, that this irritation in the fancy or in the spirits of the Viper, is the main cause of the activity and piercingness of its venom, and that without it the biting would not produce such surprising effects, as those are, of which we have related so many examples.  
Item pag. 138. These Experiments will prove on the one hand, that the yellow liquor contributes nothing to the poison; and on the other, that these incensed spirits, assisted by the openings, which the great teeth had made for them, are the sole and true cause thereof.  
These sentiments they confirm by some Experiments, all which consist in this, that they had dropped a quantity of that yellow liquor into the wounds of a Pigeon, a Dog, and some Pullet's, which yet died not of it; and that having caused a Pigeon to be bitten by a Viper not enraged, the animal received thence no hurt at all. For they say pag. 115. We also made a trial upon a Pigeon, which we wounded under the wing and in the Leg in the same moment of time; and we let into each wound some of this yellow liquor, which just afore we had drawn from the gums of two enraged Vipers; then we rejoined the skin well, to enclose the said liquor, and we bound both wounds over with a band, that nothing might run out. We can assure, that the Pigeon felt not any inconvenience from it, and that we even found upon the wound, made in the Leg, a coagulated drop of the juice, round, and of the same colour as we had put it there, and the blood of the wound dried, and that, soon after, both wounds were dried up, and healed of themselves.  
Pag. 116. We also made the like Experiment upon a Cat, which we purposely wounded in the Leg, but he received no harm at all by it: We have also often experimented it on Pullet's, and other Pigeons, but always with the like success, and without any offence to the Animals.  
Ibid. The same Trial hath been thrice made at three several times, and even twice in one day upon a Dog, whom we had wounded on purpose towards the bottom of the Ear, where he could not lick his wound; and no mischief at all followed upon it.  
Ibid. We cannot but add here an Experiment of the mortal effect of the Enraged Spirits, without any intervention of the yellow liquor. We made a Viper several times to bite upon a slice of bread, by pressing every time its jaws against the bread; and we did this so often, that not only that juice was altogether exhausted, but the blood began to come out of the Vessicles. At the same time we vexed the Viper, and made her bite a Pigeon in the most fleshy part; and we observed that indeed the effects of the venom of the biting were not so quick, the Pigeon not dying but an hour and an half after it had been bitten; but then we found also, that the teeth of the Viper were in a manner covered with the crumbs of the bread, from the force of her having bitten at it, and that that had hindered them from making a deep entrance; and that having half stopped up the pores of the teeth, a good part of the angered Spirits could not come forth; so that the death of the Pigeon could not follow so fast, though yet it happened without any mixture of the juice, which had been altogether emptied.  
Pag. 138. The wound made by a Viper not vexed, whose Jaws were held in, and whose teeth were at the same time thrust into the body of a Pigeon, which also was accompanied with store of the yellow juice, and yet not attended with any ill accident.  
To these Experiments I have nothing else to oppose, but those very many ones, that were made by me in the year 1664. and recited in the abovementioned Observations of mine about Vipers, and those also that I shall recite hereafter, made likewise by myself, not with a desire to confirm the first, but indeed to discover the Truth. And, that I may not be put often to repeat some things, I shall premise some General Observations, made by me at the time when I dealt in Vipers.  
1. A viper more easily kills a Pigeon, a Pullet, a Turkeycock, a Squirrel, a Dormouse, and generally all small Birds and Animals, than a great Animal, as a Sheep, a Deer, a Horse, a Bull; yea these greater ones and those that are of an hard skin, very often a Viper kills not at all.  
2. According to the bigness of the Animal bitten, and according to the place where the Viper biteth, death follows sooner or later; especially according as the place wounded is a clear texture, or thick set with veins and arteries; or those veins and arteries are very small or big.  
3. If from the wound of a Viper much blood issueth, it sometimes happens, that the Animal nor only dyeth not, but does not so much as feel any great inconvenience.  
4. It doth also not seldom fall out, that an Animal bitten by a Viper suffers grievous Symptoms from the poison, which bring it near death, but yet kill it not; but the creature without any help of Physic and by the sole work of nature recovers.  
5. Those Animals that are bitten of a Viper die a little sooner, than those, into the wounds of which hath been on purpose conveyed that yellow liquor, which by art hath been fetch't out of the bags of the teeth of that Viper.  
6. 'Tis necessary, that great dexterity be used in making the said liquor to penetrate into the wound; because, if the wound be narrow, it pierces difficultly; if large, it cannot be otherwise but it will bleed, and with that blood the said liquor will turn back, and so the poison come out again.  
I had then provided a good number of Vipers which I caused to be brought me cut of the Kingdom of Naples▪ and having in this month of May, 1670 wounded ten Pigeons of the bigger sort in the thighs, I put into them some of the yellow liquor freshly taken out of the mouth of the live Vipers; and all these Pigeons, some within the space of one hour, some in half an hour, and some in two hours, died. This Experiment I repeated upon ten Chickens, likewise wounded in their thighs, with the same event that had befallen the Pigeons.  
Then I cut off the heads of eight Vipers, and all the heads being cut off, and the Vipers quite dead, I thence extracted the poison, and caused them to be put into the wounds of eight Turtle-doves, all which died in the space of half an hour.  
In the month of June, having killed many other Vipers, and gathered out of the bags of their teeth and their gums all the yellow and viscous Juice that was there, I anointed therewith some beesom-rods, sharpened like arrows, and immediately I pricked with them ten young Pigeons in the more fleshy part of their chest, leaving them fixed in the wound; and the Pigeons survived not above two or three hours. But lest it should be doubted; whether these Pigeons died not of the wound itself, enraged by the punctures of those rods, I made a trial upon four other Pigeons with rods not infected with that poisonous liquor; but none of them died, though the wounds became purulent.  
I also took eight heads of Vipers, cut off six hours before, and, the Vipers being quite dead, I caused eight Turtle-doves to be bitten by them in the thigh, and not one of them escaped.  
Moreover I made the heads of fifteen Vipers to be cut off: and put them into a glass-vessel well covered, having laid them upon one another, that so they might remain moist. Four days after, I struck with those heads five young Cocks, and five great Pigeons in the thigh, and they all after a little while died. The like fell out with other Viper-heads, which having been killed six days before, had in all likely hood lost all choler and thoughts of revenge. And to prevent all Objections that might be raised on this occasion, I shall not omit to relate to you, that about the beginning of August when two of my Vipers, that alone were left me in a box, died of themselves of sickness, I caused two Turtle-doves to be struck by them, which also, like the former, died in less than an hours time.  
But I may go further. I had collected in a glass all the poisonous liquor of the heads of two hundred and fifty Vipers, to make various Experiments therewith upon occasion. But being by much business hindered, I delayed to accomplish my design: Whence that liquor turned first into a glue, coloured like amber; then in 30 days it became altogether dry and friable, so that it could easily be reduced to powder. Being pulverised, I had a mind to try, whether that powder, let into a wound, did keep the force of poisoning; and I found that really it did so, all those Pullet's, Pigeons, and Turtle-doves, into the wounds of which I had put some thereof, dying of it in a little while.  
Having made this Experiment, I began to doubt, whether that poison of the arrows of the King of Macassar in the Island of Celebes, which commonly are called the arrows of Bantam in Java Major, were not the poison extracted out of the mouth of some Viper, or of some other Viperlike serpent, and perhaps of a more malign nature because of the diversity of the Climate. I am not much averse from believing this to be so; and it may be confirmed by what I have read in Pliny, viz. That the Scythians did infect their Arrows with a Viperin poison. His words are, Scythae sagittas tingunt Viperinâ sanie & humano sanguine: irremediabile id scelus mortem illicò levi tactu assert. And this was perhaps extracted by Pliny out of Aristotle, who in h●s Book, entitled 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉, soon after describeth the process of preparing it, which I dare not affirm to be the true one, or to requi●e so many circumstances and cautions. And who knows, whether the Arrows of Hercules, of which the Fables allege that they were imbued with the blood of an Hydra, were not infected with this poison of Vipers? So 'tis believed by Diodorus Siculus, when he saith, 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉. And Ovid gives the name of Viper to the Hydra, when in his ninth Book of Metamorph. he saith; Pars quota Lerneae serpens erit unus Echiánae. And afterwards; 
— Capit inscius heros,  
Induitur que humeris Lerneae virus Fchidnae.  To which may be added, that Philoctetes, the Heir of the Bow and Arrows of Hercules, being gone in the Grecian Navy to the Trojan War, and having unawares wounded himself (as Servius Grammaticus relates, l. 3. Aeneid) with one of his Arrows in the foot; was left among the Grecians in the Isle of Stalimene, by reason of the violence of the pain, and the intolerable stench of the wound. Whence Sophocles, alluding, it seems, to the kind of poison, in a Poetical way and phrase relateth, that Philoctetes was left in that Isle, because he had been bitten by a Viper. His words are; 
〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉  
〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉  
〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉,  
〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉  
〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉  
〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉  
〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉  
〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉: That is  O Son of Achilles, I am he, whom thou mayst have heard to be the possessor of the Herculean Arrows, the Son of Paean Philoctetes: whom the two Armies and the King of the Isle of Cephalene shamefully left lying here, pining away by a cruel disease, struck by the fierce bite of a murdering Viper.  
And Cicero himself in his second Book of the Tusculan Questions, and in his Book De Fato, and many other Writers do follow this opinion, viz, That Philoctetes was bitten by a Viper. And possibly all of them had an eye not only to this place of Sophocles, but also to what Homer said before, in his sixteenth Book of Iliads.  
And though against this conjecture it may be said, that the poision of Vipers is inconsiderable in respect of what Poets do write of the Arrows of Hercules, which by them are said not only to have the force of killing without fail, whether the wound be small or great, as happened to the Centaur Chiron and to Nessus; but also that the blood of their wounds was become so pestiferous as to infect any live body whatsoever, touched thereby, and that with such violence, as to make the flesh fall off from the bones: which, they add, was experimented by Hercules to his great mischief, when his Shirt was tinged with the blood of Nessus; whence Ovid saith, 
Victa malis postquam est patientia, reppulit arras  
Implevit que suis nemorosam vocibus Oeten;  
Nec mora, letiferam conatur scindere vestem;  
Qua trahitur, trahit illa cutim (faedumque relatu)  
Aut haret membris, frustra tentata revelli,  
Aut laceros artus & grandia detegit ossa:  This is a Poetical Fable; whence, I am apt to believe, is raised that relation concerning the Arrows of Macassar, of which 'tis said, that they kill one in that very moment he receiveth the slightest wound thereby, and that also in the space of half an hour the flesh of the killed person becomes so putrefied, that it falls off from the bones in many pieces, whence do exhale such virulent steams, that if they light upon any ordinary and not envenomed wound, they mortally infect it, and without fail kill the Patient.  
I do here affirm, that I have made many tryal's with those Arrows of the Indians; but have not found them in Tuscany of so fierce and malignant a nature, as hath been related. The Dogs I wounded with them, died some of them in six, others in seven, others in twelve, others in twenty four hours. And their flesh was not putrefied, nor fallen in pieces, nor did their blood or exhaled steams at all kill other wounded Animals. But I have often observed, that, if one intends to ki●l with these Arrows, it is not enough to make a simple incision of the flesh, but he must by art make them stick a while in the wound (which is like to what happens in putting into wounds the powder of the dried yellow liquor of Vipers:) Whence it is that those Savages make of Wood the sharp ends of those Arrows, imbue them with poison, and then join them to the Arrow stick in such a manner, that those ends ever remain in the wound, whether the Arrow do break or be drawn out; as came to pass in the Siege of Jerusalem to those Heroes of Flanders, Godofred and Robert, of whom that great Florentin Poet thus singeth: 
Sospingeva il monton, quando è percosso  
Al Sig. de Fiaminghi il lato manco,  
Si che travia s' allenta, è vuol poi trarne  
Lo strale, e resta il ferro entro la carne:   
That is, The Engine discharged▪ the left side of the Flandrian Princes was so struck, that they were thrust out of their way, and when they would draw out the Arrow, the Iron stuck within their flesh.  
It is therefore necessary, that the Arrows do stick for some time in the wound, if they shall kill: Whence I understand not, how the vulgar comes to fancy, that the Blades of Swords may be envenomed. I do well remember, that with the yellow liquor of Vipers, and with other things esteemed venomous, I have sometimes slightly tinged Lancets for letting of blood, and with them have cut the vein of some Animal or other, but death hath not followed upon it. Let suspecting men rather beware of the Tents of Surgeons; for 'tis too hard to cause death by poisoned Lancets or other such Iron instruments. Hence it seems to me to savour of the fable (though the case be different) that Parisatis the old Queen of the Persians, did poison her Daughter-in-law by the hands of her Carver, poisoning the one side of the Knife, and therewith cutting asunder a Fowl, of which he gave to the young Queen to eat that part, which the poisoned side of the Knife had envenomed, eating the other part himself.  
I could never see the truth of what is related of poisons killing by a mere and momentaneous contact, or by vicinity alone; as that Stirrups, Saddles, and Benches have been poisoned, and thereby proved mortal. Let him believe it that will; I cannot. And what a certain modern Writer relateth for a great truth, concerning a prodigious accident happened by a kind of Serpents bred in the Indies, I must leave to himself, who saith, After I have spoken of these Serpents, I presume it will not be unacceptable to give an account of the strange effect they produce. If perchance it happen, that they pass over a cloth or shirt dried in the Sun, there is wont to be bred in the Kidneys of those that use this cloth, a certain kind of Serpents, which little by little growing up do encompass the whole body, and when their tail reaches their head, to conjoin the circle, than death is unevitable: Wherefore, to avoid this mischief, they kill them with Razors and Lancets, to prevent their growth.  
You have found above mentioned three persons, wounded by the Arrows of Hercules, namely Chiron, Nessus, and Philoctetes. The two first died suddenly; the third, after a long sickness escaped. If the causes of this difference were to be given (whether it be an History or a Fable) I should say, that Nessus and Chiron died, because they were wounded whilst Hercules was yet living, by Arrows freshly envenomed; besides that Nessus was pierced through his heart, as Ovid hath it, 
Jámque tenens ripam missos cum tolleret artus,  
Conjugis agnovit vocem, Nessóque paranti  
Fallere depositum; quò te fiducia, clamat,  
Vana pedum violente rapit? Tibi, Nesse biformis  
Dicimus, exaudi, nec res intercipe nostras.  
Si te nulla mei reverentia movit; at orbs  
Concubitus vetitos poterant inhibere paterni.  
Haud tamen effugies, quamvis ope fidis equinâ,  
Vulnere, non pedibus, te consequar. Ultima dicta  
Re probat, & missâ fugientia terga fagittâ  
Trajicit; extabat ferrum de pectore aduncum:  
Quod simul evulsum est, sanguis per utrumque foramen  
Emicuit, mistus Lernaei tabe veneni.  But Philoctetes was wounded long after the death of Hercules; whence 'tis credible, that those Arrows had lost much of their poisonous force, even as the powder of the yellow liquor looseth of its force, and the Arrows of Macasser by length of time grow languid; which though they poison and kill if one be wounded therewith, yet do they no hurt at all, if their poison be swallowed and taken into the stomach. Which Experiment I have tried upon two Dogs, to whom I gave to swallow two pieces of flesh covered with the powder of the scrape of such Arrows; as also upon several Chickens, to whom I gave the water to drink, wherein those shave had been a long time infused.  
But, to return after this long digression to the main thing; you may by the above related and often repeated Experiments, see, that the po●son of the Italian Viper consists not in an imaginary idea of anger raised to revenge, but rather in that yellow liquor, which is voided out of the bags of the bigger teeth of Vipers; which juice if it chance to be spilt in the mouth and upon the palate of those animals is able to envenoin the spittle which moistens their throat.  
I should think it very well worth while for those learned Authors of the book of the New Experiments, that they would please to make their Experiments anew. And if they shall find them conform to those they have already published, and really contrary to mine, than we may unanimously conclude, that we have lighted upon a truth hitherto unknown; which is, That the Poison of the French Vipers consists in an imaginary Idea of a revengeful anger; but that of the Italian ones hath its seat in that yellow liquor, so often mentioned by me. But if on the other side, the French Experiments should not hold, than it may be affirmed, that the French as well as the Italian Vipers are of one and the same nature; and have the same kind of poison.  
Wherefore if in Italy the Viper in poison certainly lodges in that yellow liquor, it will be no untruth in me to affirm, that if by biting, a Viper should have lost all that juice residing in those bags, and that also which may be furnished by the neighbouring parts, it will, I say, be no untruth in me to affirm, that the subsequent bitings will not be mortal: which is the thing I have these many years asserted, and do still assert, although the abovesaid Authors deny it, giving out that one only Viper, being vexed and swelled with choler, is able to kill as many animals as she bites; they trusting to one Experiment, in which they say there died five young Pigeons by the biting of one only Viper. We hope (say they, p. 137.) that among the many Experiments those of the five Pigeons, bitten one after another, by one and the fame viper exasperated every time, and of which the last bitten died first of all, when the viper was most vexed, and most exhausted of its yellow liquor, etc.  
I am willing indeed to believe the fact to be true; but for the confirmation of it I wish they had caused many more such Pigeons, and many other animals, of different kinds and bignesses, to be bitten of the self same Viper, which had killed those five ones, to see whether that angry and choleric poison had an infinite power. For when I examined this matter, I chose about the beginning of May a Female Viper, one of the biggest and lustiest, and vexed her to bite ten Chickens one after another, in the right thigh; of which the first, second, and third died almost in an instant; the fourth seemed only to be sick; but the fifth and all the rest did not only not die, but were not at all sick; and yet every time the Viper did bite, I angered and madded her exceedingly. In the month of June I repeated the experiment in five tame Ducks, bitten by one and the same Viper, which also immediately after bit three young Turtle-Doves. The first wounded Duck died three hours after; the second, five hours after; but the rest escaped. 'Tis true, that the first wounded of the Turtles died, but not the other two. Of twelve Ringdoves at one time there died but four; but the next day of twelve others there died six. Of five Rabbits there died three▪ and of three Lambs the two last lived, the first of them dying two hours after it had been bitten.  
I should be too tedious, if I should relate to you all the other experiments: Wherefore I shall go on to add, that having written in my Observations, that that yellow liquor was not conveyed to the bags of the teeth from the bladder of gall, I did suggest, whether it might not be disgorged there by certain several Ductus', that might be inserted at the head of them: which did appear the more probable, because that in all Vipers at the bottom of those vesicles I had always found two glanduls, which had not, that I knew, been observed or described by any body. Whereupon the Authors of the New Experimentsdo affirm, that they could never see such Glanduls as I had named; but that instead of them they had found two others, which they call Salival, thus by them described, p. 31, 32. I believed at first, following Signior Redi, that there might be Salival vessels in Vipers, as there have been lately found in Man and divers other Animals; so that after many researches made with sufficient attention and patience, in many Viper's heads I discovered at length such Glands, proper to form this juice, and to convey it to the Bags; and after I was well persuaded of it myself, I showed them to divers of those knowing Physicians, that had met at my house the last year. These persons had a mind to see them with their own eyes; and after I had well examined the parts which I showed them, they not only found them true, but they also saw there a greater number of smaller vessels than had appeared to me, of which some that are Arteries and Veins pass above the Glands, and others that are Lymphducts run below; so that they judged, that I could confidently assert and describe these Glands which I call Salival, and which they had acknowledged together with me; though Signior Redi durst not speak positively of them, because he had not discovered them; neither had they been described by any Author of their knowledge, nor by any one of mine.  
And pag. 35. As to the small Glands, whichSignor Redi hath observed at the bottom of the Vesicles that contain this juice, I can say, that I have with great care and diligence searched after them, and that 'tis true, I have there found the appearances of Glands, but having opened them, I saw nothing in them but small teeth that were fastened there, without finding any thing of a Glandular nature there, nor that did in the least approach to the shape, substance, or qualities of the Glands which I have been describing, etc.  
I do not at all wonder that those Writers have not found those Glanduls I named, I seeing they went about to search them within the Vesicles of the teeth, and at the bottom of them: Whereas I never said that they were to be found within them, I said they were to be found Sotto'l fondo (under the bottom) of those bags, and in good Tuscan language, 'tis another thing to say nel fondo, (in or at the bottom) another Sotto'l fondo (under the bottom.) And therefore when they ●ought them where they are to be met with, they easily found them, and they are the same which they describe, neither are there any other considerable glanduls to be discovered in the heads of Vipers. Nor could I at all write that those Glanduls lay in the bottom of the Vesicles, if I was of opinion that the yellow liquor did run into them after it had passed through the Salival Conduits, which yet I imagined might have their origin from, or connexion with those two Glanduls seen by me, and therefore must needs be in a situation a little distant from the Vesicles, and not in the bottom of them. Now whether these Glanduls have this office and this use, I intent not now to speak of, let it be what it will, 'tis too inconsiderable a matter to make any more words of it.  
I confess, that the dangerous experiments which Vipers have, made them so displeasing to me, and even so odious, that I resolved not at all to meddle any more with them; but that I was tempted thereto by a great desire I had experimentally to learn, whether the volatile Salt of Vipers, Chemically prepared, were endowed with that present and infallible virtue of curing the bitings of Vipers, as the said Writers affirm. For my Genius keeps me from much trusting to those things, that have not been made out to me by Experiment; although I do not presently reject them as false before Experiment, but rather being desirous to know whether they be true, I put them to trial: But neither do I acquiesce in one or a few experiments, but I love to see more and more, being ever apprehensive lest I should be deceived; as it often hath happened to me, when I have been ready to confide in one hasty experiment. And to say truth in the month of June there wanted not much but that I had imposed upon myself in the trial of an experiment, which I am going to relate to you, and which done I shall ease you of further trouble.  
Having read them in the Book of the New Experiments, that the Head of a Viper, being eaten of an animal, bitten by another Viper, did certainly cure the wound; and the thing being by me looked upon as very useful, excellent, and admirable, I had an eager desire to try it myself, that I might speak of it with more confidence, although those learned men had made these two following experiments of it, viz. pag. 120. We had also a desire to find whether a Viper being eaten by an animal, which she had bitten before, would be cured of that biting. We therefore caused to be slightly broiled the head of a Viper, which had on it a part of the neck, newly severed from the body; and we caused a Dog to be thrice bitten at the ear, by a well enraged Viper, in such a manner that the blood came out at the three pricked places. We soon cast before him the head and neck; broiled, and yet hot. The Dog, that was hungry, and felt not so soon the effects of the bitings, immediately seized on the head, bruised it between his teeth, and swallowed it down. After which we stayed a pretty while to see, whether the three bitings would prevail over the devoured head and neck▪ but the Dog was free, except some blewness and a little Tumour he had at the places bitten, but which little by little vanished in three or four days. We made also a Dog to be bitten three times in the same place, and without broiling the head of the same Viper that had bit him, we cast it before him, hoping that he would eat it, because he had not eaten any thing for many hours before; but the Dog would not touch it. Upon that we bruised and stamped that head in a mortar, and so crammed it down the Dog's throat, rubbing also the bitten places with the blood of the same Viper; which done, we expected the success, which was▪ that this head, raw and bruised, and if you will, assisted by the blood of the Viper, being applied to the part bitten, had produced the same effects with the former, which had been slightly broiled; in regard that this Dog was safe, excepting those inconveniencies the former suffered, and was after that as sound as if he had never been bitten. If these two Experiments had been made before that Gentleman, above discoursed of, was bitten by a Viper, we should have been in much less anxiety for his preservation.  
And a little before (pag. 119.) they had said: We have tried, that having caused to be bitten at the thickest place of the ear, by a sufficiently vexed Viper, a young Cat, very lean, that had but just before eaten the Eggs, the Matrix, and all the Guts of a Viper; the biting had almost no effect, and there appeared nothing but a very little swelling, and a very inconsiderable lividness in the part bitten.  
And pag. 154. It is very certain, that the Head of a Viper, broiled and swallowed, healeth the biting of that Animal. The Heart and the Liver may do the same. Reason and Experience have confirmed it; and therefore in an urgent occasion these parts may be very beneficially employed.  
And pag. 156. We believe, that the Liver swallowed is capable to heal the biting of a Viper, like the heart, flesh and other parts, of which we have spoken; and that it may much facilitate the delivery of Women with Child, as doth the Liver of Eeles.  
Hereupon I resolved to imitate those Gentlemen, and having given a Viper's head half boiled to a chained young Dog, I caused him immediately to be bitten by an other Viper in the right ear, but the Dog died not, nor did he appear to me to have any other inconvenience than that he stood as 'twere amazed, and looking grim, and melancholy, for four or five hours' space. I soon reiterated the same Experiment upon another Dog, which having been forced to swallow the head of a Viper, raw and bruised in a Mortar, gave no sign of any great poison, and had very little and almost no ill ensuing. Whence I was ready to reckon this Experiment among things proved and true, when a doubt coming into my mind, obliged me to cause two other young Dogs to be bitten in their ears, who although they had not eaten the counter-poison of a Viper's head, yet died not. Whence the suspicion being increased in me, I caused to be brought me the raw head of a Viper, and crammed it into the throat of a young Pullet, and then had its left thigh bitten by a Viper; whereupon it presently fell to the ground, and in a little more than the eight part of an hour died. Whence the suspicion growing still greater, about ten a clock in the morning I made a Capon to eat two raw heads of Vipers, and afterwards about twelve a clock I made him swallow two others, and without losing any time▪ I caused him to be once bitten by a Viper in the thigh, and the Capon immediately died, without finding any good in the four swallowed heads. The next day I prepared for two young Dogs a dish of Viper-heads parboiled, but they would not eat them, and we were forced to cramm them down: Soon after, the lesser of the two Dogs was bitten in the thigh near the groin, and the bigger in the tongue; and they both died. And in the like manner died eight Chickens, two Kitlings, two young Hares, and six Turtle-Doves, likewise bitten by Vipers, and Physiqued not only by their heads, both raw and boiled, but also having their wounds washed with the Viper-blood. And I remember, that I caused those 6 Turtle-Doves to be bitten not by the heads of live Vipers, but by those of dead ones, and such as had died two days before. Moreover, I continued for three days successively to cram two such other Doves with Viper-slesh, and gave them no other drink then the broth of that flesh; and yet they could not escape death, being bitten by a Viper.  
Whence I am inclined to believe, that in Tuscany the flesh of Vipers is no help or remedy, at least no considerable one, to Animals bitten by Vipers. Mean while I refer myself to the Learning, Experience, and Authority of those noble persons, to whom I do most willingly submit this or any other opinion of mine, and with whom I would never entertain a controversy. For I should apprehend lest it might befall me, what Marcus Tullius was wont to say of Cato, viz. That it was not less troublesome to him to answer to the authority of Cato, then to his strongest arguments.  
For the rest, I earnestly entreat you, Sirs, that you would pardon the rudeness of this my Letter, sufficiently appearing to have been written by a person full of business, rather than enjoying leisure; and that you would please only to regard the naked truth, which without any passion I did undertake to relate.   

A CONTINUATION Of the NEW EXPERIMENTS CONCERNING VIPERS: TOGETHER With a Discourse touching their Poison: By way of Reply, to a Letter written by Signior FRANCISCO REDI, to Messieurs BOURDELOT and MORUS; Printed at Florence, 1670.  
By MOYSE CHARAS. Englished out of French.  
LONDON, Printed by T. R. for John Martin Printer to the Royal Society, at the Bell in S. Paul's Churchyard, 1673.   

A CONTINUATION Of the NEW EXPERIMENTS CONCERNING VIPERS.  
Finished in the Press at Paris, August 4. 1671.  
I Believed, I had sufficiently established my opinion touching the Poison of Vipers by abundance of Experiments, supported by Reasons, heretofore made public: But there hath since appeared at Paris a Letter of Signior Redi, in which he opposes my sentiments: And he being a person, whose merit hath acquired him a great reputation among the Learned, that Letter of his hath not been without making some impression in the minds of many, and in some even of those, that had relished my opinion, in favour of which they seemed to have already declared themselves.  
I might indeed have defended myself as to that which is against me in that Letter, soon after it appeared; having reasons strong and numerous enough to maintain and justify all I had advanced in my writing: But I thought it better to defer it till Spring, to the end that after I should have made New Experiments, and the more assured myself of all, I might, by a renewed knowledge of the truth, afterwards the better persuade the public thereof. It will therefore appear by this Sequel of Experiments, here set down, that I am so far from changing my Opinion, that I have reason to be more strongly than ever confirmed in what I embraced at first.  
I do herewith sincerely declare, that when I published my book, my chief aim was, faithfully to relate all the truths I had discovered, and not to offend Signior Redi, whom I exceedingly esteem and honour for his rare Talents, and whose friendship I hope to have a share in; so far was I from pretending to do any thing that might make him write against my Book, or from foreseeing that ever I should have occasion to labour to defend myself against him: Which yet I since found otherwise, by the Letter he hath written against me, and even without honouring me with a Copy of it, wherewith he hath gratified many persons at Paris and elsewhere, even after I had had the advantage of some Letterary Commerce with him, as I might easily justify.  
I can besides protest, that when I resolved to contradict certain points of his first Letter, it was in a manner against my will, and because I could not at all dispense with it, except I would have baffled my senses, and that light I saw myself, together with a great number of witnesses. I can also assure, that I should now be very ready to un-say what I have affirmed upon this subject, and to agree with him, if I were not altogether persuaded of the contrary in the main things he hath written against my Sentiments.  
After these Protestations, being well assured as well by Reason, as by many new Experiments newly made, that I have asserted nothing but what is true; I found▪ myself indispensably obliged to maintain it, and to render a good office to the public, by endeavouring to show that 'tis very difficult reasonably to oppose any thing to the contrary.  
The difference between Signior Redi and me consists chiefly in this, That he Pretends, the Jellow Liquor contained in the Vesicles of the Gums of Vipers, to be the only and true seat of their Poison; That this juice is not venomous when taken at the mouth, but that it is so when let into the wounds made by a Viper whilst she is alive, and even in those, which she may be forced to make several days after she is dead, provided that yellow liquor do intervene; That the same liquor drawn from a live Viper, as well as that of a dead one, is always venomous if let into wounds, and mingled with the blood of the Animal wounded, whether it be used when liquid, or after it is dried and reduced to powder; and that it generally kills all kind of Animals into the wounds of which it shall have been intromitted.  
But I, who of all these points can admit of none but that of the innocence of the yellow liquor when taken at the mouth, and opposing myself to all the rest; do say, That the Poison of a Viper is no where but in her enraged Spirits; that the yellow juice as well of a live Viper, and even a vexed one, as of one that is either newly dead, or hath been so for several days, contains in it no poison at all, neither in the biting, nor taken inwardly, nor put into wounds, nor mingled with the blood, nor any other way wherein it may be used; that it kills nor infects any kind of animals; and that it is nothing but a mere and innocent Saliva.  
The question must principally be decided by matter of Fact; though it may also be cleared by very pertinent reasons. I am far from accusing Signior Reds of unfaithfuless in his Experiments; though they were not made in public as mine, and that some thing might be said as to the formalities of the biting, and the using of the yellow liquor: His reputation is too well grounded to be blamed; and this is the consideration which troubles me most. Mean time I see the contrary to what he hath advanced against my Book; and the truths which I there oppose are so clearly seen in my Experiments first and last, as well in those I have made only in the presence of some curious persons, as in those I have lately made in public, and before a great number of Physicians and other persons very intelligent in these matters. So that I can no● ought any longer to hide those truths, which are the chief inducement of writing this discourse.  
We need not wonder that Signior Redi, having made all his Experiments by order and at the expense of so great a Prince, who is as curious as he is Munificent, had Vipers and all sorts of Animals in far greater number than I had; I, who did all from myself, at my own charges, and with a mere desire to discern truth from falsehood. Nor do I think, I was obliged to multiply expenses when the truth was found sufficiently cleared up, and all the bystanders acknowledged, that I had made sufficient trials for every Experiment. For since he hath contented himself with having made some of the yellow liquor to be swallowed by one only Man, one only Duck, one only Kid, thence to know and to assure himself of its innocence when swallowed, without making a greater number of Experiments; He must not blame me for having candidly bounded my curiosity, after I had in divers things made many more Experiments, than he mentions he hath made upon this subject; as appears by what he writeth p. 17, & 18. of his first Letter. I find therefore, that he hath no great cause to complain of me (as he doth, under the name of those Illustrious Authors, to whom he ascribes my Book in his Letter) for not having vouchsafed to make Experiments enough to confirm the truth of the Observations about Vipers, contained in his first Letter of 1664. He had not, I say, great cause to speak of it after such a manner, since I did do so but in imitation of him, and because he had in the same Letter advanced and assured particulars, which required not I should make more trials than those I have described in my Book: Although I can assure to have made more than I have recited. He knows very well, that about the end of pag. 23. of his first Letter he used these words.  
Equel veleno shizza tutto fuora, se non al primo, almeno al secondo morso; si che il terzo (epiù volte l'ho esperimentato) non è velenoso: That is, And that poison issues all out, if not at the first, at least at the second biting; so that the third (which I have often experimented) is not venomous.  
And if, because of the respect I bear to the writings of a person of so high a reputation, I thought among divers other Experiments, that having made one and the same Viper, every time vexed, to bite five several Pigeons, which all died, and even the last of them sooner than the rest, I might stop there; I think Signor Redi hath nothing to reproach me with. He had assured in his first Letter, and assures the same in his latter, That all the poison did lodge in the yellow liquor, and that this poison was all exhausted if not at the first, yet at least at the second biting, and that he had often experimented that the third was no more venomous: So that, if I was persuaded, that all the yellow Liquor must be come out by the second biting made upon the second Pigeon, and if, after that, I have seen die three other Pigeons by the fresh bitings of the same Viper that had bitten the two first; I do not think that Sign. Redi hath right to accuse me for not having done enough: He might rather have done me that justice as to acknowledge, that I had done more then enough to maintain my Reflections, and that I was obliged from that time to seek the poison elsewhere then in the yellow liquor, in regard it did no longer intervene, according to him, in the three last bitings, and that the three last Pigeons were as soon, yea sooner, dead then the two first, of the death of which he could charge the yellow liquor. If I could not find, no more than Sign. Redi, in all the body of the Viper, any other visible or palpable part that was venomous, and that might justly be declared to be the seat of the poison, and the true cause of the death which ensued upon the three last bitings; he must not wonder, if I have sought and found it in the vexed Spirits, and if I have grounded myself upon the best evidence, I could get from Experiments and Reason.  
But since the chief motive of my trials hath been the desire of exactly knowing the Truth concerning those matters; having seen that Sign. Redi, pag. 31. of his last Letter hath desired I would make new experiments after his Objections against me: To be the more assured of all, I have been willing to give him that satisfaction, in giving it to myself. For, in the month of May last, in the Chemical Laboratory of the Royal Garden, in the presence of two or three hundred by standers, both Physicians and others, capable to judge of it, and worthy to be credited; from amongst many live Vipers, sent me out of Dauphine, and divers parts of Poitou, I chose a great Femal-Viper, that was lusty enough notwithstanding the great way she came, and having opened her jaws, I very carefully cleared and squeezed out of them at several repetitions, all the yellow liquor contained in the bags of her gums, and that also which might be diffused about the neighbouring parts, with a fine piece of linen cloth wound about the handle of a pen knife: Which done, I took the same Viper with Pincers about hér neck, and angered her in making her to fasten her teeth into the end of her tail, and in pressing from time to time her neck with those Pincers; and immediately after I presented to her five Pigeons and two Pullet's one after another, to bite them in the most fleshy part of their Chest, having irritated her every time of her biting. I purposely wounded also six Pigeons and Pullet's in divers places, in the presence of all the company, and let into the wounds some drops of the yellow liquor, drawn from the Vesicles of newly enraged Vipers. I laid both sorts a part; and the company parted about an hour after, before which time, five of the Pigeons and Pullet's, that had been bitten, were dead, and the two remaining died about an hour after; but the Pigeons and Pullet's, which I had wounded, and in whose wounds I had put in some of the said juice, ailed nothing, but that there appeared some lividness, at the place wounded, and such an one as might have been there from the sole wounding them, and without any concurrence of that liquor. Two days after, I showed the company the same wounded Pullet's and the same Pigeons, which were very well, and had their wounds almost perfectly healed up, only there remained a little blewness about the wounded parts. I would then have wounded the same animals again in other places, and intromitted fresh yellow liquor: some also of the bystanders proposed to let into one of these creatures some of this yellow liquor by that way of Transfusion, that hath lately been made in divers parts of Europe, of some stranger blood into the veins of men, that so this juice being mingled with the blood by the ordinary circulation, it might be able to discover what ever it could do. I readily complied with their motion, whereupon the intromission of this liquor was attempted upon one of the same Pigeons that had been wounded two days before. One Physician and two Surgeons did the work one after another, in making both the incision and the ligature of the most discernible vessels of the right wing: But they let the Pigeon lose so much blood, that it died soon after. Seeing this, I said, that the Pigeon died only from the loss of its blood, and not from the letting in of the yellow liquor; and that it would be necessary, one only Chirurgeon of the Company should make a new operation upon another of the same Animals, that had been wounded 2 days before, and upon whom that yellow Juice had also been tried. The Operation was made accordingly at the same time upon a Pullet, which did not only escape again, but was seen the next day and the following days by the whole company to be very well; as were also the other animals that had been wounded again at the same time, and received of the yellow liquor, though without the way of transfusion. Yet true it is, that one of the Pigeons, that had been the second time wounded, was found dead some time after its being wounded, in a close earthen Furnace, very hot, and standing close by such another, where I than distilled some spirit and oil of Tobacco, and the death of which ought to be imputed to the piercing vapours of this distillation, or to the excessive heat of the Furnace in which it had been shut up, which was found so hot, that the heat of it could not be endured by one's hand; besides that being closed, almost no air could enter.  
Which being thus passed, yet forasmuch as the reputation of Sign. Redi had acquired him much esteem and favour from many persons in Paris, I perceived some of the company yet inclined to doubt, whether this yellow Juice were always innocent. Whereupon, having by me 4 Dogs of different bigness, I pressed those that seemed most to doubt, that they would transfuse or cause to be transfused some of that reputed poisonous liquor into all those Dogs, or at least into one or other of them; but how instant soever I was, no body would undertake it. It was alleged, that those Animals were too Robust to Succumb under such an operation, since the Pullet, that had endured it, and twice felt the yellow liquor, had escaped as well as the other Animals, that had been wounded again at the same time with it, and that had also received into them some of that liquor. Which obliged me to protest, it was not my fault that it was not experimented a fresh, and to pray the company to take the refusal of those persons for an acknowledgement of the innocence of the yellow liquor.  
But not being satisfied herewith, I referred the matter to the next day, and promised to have ready new Animals, of a lesser size than those Dogs; the more amply to verify the innoxiousness of that Juice by new intromissions thereof into wounds.  
I had then prepared six Pigeons, and two Carlings; and engaged a person whom I knew most favourable to Signior Redi, to make himself the incision, and intromit the yellow liquor as he should think best. He made such wounds as he pleased, and he did even sever the skin of the flesh round about the wounds he had made, and so far, that I could not hold to tell him smiling, he did more than Signior Redi himself said in his Letters he had done; and added, Boni esse pastoris tondere, non de glubere, A good Shepherd did Sheer, not Flay his Sheep.  
One of the Catlings was bitten in the Cartilagineous part of the Ear, without any appearance of blood at the place of the biting; and it escaped. The other, which was much less, and a very noted one by the blackness of its colour and by having her ears cut off, was purposely wounded on the upper part of her neck behind, and also at the lower bone of the hinder part of the head; its skin alsowas separated from the flesh round about the wound, and on both sides, almost as far as to the fore part of the neck: And then as much of the yellow liquor as they would was put into both sides as well as into the wound. This Cat held down her head, by reason doubtless of the pain she endured by having in a manner been flayed alive; feeling also some pain in two other places, where she had been wounded and flayed. Some of the bystanders began already to mutter, and said, I should be cast, and the Cat would certainly die; yet notwithstanding the Cat did not die, though she was very little and taken out from under her dam; and she was showed to the company 24 hours after, sound and safe, although she had neither sucked nor eaten any thing all that time. And 'tis remarkable enough, that this very Cat, having been returned to a Friar to whom she belonged, and being grown big, hath yet to this day the hind-part of her skull unclosed at the place of her wound; and notwithstanding all that, & the falling off of some flesh and skin, that were severed from the places where she was flayed, she is very lively and full of play, and very divertising mimic gestures.  
The six latter Pigeons, that had been wounded at the same time, and received of the yellow liquor, were likewise produced; and they were yet kept five or six days with the other Pigeons and Pullet's that had been twice wounded before; among which was that also on which the transfusion had been imitated. At last they were killed, roasted, and eaten, in good company, of which were some of those that saw them wounded; and that found them very good and savoury meat.  
Amidst all those Experiments I omitted not to try, whether the heads of Vipers newly dead, having yet their necks on, with all their yellow liquor, would be able to kill Animals, by making them to be bitten by them. I tried it upon Pigeons and Pullet's, by thrusting the teeth into them as deep as I could. I employed also to the same purpose some whole Vipers, which I had found dead among the live ones in the barrils, and which abounded in the yellow liquor. But this was always without any inconvenience to the Animals bitten, so far was it from killing them.  
I here pass by many other Experiments made at my house, in the presence of several Physicians, that did all agree in making out the innocence of the yellow liquor, and in ascribing the poisonousness to the enraged spirits.  
Yet I must not leave here un-mentioned, what was done by three young Physicians, who being persuaded of the truth of my Experiments, as well concerning the innocence of the yellow liquor, as that of bitings made without the angered spirits, caused their fingers to be bitten, to strifes, by a dead Viper having yet all her yellow liquor, and that so deep, that the blood of it appeared to all: But they found no other inconvenience by it, but what they might have felt from prickings made by a needle.  
I had certainly made a far greater number of Experiments if I had not observed, that Sign. Redi himself had already made many for me, and for the maintaining of my Sentiments; and among others that of pag. 26. of his first Letter of Observations, where he saith,  
Si mori un pollastro morsicato, etc. That is, There died a Pullet bitten by a Viper, the points of whose teeth I had cut off; and out of whose vessicles I had squeezed out all that ill juice that it there.  
For, since by his own confession, there died a Pullet by having been bitten by a Viper, the points of whose teeth he had designedly cut off, and all whose yellow liquor (which he calls the ill juice, and will have to be the only seat of the poison) he had carefully pressed out of the vesicles of her Gums; He hath no more ground than I, to charge the death of the Pullet upon a liquor, which was there no more, nor upon the points of the teeth, which he had cut off. And he cannot avoid to accuse with me the vexed spirits of the Viper, and to fall into my opinion, viz, That the venom of the Viper is not a gross matter, but something invisible and spiritual.  
And to show again, that Signior Redi hath laboured, without being aware of it, to justify my Sentiment, and that at the same time he manifestly contradicts himself, by destroying in his last Letter his first Propositions, which is, That all the venom of the Viper issues at the first, or at least at the second biting, and that the third is venomous no more, as he assureth to have often experimented; to show that, I say, I shall allege the words of pag. 33, 34, and 35. of his last Letter, viz.  
Su'l principio di maggio scelsi una vipera, etc. That is, About the beginning of May I chose a Femal-Viper, one of the biggest and lustiest, and vexed her to bite ten Chickens, one after another, in the right thigh; of which the first, second and third died almost in an instant; the fourth seemed only to be sick; but the fifth and all the rest did not only not die, but were not at all sick; and yet every time the Viper did bite, I angered and madded her exceedingly. In the month of June I repeated the Experiment in five tame Ducks, bitten by one and the same Viper, which also immediately after bit three young Turtle-Doves. The first wounded died three hours after; the second-five hours after; the rest escaped. 'Tis true, that the first mentioned of the Turtles died, but not the other two. Of twelve Ringdoves at one time there died but four; but the next day of twelve others there died six. Of five Rabbits there died three; and of three Lambs the two last died; the first of them dying two hours after it had been biten.  
These several Experiments directly contrary to the first assertion of Signior Redi, were capable to perplex any other head but ●is. For first, he hath seen, that of ten bullets bitten one after another by one only Viper, the three first died suddenly, and the fourth was somewhat sick; He hath seen, that of five Ducks and of three Pigeons, bitten one after another by a single Viper, the two first Ducks died, as also one of the Pigeons, which had been bitten even after the five Ducks: He also saw once, that of twelve Pigeons bitten, four died; that another time of twelve there escaped but the moiety; and that of five Rabbits, likewise bitten, there were but two that evaded dying.  
I cannot but be amazed, that all these Experiments have not been able to change his opinion, or at least to suspend it. Nor do I doubt but that the number of Animals that d●ed would have been much greater, if the bitings had been made in other places but the legs. For, besides that they have their bones, nerves, and tendons, that are able to blunt the point of the teeth at the first biting; they have also their Muscles, which are very viscous, and therefore fail not to imbue the teeth of the biting Viper, thereby stopping in part their Pores, and even hindering them by that v●scosity from entering far in the ensuing bites, and I likewise doubt not, but that will come to pass more and more in the reiteration of their bitings. Nor do I wonder, that the Ducks did not die so soon as the Pullet's or Pigeons, nor that there died less of them; for, besides the reasons just now alleged, they have their skin, bones, and all parts much harder, and far more difficult to be pierced by the Viper's teeth, than those of Pigeons or Pullet's. Now I do not find any part mo●e proper to try divers bitings, than the fleshy part of the chest, which hath neither Nerves, nor Tendons, nor bones near, nor that Viscosity found in the Muscles of the legs.  
Mean time these Experiments made by Sign. Redi himself, must oblige him, as far as I can judge, to relinquish his first Assertion: And if he will persist to maintain, that the yellow liquor is the true seat of the poison, he must needs believe that liquor to be inexhaustible, and that always there succeeds some fresh, in all the bitings of a Viper; or, if he will abandon his opinion, and ascribe the poison no more to the yellow liquor, he must find out some other subject to assign it to, except he please to take mine, and to lodge it in the irritated spirits; in regard that he cannot find it in the yellow liquor, which is no more there, after the second biting (as himself assureth;) and which must yet more evidently be wanting there, when designedly he had with care taken it out of the bags of the gums of the Viper that bit the Pullet, and the bite of which was followed by the death of the Animal bitten.  
But if Sign. Redi should now be in an humour to alter his opinion, and to judge the yellow liquor to be necessary in all the bitings of a Viper (though that be an impossible thing;) his opinion would never be received by disinteressed persons, that have seen my first and last Experiments; among which persons there are some, even of the most able, who, having heretofore examined the Salival Glanduls upon the description I gave them of it after I had discovered them, did there observe also some small Lymphatic Vessels, more numerous than those that had first appeared to me; and who, having seen the last Letter of Sign. Redi, were willing to suspend their Judgement until the making of my new Trials, which have altogether confirmed them in my first opinion.  
For, not to speak of this, that in the presence of divers persons, even of the best quality, at several times and places, in divers assemblies, & even in the Conferences of the Abbot Bourdelot; I have swallowed some of the yellow liquor taken out of the bags of the gums of many live and enraged Vipers, without finding the least inconvenience from it, no more than the Viper-catcher of Sign. Redi: I can boldly assure all the world, that at no time, in no place, there ever died any animal of all those I have wounded, or seen wounded on purpose, and into the wounds of which that liquor hath been intromitted, although it had been drawn hot out of the Vesicles of the gums of Vipers exceedingly vexed; so far is it, that the Juice of dead Vipers was able to annoy any animal. I can also assure, that never any head of a dead Viper, whether the Animal were who●e, or that head only with its neck, and though it abounded with that yellow liquor, hath done any harm to man or any other Animal, bitten by it.  
The yellow liquor, which I swallowed in one of the conferences of the Abbot Bourdelot, puts me in mind of Letter, which M. Des Tapieres, a very curious, sincere and able Apothecary of Bourbon l' Archamband, had written to him, which was there read, and among other things did relate, That in the year 1630. he had taken a Viper, whose crooked teeth he had cut, and that he carried her in his bosom; and that after two or three days, a fancy taking him to approach her to his face, pressing her a little, she bit him in his lip, and thereby caused great pain to him; whereupon he flung her to the ground and in his anger crushed her in pieces; that his lip and face swelled; that a Ligature was made upon him; that Treacle was given him, and some of it applied to the bite; that at the place of the wound there appeared a little bladder, whence issued two or three drops of liquor of a dark yellow colour, and that his face remained very pale for a month.  
If my opinion be asked about this Experiment, I declare that there is nothing in it, which I ought not to believe; and I add also, that there happened nothing in it, which agrees not with the principles by me established and maintained. For, although the great teeth of that Viper had been cut, which might have gone further, and mingled the enraged spirits of the Viper with the blood of M. Tapieres; yet they had not cut the point of the small teeth, which I showed in the same conference together with the other neighbouring parts in the teeth of a live Viper, sent to Monsieur Bourdelot by the same Apothecary that had been bitten: of which small teeth I have heretofore given the description and figure, as well as that of the upper and lower Jaws, in which they are fastened, as may be seen in my Anatomy of Vipers, in the Section of the teeth, and the third Cut of that Pook. For, although those little teeth have not the length nor thickness of the great ones; yet they have the same shape and the same matter; for they are bony, crooked, transparent, and very sharp; so that the vexed spirits may pass into them as into small Funnels, and through their Pores, as they do through those of the bigger ones: But they cannot go very deep, because their smallness permits them not to carry their openings as far as into the flesh; and all they can do, is, to open the skin. Now to reason upon the accidents that befell M. Des Trapieres by this bite, as they are set down in his Letter; I see nothing in them that is not very natural, and very credible. For, although the angered Spirits had entered by the openings made by the small teeth; yet they could not penetrate the flesh, nor mingle with the blood, because those apertures were not deep enough, and they could do no more but to make their effort 'twixt the flesh and skin; whence followed the swelling of the lip and face, and the impression of the pale colour, which appeared there during a month; which accidents might at first have been easily prevented by one only dose of the volatile Salt of Vipers, which would have made the enraged Spirits to transpire, that lodged between the flesh and the skin, and could find no entry to pass further. As to the little bladder, which was form at the place of the bite, and the two or three drops of dark liquor that issued afterwards, that was nothing but a little serous moisture that had been gathered there from the neighbouring parts, and that had been caused by the compression of the Ligature, and by the bruising made by the teeth and Jaws at the time of the biting, and without any intervention of the yellow liquor, which besides its innocence, could not have entered through such small apertures.  
After so many Experiments, and upon so many Reflections which I have made, as well on the yellow liquor, as on the irritated spirits of Vipers, I cannot comprehend, how the Animals of Sign. Redi could die all and without any exception by the intromission of the yellow liquor into the wounds, he had made in them, and by the biting of heads severed, or by that of entire Vipers that had been dead several days. I have too many experiments to the contrary, and too many witnesses, to put it out of doubt, and to fix me in my first opinion.  
But, to the end that among the Truths by me advanced, and consisting in matter of fact, the public may find wherewith to be satisfied; I thought myself obliged to explain my sense upon these matters, and to form to myself the Objections, that may be made against me.  
I say therefore concerning the Tellow Liquor, That nothing can act from itself, but according to its nature, the disposition of the matter of which it is composed, and the force of its activity. For example, you will not find in River Water, the taste, strength, nor particles that are found in Wine, nor will that inebriate like this: it hath not the acrimony nor penetrancy of Urine, neither the colour not bitterness of Gall: The Spirit of Wine, that is freed from the aqueous parts, which hindered the Wine from producing the effects it was capable of, is much more subtle and strong, than the same wine whence it hath been drawn: The Volatile Salt of Wine hath quite another penetrating force than the Urine which contained it before its sublimation: And not to go from my subject; the volatile Salt of Vipers is very different from the flesh and bones of them, whence it hath been extracted; and, though in small quantity, it will work more in a moment as well by its odour as its piercing virtue, than ten times as much of that matter, whence it hath been drawn, could effect in many hours: The bileous, sharp, salt and spirituous serosity, that is often formed in our bodies, will suddenly produce inflammations in the eyes, tumours in the cheeks, gums, throat, and many other parts, as also Pustuls, St. Anthony fire, and the Gangrene itself; and all that it does by the composition of its parts, and the force of its activity; whereas the thick and viscous Phlegm will do no such thing, but chargeth nature only by its weight, cold, and tenacity: This Phlegm, I say, will ever be incapable of working with quickness, and it cannot produce any effect out very slowly, and in proportion to its power, which is extremely confined.  
So then, it is not the nature of the yellow liquor, to pass swiftly to remote parts, and there to act with vigour and violence; which is observed in the poison of a Viper. I say, that a tough, viscous, and in a manner insipid Saliva, cannot make any great progress in a moment. I affirm besides, that 'tis impossible, it should corporally enter into the holes made by the teeth, which are very small and almost invisible, and that it should also pass through the cavities of the teeth, and much less through their Pores, if any would have them pass that way. I say further, that although the teeth of a Viper should be all over imbued with that Juice at the time of her biting; the skin of the Animal bitten, and the flesh itself, if need were, would keep it out of the bitten place, and hinder it from entering there; That though it should be able to enter, it must have a fit place to receive it, a great passage to go through, and a long time to arrive to the parts remote; I say also, that though it were arrived there, (if that were possible,) it could never act beyond the forces, which nature hath restrained it to.  
Besides, if this yellow liquor were capable of any considerable operation, it would not fail to discover it either in whole or in part, when 'tis swallowed and got into the stomach; where the place, the heat, and all things would seem to concur either to make it ferment, if its matter were disposed for it, or to reduce its power into action: For, by passing out of the stomach into the intestins it would infect the Chyle, and make of it a poison, which would be carried jointly with it through the milky vessels, and through the Thoracique Ductus's, so happily discovered by the illustrious M. Pecquet, to descend into the Heart with the blood, the which is the matter, on which the poison of Vipers does so particularly exert its dominion. And this way is much more easy and large, than that of the opening, made by the teeth, by which this juice cannot so much as enter. I say this further, that, if it were such as Sign. Redi makes it to be, it would, being taken at the mouth and let down into the stomach, impress upon the places of its passage, and those of its stay, some mark or other of its power, especially if it did contain any Arsenical Salts, which would not fail, soon to manifest themselves either by their taste or by some other effects: And yet all those that shall taste or swallow this yellow liquor, shall never perceive any malignity whether great or small, neither in the mouth, nor in the stomach, nor elsewhere. I conclude therefore from all these considerations, that this juice contains in it no part at all, that is able to dissolve, or coagulate, or discompose any part of our body; & that it hath not any quality, manifest or occult, to show that 'tis capable of doing so.  
I add moreover, that this juice, as flat and salivous as it is, is always found so yellow in all parts of France, that it can hardly be less coloured than 'tis in Italy; and that they both must have altogether alike qualities, or, at least, very near such. And it would be to no purpose, to allege in favour of Sign. Redi, that the diversity of places and climate, or that of aliments might be able to change the nature of Vipers, and cause that manifest difference, there is between his Experiments and mine. For, although some diversity may be observed in other things, there can be found none in this; and if there could be some difference, it cannot be that the nature of the yellow juice, and that of the Spirits should be quite changed; since we find in France the same marks in that liquor, which Sign. Redi hath found and described in that of Italy, and since our Vipers, without any intervention of that juice, do kill as nimbly as his can do.  
But I think it would be much, if in the yellow liquor, or in the enraged spirits, there could be observed any small degree of quality, stronger or weaker in Italy than in France. For, I have by a great number of experiments made it out, that all the Vipers of France, though taken in very different places, and often such as are six score Leagues distant from one another, have their poison altogether alike, and do kill equally. Whence I infer, that the difference of the Vipers of Italy and France, cannot be considerable; since Dauphiné, which is a Province in France that furnisheth us with many of them, and is very mountainous as well as Italy, borders upon Picmont, which is the beginning of Italy; and that the same Dauphiné, abounds in Vipers in its utmost extremity; and since also all Vipers, we get from thence, have their yellow liquor always very innocent, though high coloured. And I can truly say, that those Vipers, that have served me most both in my first and last experiments, were most of them sent me out of Dauphiné, and that I was willing to make use of such, as being commonly bigger than most of those that were sent me out of Poictou; that, at least, which served me to bite the five first Pigeons, which I spoke of in my first Experiments; and that which bit the seven last Pullet's and Pigeon, were of those of Dauphiné, and even of the bigger sort that could be procured.  
And it would have been to no purpose to have used any tooth of a Viper severed from the head, and much less to wipe it dry with some bread crumbs, in hopes it should kill any Animal by pricking it therewith; seeing the teeth, that had of the yellow liquor upon them, without being separated from the dead heads, were not able to do any harm, no not those of live ones, without the concurrence of the enraged spirits. And if sometimes I have made use of bread-crums, sometimes of a sine linen rag, to wipe away all the yellow liquor of the vesicles, that was never but in live Vipers; to show, that it was not that liquor which did kill, but the vexed Spirits only, entering by means of the biting.  
We are not to imagine neither, that a Viper teareth by biting, unless having made her to thrust her teeth into the flesh of some animal, you do immediately after draw her away by the rest of her body: We are not, I say, to pretend, that a Viper doth, by biting of her own accord, make any great opening, at which the yellow liquor is able to enter. For, she doth no more but thrust in her teeth far enough, and presently draw them out again, with as much ease as a Cat draws out his claws when he will. Besides, you cannot perceive but two very little holes, which do also seem as 'twere closed again by the flesh, and which would hardly be discerned, if the pain of the bite, or the accidents ensuing, did not oblige us to look very narrowly to it.  
We also never see, that the poison fastens itself to the part bitten, nor that the evil begins by a mortification, or by a gangrene there. For, if that were so, and if the venom did lodge at the entry, it would be much more easy to master it. I know also by many Experiments, that the poison never stays at the place where it enters, but insinuates itself very nimbly into the Veins, to mingle with the blood; especially if the bite hath opened for it a passage free enough to arrive there. I know, that there it produces afterwards those troublesome accidents, which ensue upon the biting; and that lastly it causeth death, if it be not prevented by a quick relief. Which clearly shows, that a poison of this nature must needs have dispositions to penetrate, very differing from those that appear in a yellow liquor, that is incapable of all sudden motion and operation.  
It would also prove an useless labour, to suck at the place of the biting, in hopes of getting out from thence a Juice, which could not enter there. And though I do not disprove this way of succours on such occasion; yet I know, that all what the sucking can do, is, to fetch out again part of the enraged spirits, that had entered by the openings of the bite. I know also, that a specifique remedy, taken at the mouth, is far better.  
I would be in vain, to object unto me the example of the seed of Animals, which, notwithstanding its viscosity, serves daily to propagate that Species which produces it; and that it could in like manner come to pass in the yellow liquor to convey the venom in the biting. For besides that the seed is the purest and most elaborat part which an animal can produce; it is also accompanied with store of Spirits; and there needs, besides, the concurrence of many other means as well to introduce and to receive it, as to form and perfect the Foetus: There is moreover necessary an assistance of abundance of spirits from the mother's side; a juice proportionate and proper for its nourishment and increase, and a sufficient time for the same. Whereas the yellow liquor, that can pass for nothing but a juice excreted out of the Salival Glanduls, after it had been sent thither from the brain and the neighbouring parts, and that is destitute of spirits and of all disposition to act; wants also a passage sufficient to intromit it, and a place proper to lodge in. And if you should grant it an entry, and a place to sojourn in; it must have a much longer time than the seed, of which I was speaking. But with all this time and all the other circumstances, it would still be incapable of working any thing at all perfect, and perish of itself; without any remarkable production.  
If any should say, That this yellow liquor may have spirits proper and proportionate to its nature, and that they are not wanting to make the poison work at the moment of the biting; but that, being drawn out of the vesicles, and exposed to the Air, those spirits are dissipated, and thereby render it incapable of all action: I answer, That, without staying upon what I have amply made out of its innocence in all kind of uses, Signior Redi himself contradicts it, as I have mentioned above; since he pretends, that the Juice even of such Vipers as have been dead for several days, & that is dried to boot, ceaseth not to insinuate its venom without any intervention of spirits, when it is put into wounds. But, besides all that, many Experiments have evinced to me, that death follows the biting without any intervention of the yellow liquor, and then when it hath been perfectly wiped away. Moreover, it is well known, that 'tis the nature of spirits, to be in motion, to fasten themselves to, and to follow the parts that have most of them, as for example, the blood. It is also to be noted, that the spirits, that do insinuate the poison, are not of the nature of those that follow the ordinary motion of the blood of the animal; that they do not join themselves to it, as those; and that neither of them have any union with the yellow liquor; which is but a mere excrement: But that the Spirits, I speak of, do form themselves in the moment that the Viper conceives the Idea of revenging herself; and they need not the embarasment of such a dull and viscous juice, which is not qualified to follow them, nor to pass through the imperceptible pores of the teeth, which the spirits only can penetrate, no more than they can any ways enter through the holes, which the teeth have made. In a word; the nature of a gross, tough and viscous juice is not, to act, penetrate, and be wiftly carried to the most remote parts of the body; but that belongs to spirituous substances, to go and come where gross corporal ones cannot. These are the only spirits, that can subvert the whole Oeconomy of the body; they are they, that disturb the circulation of the blood, and that corrupt it; they are they, that stop the natural and animal spirits, and hinder them from passing to the parts of the body as they were wont to do; and lastly, 'tis by the let of them, that the death of the Animal usually ensueth the biting.  
As to what may be objected, that 'tis very difficult, so exactly to evacuate the yellow liquor, that there remain none at all; and that it may very well come to pass, that a little of it intervenes in all bitings: I answer, that besides that this is also against the opinion of Sign. Redi, and which he hath renounced in his first Assertion; the Salival Glanduls, though many in number, yet are too small and have too little capacity to contain juice enough to furnish for that purpose; and that that cannot be expected but from great animals, that have those Salival glanduls and the other parts far bigger: And though it were possible, they should sufficiently furnish, I do maintain, that the impossibility of intromitting that juice, and it's evinced innocence, aught to suffice for confuting this Objection.  
Yet this I shall here say in favour of Sign. Redi, That I doubt not but that this yellow liquor, as Salivous and Excrementitious as it is, contains its Volatile Salt, as well as all the other parts of a Viper, and all the parts of Animals, and even all their excrements, and that consequently it is to be reputed spirituous. But then, besides that these spirituous substances are never hurtful, they are yet too intimately mixed and locked in with their matter, and they cannot produce their effects without being separated from it; which cannot be but by a violent heat, and in vessels fit for it. I say therefore, that by art there may be extracted a true Volatile Salt out of this yellow liquor, & even without any addition or mixture of other matter; which may be proved to be of the same nature with that of the other parts of a Viper; and that 'tis so far from being able to work like poison, that 'tis very proper and effectual to master all the ill accidents, which the by't of a Viper may cause; of which I do accuse the enraged spirits alone. Since therefore Sign. Redi hath dried and laid aside the yellow liquor of two hundred and fifty Vipers, and may easily obtain much more of it; 'tis in his power to extract such a salt out of it, when he pleaseth, to verify what I was just now saying: And if, to save himself that labour, by reason of his other important occupations, he shall please to send me a competent quantity thereof, I do with all my heart offer myself to prepare it for him, thereby to let him see not only the innocence of this juice, but also the great benefit, that is hid in it.  
Concerning the Bilious Breath of a Viper, that may be charged to intervene with this yellow liquor, and to envenom it; I am of opinion, that that is nothing but a disguise of the enraged spirits. I assert, That the true Breath of a Viper is ever innocent, how bilious soever it be represented; that there issues not any ill scent out of her throat, nor out of her guts, nor from the parts made to void the excrements; That Vipers among other marks are in this different from Snakes, that these have their excrements and the parts containing them very fetide and of a smell of stinking Urine; whereas you cannot perceive any ill smell in any part of a Viper; that the Spirits which carry the venom are quite another thing than the breath coming from the Lungs; that those spirits have no union nor correspondence with the Bilious humour; that they are not form but at the instant of the irritation; and lastly, that they need no such thing as an excrementitious and useless liquor, pretended to intervene, fit for nothing but to guard the passage of the place, through which the vexed spirits have entered.  
But the better to show the impossibility of the intervention of this breath, and to make it appear, that it never contributes any thing to the poison; you may take notice, that a Viper's head cut off, separate from the Lungs and all communication with the Gall, and incapable to yield any breath, and deprived even of all that yellow liquor; yet fails not to kill by its biting as long as 'tis alive, if the animal have been provoked; just as would come to pass, if a bite were made by the head of a Viper that is whole and alive, if no remedy were applied.  
Touching the Communication, that may also be pretended to be between the bladder of Gall and the yellow liquor, by reason of some resemblance of colour; I say, that, besides that my Sentiments in these matters are very conform to those of Sign. Redi; that we have both of us justified the innocence of the juice contained in the Bladder of Gall; that we have denied, there is any vessel carrying this better juice into the vesicles of the gums, to make that yellow liquor which is found there: and lastly, that we have unanimously contradicted the errors of the Ancients about this pretended channel; besides this; I say, the truth of what we have affirmed is very easy to prove, by tasting the yellow liquor of the Gall, which is very bitter and very sharp, though very innocent, and by comparing it with that of the vesicles of the Gums, which is very flat, though equally innocent. The same may be yet better made out by dissecting one or more Vipers; where, no more than in Serpents and all other animals, you will never find any vessel, that carries▪ this bile of the Bladder of Gall to the Gums; and you will there see nothing but veins and arteries filled With true blood. Of this there will be no doubt, if you please only to taste it; for you will find nothing but the ordinary taste of blood. To be yet more assured of it, you may taste all that runs out of the body of a Viper when the head is severed from her; for you shall find no bitterness at all, nor other taste but that of blood. And besides, having amply verified, that the yellow liquor comes from the Salival glanduls alone, and having given a very exact description of them; I think it needless to say any more of it, what ever the Ancients may have written, or the Moderns may say of that subject.  
To come now to the enraged Spirits of a Viper, which I do assure to be the true and only seat of the poison; methinks Sign. Redi hath no reason to oppose my opinion, when I do interess in it the imagination of the Viper, or her Idea of revenge, for the formation of those Spirits. I might here allege what Van Helmont saith in his Chapt. De Tumul● Pestis, viz. That not only the Idea and the Imagination of terror are form in the inward Archaeus of the person invaded by the Plague; but that the Toad, which hath, as he saith, a perpetual hatred against man, finding himself taken, and hanged by one of his hind-legs, and in a condition of dying, conceives an Idea and an imagination of terror by the sight of the man, that often presents himself before his eyes, and whom he looks upon as his capital enemy, and that the same Idea or the same fancy of terror, which the Toad hath conceived by this means, forms in him such impressions and qualities, as are permanent even after his death. Then this Author will, that of this body, that died in those Ideas of terror, mingled with the parts that have issued thence, and with the wax that shall have received them, you shall make Trochesque's, which being taken inwardly, and carried about you, or applied, shall have the virtue of curing as well as preserving from the Plague, by mortifying by their Specifique quality the terror which the inward Archaeus of the person may have conceived of this evil. Now since this Sentiment of Van Helmont hath found place in the minds of many men, yery capable to judge of it; who have been thence induced even to make exactly that preparation of Toads, which he hath taught in the same Chapter, and which I can assure I have myself made to satisfy the desire of very able Physicians; having also known many persons giving great credit to it, and carrying continually about them of those Trochesques whilst there was talk of the Plague; methinks, that the formation of the enraged spirits, which I ascribe to the Idea and imagination of revenge, conceived by the Viper when she is vexed, is incomparably more maintainable, and much easier to be comprehended, as well as the entry of the angered Spirits through the Openings made by the Teeth; because not only these Apertures are wont to be deep, but also because the teeth being hollow, serve for a Funnel to intromit those spirits, that accompany the biting, and that produce afterwards in the body bitten those dismal effects of vengeance, which the Viper had conceived when she felt the ill done her; And the letting in of those Spirits through the cavity of those teeth is so much the more easy, because there is also at the end of each great tooth a hole, which, though very small and almost undiscernible by the eye, may yet be discerned by a Microscope, & hath accordingly been lately seen in some public Assemblies at Paris, in the presence even of persons very affectionate to Sign. Redi.  
What shall we say of the imagination of Fright and Constraint, that a Toad also impresses in a Wecsel, which having seen and been seen by that ugly animal, at a certain season of the year, and always in summer, can not avoid to run a pretty while round about it making a continual shrill noise, as if she cried for help, whilst the Toad remains moveless with his throat open; and which after a long troublesome motion is constrained to come and render herself into that throat. The thing is too well known in divers places of France to doubt of it; and I can assure to have heretofore seen it myself; and that after I had well observed and withal wondered at the force of those Ideas, appearing in the agitation of the Weasel, and in her being constrained to fall into the mouth of the Toad, I had the satisfaction to kill the Toad in that moment, and so to save the Weasel, which quickly run away, finding herself delivered by the death of the animal, which was followed by the extinction of those Ideas, that before had had so much power over her. This effect cannot be ascribed to the foam, nor to any material part of the Toad, since the Weasel flies from him naturally, and falls not into his mouth but in spite of her teeth. Besides that the foam of the Toad, which the Weasel failed not to meet with in his throat, can work nothing, seeing the Weasel saved herself immediately after the death of the animal. We therefore must needs seek for the cause of all these effects in the Spirits.  
Moreover, what will Sign. Redi say of a mad dog, which, in the pervertion of all his senses and of all the ordinary functions of his body, breathes after nothing but mischief, and makes it his business to reduce into the same miserable condition all men he sees, and even his own master, as well as all animals he can come near and bite? If then the mad Dog hath the power to make pass the same Ideas and the same imagination, which have seized on him, into all the creatures that he can come to bite, and into man himself, though of a very different soul and nature from his, by doing no more than with the edge of his teeth to touch the superfice of the skin, and that through his coaths that may retain and wipe off all the foam adhering to the teeth, and liable to be accused of having a hand in the mischief; as is very well observed by Van Helmont in the same Chapter? If, I say, this dog hath the power of communicating his evil to all sorts of animals, from one to another, without a limit, and without excepting any kind; Why should he think it incredible, that a Viper is able by her biting to carry her enraged spirits into the bodies of such men and other animals as she can light upon; That these spirits are capable to kill the animal bitten; and that they effect this by the perturbation and corruption, they introduce into the whole mass of blood; forasmuch as they do manifestly hinder its circulation, and the communication of the natural spirits, that were wont to be conveyed into all the parts? Considering withal, that they do not extend themselves as far as those of the bite of a mad Dog; seeing none of the Animals bitten by a Viper, have any venom diffusible either by their biting, or otherwise, as long as they live, and that they may be safely handled, and even without danger eaten after their death.  
I say besides, that if it be true, that a man, who hath at all times the same spittle and the same teeth, & who hath them not pointed nor shaped like those of a Viper, is capable to introduce the Gangrene, and to cause death itself by a by't made by him in a rage; whereas another and longer bite, made by the same man not enraged, is not accompanied with any ill accident, and is healed like a simple wound; This being true, I say, we ought to think it neither strange nor impossible, that a Viper, which hath long and piercing teeth, and which shows the force of her being vexed by the nimbleness of her biting, should be able, by biting when enraged, to make animals feel the mortal effects of her vexed spirits.  
What shall we say of the pricking of a Tarantula how slight soever? shall we declare it to be exempt from the idea and imagination of this little animal, since it impresses it so strongly and differently upon persons that have been pricked therewith, insomuch that it perverts in part the senses and spirits, conforms them to his stirring and skipping nature, and constrains them at certain and set times to continual dancing for several days, and which having left a contumacious leaven of the same ideas, faileth not to produce the same effects every year, and, if you may believe Authors, as long as the Tarantula liveth, and until the same ideas be extinct by its death. And though I doubt not but that Sign. Redi hath seen very many examples of persons pricked by Tarantula's, there being store of them in Italy; yet I shall not forbear here to recite that of a Neapolitan Soldier, who hath been these four years among the French infantry. This Soldier, whom his Camarads called Tarante, because he had been pricked by a Tarantula, is still to this very day in the Royal Regiment of Roussillon. He never failed to feel every year at a determinate time (viz. about the 24 th' of July) the effects of that sting, which he had received before he came into France. He was always sure of the time about two or three days near it. And when the ideas of the sting were found exalted to a degree capable to produce their effects, he began to dance, and desired to hear without interruption the Violins, which the Officers of that Regiment caused to be played for him out of charity; to which he answered continually, keeping time very well, without being tired, for three days, eating and drinking, without interruption of his dance; and being very impatient of any discontinuance of the play of the Violins, and that the more, if the intermission was any thing long; for than he became altogether livid, and fell into grievous swoundings. He pleased himself whilst he danced, to have in his hands several naked swords, one after another; to see about him many Looking-glasses, to behold himself in them dancing; to be environed with much people, and, that he might hinder them from going away, to take from them their Gloves, Ribbons, and such other things; being very careful to keep all he had taken from them unto the fourth day, which being come, his eagerness to dance abated, and at length quite ceased; he remembering all he had done, and knowing all that were about him, to every one of whom he rendered very exactly and without any mistake all he had taken from them, though he had to do with a thousand people. After which time, he passed the remainder of that year, and the whole interval of his Paroxysines without any inclination to dance. He was naturally melancholic, in appearance of no great parts, neither had he learned to dance. He hath been seen thus dancing every year by thousands of people, and particularly in the Camp Royal Anno 1670. where the King himself and the whole Court saw him. And this hath been so beneficial to him, that the ordinary time is passed this year without any assault of this evil, which he had great apprehensions of, finding himself at that time engaged in a march, and fearing he should want Violins at the time that the sit should take him.  
Now since the pricking of this Animal, though very small, and in a manner like that of a small fly, being made even through stockings or clothes, is able to act equally upon the body and the mind of the person stung; as leaving behind such long and strong impressions, and causing such irksome returns; To what can we ascribe all those different effects, if it be not to the idea or imagination of the animal stinging, or of the person stung. 'Tis needless, to allege here the effects of the idea or imagination of Women with Child, nor of that of Jacob's Sheep. I think I have said enough to justify the possibility of the idea or imagination of a Viper's revengefulness, for the forming of angry spirits, sufficient to impute unto them all the venom, and to exclude from it the yellow liquor.  
After this, Sign. Redi must not wonder, if I, who make profession of Chemistry, (of which I have the honour to read public Lectures in the Garden Royal) who do every day exercise myself in separating the spirituous parts from the gross ones in mixed inanimat bodies; and who have not been able to find in any corporeal and sensible matter the true cause of the strange and sudden productions, observed in the biting of a live Viper; If I, after all this, I say, have thought myself obliged to seek for it in the Spirits; if having found it there, I have abandoned his party, and communicated to the public the discovery I have made.  
Yet I am not overmuch surprised, that Sign, Redi, being in this matter prepossessed by corporeal gross things, still persists in his sentiment, since in the preparations, that do altogether depend of my profession, and which I ought to know well, he rejects spirituous substances, which he relishes not, sticking only to the more material, which are the least, and in very small quantity; which doth not keep him from believing them to be the best. You may see, what he writeth of it about the end of pag. 76. and at the beginning of pag. 77, of his first Letter of Observations, in these words.  
In quest nuè naturali Osservationi ho consuinato gran quantitá, etc. That is, In these my natural Observations I have spent a great quantity of Vipers, making of them daily a very great slaughter; and, to extract the subtle from the subtle (if I may so speak) I always laid aside and kept all their flesh and bones, which being dried in a Furnace, and afterwards by a quick fire with long and great labour burnt and reduced to ashes, I thence drew the Salt with Fountain-water, and purified it, and reduced it into a kind of Crystal, etc.  
Those that know all the parts of which the body of a Viper is composed, will certainly wonder, that a person so judicious and knowing hath not found, that the chief and best part of a Viper consists in its volatile Salt, and that that Salt would not fail to avolate and to be wasted by that preparation or rather destruction, which Sign. Redi hath used to extract the Salt of Vipers. They will quickly see, that when he would draw the subtle from the subtle (as he speaks) he did quite the contrary, and expelled and dissipated the volatile and better parts, returning only the gross, the fixed and the least. They will soon judge, that he should not have given himself all that labour and pain, which he saith he hath taken, to succeed so ill in his work; and that he had done much better, with silence to pass over his process, then to publish it. The way, by him taken, will be found, I think, received from the Ancients, who knew not, that all Animals abound in Volatile, and have little of Fixed Salt: And his preparation, which is very easy, would have pleased better in those times, especially in Italy, than that great and laborious Preparation of the Salt of Vipers, which was made with so great an Apparatus, and of which I have already given my thoughts, when I discoursed of the Remedies drawn from Vipers.  
I also foresee, that Sign. Redi will not receive any greater advantage by striving to attribute to himself the first discovery of the Salival glanduls, which I found on both the Temples of both Male and Female Vipers, and which I have described and delineated in my Anatomy of Vipers: For, he will not be able to persuade it to those, who shall see pag. 44. of his first Letter of Observations the discourse following;  
Se non stimassi vergogna scriver senza altra riprova, etc. That is, If I did not think it a shame, to write, without other proof, what came into my fancy, I might say perhaps, that that yellow liquor is by no other way intromitted into the above said gums of the teeth but by those Salival Conduits, found out by the famousThomas Wharton, and shown in this Court by Lorenzo Billini, a learned young man and of great expectation, in other Animals besides Man, and particularly in Staggs, and Woodpeckers: Moreover that under those Gums there are two small Glanduls, found by me in all Vipers. Yet I would not have you rely upon this thought of mine, because it may prove a Chimaera, as I believe it to be one, etc.  
I cannot comprehend, how Sign. Redi, after he hath spoken of the Salival Conduits as of a thing that came into his fancy, and by a perhaps, that is to say, not knowing it; and who declareth, that he was ashamed to write of a thing without verifying it; who exhorts his friend to whom he writes, not to rely on his thoughts, and who adds, that it may prove a Chimaera; I know not, I say, how, after he hath written all this, he can pretend to be the inventor of the Salival Glanduls, and their Pipes: For pag. 55 and 56. of his first Letter speaking of the yellow liquor, he adds,  
E questo veleno altro non è, etc. That is, This venom is nothing else but that liquor, which humects the palate, and stagnates in those gums that invest the teeth, not transmitted thither from the Bladder of Gall, but bred in the whole head, and conveyed perhaps to the gums by some Salival conduits, which perhaps are there inserted.  
Where the word perhaps, yet twice again repeated, doth sufficiently show, that Sign. Redi did speak of the Salival conduits no otherwise than as of a thing he was not at all assured of. And though he may say, that he hath had thoughts of it sooner than I, (who have not meddled with Vipers but some years after his first Letter,) that what he had written of it gave me from that time occasion and a desire to seek for those Pipes and the Glanduls that might convey thither the yellow liquor; that the belief, he had of the Generation of this juice in the whole head, induced me to search for the Salival Glanduls higher and farther off than the place under the bottom of the vesicles; and that I doubt not, that himself might have found these true Glanduls, if he would have taken pains for it. I answer, that, since he hath not done it, he ought not to be offended at my having laboured for him, and succeeded in so doing: Neither hath he any right to deny, that I have first found, described, and to the life represented the two heaps of Salival Glanduls of a Viper with all their Vessels, as well for forming, as conveying the yellow liquor into the Vesicles that cover the great teeth.  
As to what Sign. Redi saith of me, speaking of the Authors of my Book, that I have changed the words, under the bottom, into those, at the bottom of the vesicles of the gums, and there sought in vain for the two small Glanduls, which he assures to have found there in all Vipers: I answer, that whilst he is critical as to the letter of the words, I keep to the truth of the matter of fact: And I can assure, to have searched with much care, not only in the whole bottom of the vesicles, but every where under the bottom of them, but have not found any, whether great or small Glanduls, nor any thing of the colour of a Glandul, nor that came any way near to their form.  
I put it then for a truth, that there is not to be found any Glandul neither in nor under the bottom of the vesicles, and that under the bottom there is nothing but the gristly bone that gives the shape to the nose of a Viper; the two sharp ends of the two advanced bones of the skull, to which the two great teeth are firmly annexed; the conduit of the smell, that of the hearing; some small vein, some little Artery, some little Nerve, the extremity of a Muscle, and the two ends of the Salival Channels that discharge into the vesicles; as you may see it in a manner described in the Anatomy made of it by me.  
After this, Signior Redi himself shows, that it was impossible, there should be Glanduls under the bottom of the vesicles, since he saith, pag. 38. of his last Letter.  
Ne io poteva mai scrivere, etc. that is, Nor could I at all write, that those Glanduls lay in the bottom of the vesicles, if I was of opinion, that the yellow liquor did run into them after it had passed through the Salival conduits, which yet I imagined might have their Origin from or connexion with those two Glanduls seen by me, and therefore must needs be in a situation a little distant from the vesicles, and not in the bottom of them.  
For since he saith, to have meant, that the yellow juice took its course through the Salival conduits before its coming into the vesicles; He cannot find a way long enough, nor a distance great enough, for the need of long conduits, from the place under the bottom unto that which is in the bottom of the vesicles: For, there would have needed nothing but a little opening in the same bottom, to receive the juice issuing out of the two little Glanduls he hath spoken of. And he shows sufficiently, that he cannot maintain those two small Glanduls under the bottom, where he would have them to be, since now he will needs have them a little distant from the vesicles, that he may find, in the interval, a space sufficient for the vessels that are necessary to the course of this yellow liquor. Besides, that it is altogether impossible for two small Glanduls to furnish all that yellow liquor, which presents itself in the vesicles; since the two great heaps by me found in the two Temples and behind the Orbits of the eyes of a Viper, can hardly furnish each about a drop in the space of 24 hours, after the vesicles have been well voided. Moreover, it is very easy to judge by what Sign. Redi saith in his First Letter, that he understood not, the Salival Glands were seated, as they are, on the two Temples, nor so near the skull; since he saith, that what came into his fancy, was, that the head of a Viper did not convey that yellow juice but by certain salival conduits. For if he had been of another mind, he would not have spoken but of glands; or, at least, he would have begun with them before he had spoken of the conduits, which shows also sufficiently, that by this means he hath as 'twere inverted the order of nature: For, instead of placing the Glands close to the skull, and afterwards the salival conduits; he hath begun with these, and would have them immediately to receive the juice of the Brain, and to carry them to the vesicles of the gums; and that his two pretended glanduls are seated between the extremity of these conduits, and the bottom of the vesicles; though none be there, and it would be altogether useless, they should be there, because there are none but they that can at the beginning suck & digest the humidities of the brain and the neighbouring parts, and send them into the vesicles of the gums by the conduits appointed for this office.  
But when Sign. Redi accuses me of having taken the bottom of the vesicles for that which is under the bottom of them, and of not having rightly understood, as he speaks, the Toscan tongue; I may say, that himself hath not very well apprehended, nor duly explained the French terms, used by me; since he saith at the end of pag. 35. and at the beginning of p. 36. of the same last letter.  
Soura de chi gli, Autori delle novelle experience affermano, etc. That is, Whereupon the Authors of the New Experiments do affirm, that they could never see such Glanduls as I had named; but that instead of them they had found two others, which they call Salival, thus by them described, p. 31.  
For neither in all that he hath afterwards taken the pains to transcribe out of my book on that subject, nor in all the rest of my Section upon the Salival Glanduls, he can have read; that I say to have found two Glanduls, but, Glanduls; there being a great difference in good French, between Deux Glandes', and Des Glandes', two Glands, and, Glands. And when, describing the Glanduls, I say, that they are seated on the two sides of the Craniuns, I say afterwards, that there are many small ones joined together, which may be called Conglomerate Glanduls. And yet more; I speak of an Heap of Glanduls; so far am I from speaking only of one or two Glanduls, as Sign. Redi hath represented me to have done.  
And since, in hopes of better maintaining his cause, he hath given himself the trouble of copying word for word, in his last Letter, only the most general place of my Book, and that which was the least contrary to it, in my Section of the Salival Glands. To show therefore on my part, that the Glands, found by me, are very different, and that even they are quite another thing, than the two small ones spoken of by him; I thought myself obliged to transcribe hither out of my book what he thought not necessary for him. For in the same Section, p. 30. (in the English version, p. 33) I speak thus of the salival Glands.  
These Glands are found in all the heads of Vipers, both Males and Females; they are seated on both sides, and joining to the skull, in the hind-part of each round of the eyes, and at the same height with them. There are many small ones joined together, which may be called Conglomerate Glands, that are easily distinguishable by their form and colour, which is different from the Muscles, neighbouring to them, and of which there is one, that may be called Temporal, which in part covers them by its extremity. This heap of Glands appears there of the bigness of the neighbouring eye, and extending itself in length, continues its progress in the Orbite of the eye, below and in part behind the eye. Each Gland hath its little Lymphatique vessel, which parts from it as from a little Teat, and goes disgorging itself into a greater vessel, that runs all along and under these Glands, and passeth into the Vesicle of the Gum, and terminates in the midst of the Articulation, which the root of the great teeth makes with the advancing corner of the said Orbite, and with the little Bone, which by its other end is articulated in the middle of the upper jaw. This principal vessel, which being considered alone, is very little in appearance, but is not so in effect, seeing it receives the discharge of all the small vessels that come from each Gland, empties itself into the bag of the gums, and carries thither that Salival juice, which may have qualities approaching to those of the Saliva or Spittle of man, or of the foam or drivel of divers other Animals.  
The Nerve, which serves in the Nostrils to the faculty of Hearing, runs for some space along these Glands, which are also, as I have already said, small Veins and Arteries.  
But having well considered the substance, quality & situation of these Glands, we judged their formation not to be in vain; but that their Use, in all likelihood, was, to receive the humidities both of the Brain, the Eyes, and the neighbouring parts; and that their discharge was very convenient, and even very necessary to the parts, which receive that liquor; as well for moistening the ligaments of the great teeth, and to keep them in a condition of bending at such time when the Viper will bite, as for bedewing and increasing the teeth, which Nature hath form and set in the midst of this Juice.  
For the rest, examining and tasting the Glands as well as the Juice, we found a taste altogether like that of the Gums, which Sign. Redi hath described; namely, very near the taste of the Oil of Almonds, without all bitterness, though it leave, a while after, a little acrimony in the mouth, such as may be discerned in all kind of Spittle.  
I could add here, what I said of the Salival Glands of Snakes, their difference from those of Vipers; and I could allege, that I believe myself to be likewise the first Discoverer of them. But because so prolix a Citation might prove tedious, and that those that desire to have more light therein, may easily find the rest in the abovecited Section of my Book, I shall not transcribe it hither.  
Mean time 'tis very easy to judge from my whole Discourse, and from the exact Description, made by me, of these Glands, and their neighbouring parts, that they were not known to me by Fancy. Their situation very distant from that place under, and even from the sides of, the bottom of the vesicles of the gums, shows sufficiently, that they are neither in nor under the bottom of those vesicles, as Sign. Redi hath pretended; and their great number makes it appear, that 'tis quite another thing, than the two little Glanduls he speaks of, and which are not to be found neither.  
I entreat the Reader, well to consider those I have discovered, as they are represented in my third Cut, as well in that part where the Temples are of a Head cut, marked C, (where their shape and situation is represented to the life, as they show themselves before they are severed;) as in the enclosure of a Viper's sceleton, which is there also exhibited; where he may see them in their upper and lower appearance, drawn out of the Head, and by their ligaments fastened to the hind-part of the Eyes, and to the body of the Brain. I came not to the full knowledge of them till after much pains, and a very long and particular search. I did not content myself to seek a great while in the bottom, and under the bottom of the vesicles of the gums; but, to find these Glands, I have flayed and dissected a great number of Viper's heads, as dextrously and nicely as I could; and I have used all means well to examine them; among others, I caused many heads to be gently boiled in a little water, as well to consider the divers sutures of the skull, and to separate all the parts from it; as to remark well the form and the connexion of these Glands, to draw them out whole, and joined, as they are, to the Eyes, and to divers bodies of the Brain, to which the marrow of the Spain is annexed; and to have all these parts entire, and such as I have caused them to be engraven.  
Me thinks, that all these cares, followed by so good success, may well deserve, my Discovery of this great number of Salival Glands with all their vessels, should not be envied me by Sign. Redi; considering I do sufficiently appear to him incapable of envying him any of those sine things, he hath already found, or may find hereafter in his curious researches.  
There remains no more for me to do, me thinks, than to satisfy Sign. Redi as well concerning the Uncertainty, wherein he is touching the Power of the Volatile Salt of Vipers for the curing of their bite; as about the Objections, by him made against my Experiments of the Head and Neck of a Viper, for curing Dogs bitten by it, and which I have also thought should be efficacious to cure men in the like case.  
He opposes nothing to the Virtue of this Volatile Salt, but that he remits the Reader to the time he will take, Chemically to prepare this Salt, and to make the Experiment therewith. But he saith, that he hath made many trials with the Heads and Necks of Vipers, and found first; That, having made two great Dogs aforehand to swallow, each the head and neck of a Viper, and, afterwards caused both of them to be bitten by other Vipers, those Dogs died not: And that, having caused to be bitten two other Dogs of the same bigness, that had eaten neither head nor neck of a Viper, they died neither. He saith further, that having made a Pullet to swallow one head of a Viper, and a Capon two, and caused them to be bitten, they both died soon after. He adds, that having the next day made ready some heads of Vipers, he caused them to be forced down the throat of two little Dogs, of which he caused the least to be bitten in the leg near the anus, and the other, in the tongue, and that they both died; That he made the same Experiment upon eight Pullet's, two Kitlings, two small Rabbits, and six Pigeons, even with rubbing the place bitten with the blood of the Viper; That also the six Pigeons were bitten by the heads of Vipers, dead several days before, and that all these animals died; That lastly, he had fed two Pigeons for there days with the flesh and broth of Vipers, and being bitten thereupon, they died likewise, this aid notwithstanding.  
For Answer to all these Experiments, I make use of the same Generals, that Sign. Redi hath done against mine, which are to be found pag. 16. of his last Letter; where he saith: That a Viper more easily kills lesser Animals by his biting, than great ones; that, according to the bigness of the Animal bitten, and according as the place wounded is more or less provided with veins or arteries; that, if from the wound of a Viper much blood issueth, the Animal not only dyeth not, but does not so much as feel any great inconvenience; that it also falls out sometimes, that the Animal bitten escapeth, after it hath endured many mortal symptoms; and that this may come to pass by the sole assistance of Nature.  
As to the two other Generals, which he allegeth in reference to the letting in of the yellow liquor; I did not think fit to allege them here, both because I agree not as to the possibility of the fact, and that I have elsewhere declared myself sufficiently about it; as also that they make not to this purpose. But I think it more material, to add here two other Generals to those of Sign. Redi, and to say: That the biting is more or less noxious, not only according to the place bitten, but according to the degree of the Vipers being vexed when she is to bite, and according as her teeth have more or less penetrated. And reasoning particularly upon these experiments, I say, that the dogs which I had caused to be bitten every one thrice, & were cured by making each of them swallow the head and neck of a Viper, were of a very middling size, that it is very difficult to found a certainjudgment upon the great ones, which Sign. Redi hath used, as 'tis also, to pass it upon them that had swallowed the head and neck of a Viper, and those, that had not done so, that all the other little animals, which he employed, as well the Pullet and the Capon, as the Pigeons, Catlings, Puppies, and little Rabbits, had not of themselves strength enough to resist for a time the enraged spirits, nor to find the effect of the remedy; especially that which was bitten in the tongue. For, I firmly believe, that there is no animal, great or small, which being fiercely bit in the tongue by a Viper well vexed, can avoid death, what aid soever you minister to it, because of the nerves, veins & arteries, disseminated through the tongue; and because that the angered spirits finding a free entrance, produce there all the effect they are capable of, with so much violence and nimbleness, that nothing is able to stop them. But in all curable bites I shall not easily be induced to renounce the help, which may be given by the head, neck, heart, liver, and divers other parts of a Viper (especially of her that made the bite) for the cure of the animals that have sufficient strength to resist a while, and to expect the benefit of this kind of remedy. I believe also to have great cause not to exclude from it man himself; as also to prefer the parts of the same Viper that hath bitten, to those of others; because they must needs have greater cognation and more consent with the vexed spirits, that issued from her. Concerning which I think it not amiss, to impart to the public an accident that happened in the Royal Laboratory of this City, whilst my last experiments were making.  
A young man that had made a good progress in his studies, desirous to perfect himself in both ways of Pharmacy, and chiefly addicted to my course of Chemistry, was near me, in the midst of a great Assembly, on the 2 d day of my experiments. After I had made some, whilst I was entertaining the company, the fancy took him, in imitation of me, yet without my knowledge, to take a Viper with his hand, and to seize on her head: which he did not with that caution that is necessary, as not holding her so fast but that the Viper took her opportunity, and struck one of her great teeth very deep into the middle of the upper part of his left forefinger. Having been made acquainted therewith, I removed, as much as I could, all fear from his spirit, and advised him to betake himself to the necessary remedies. The credit he gave to the truths contained in my book, often read by him, induced him to say, that if I thought well of it, he would eat the head and neck of the Viper that had bit him. Commending his courage, I seconded his good inclinations; for, I caused slightly to be broiled on coals the head and neck of the said viper, and made him eat and swallow it hot, in the midst of the company, adding to it the heart and liver broiled likewise. After which I said, I doubted not but what he had done would be sufficient to cure him; yet to be the surer, I would give him some volatile salt of vipers, especially he being a person whom I did much esteem, and for whose health I had and ever should have a great concern. I thereupon immediately gave him a dose a fifty grains of this volatile salt, dissolved in four ounces of water, and assured him there was not any danger after this. The young man remained in the midst of the company, & stirred not from the place, till the meeting ended, and then he took a little fresh air. He was afterwards a couple of hours in the Royal Garden and the Laboratory; during which time he now & then found some little sickness about his heart; but being come to his own lodging, he was ready to sup as he was used to do, and would have done it, if I had not thought it better for him to take another dose of the same volatile salt, which had so good effect, that the next day, after he had dined well, he came again to our meeting; which did much surprise all those that had been witnesses of the bite. Since that time he hath ever been very well. Now though his wound appeared much deeper than that of the Germane gentleman, that was bitten the 1st day of my former experiments; yet had he none of those grievous accidents, that befell him, & were by me described in my book: for he had no other pain but that of the hole of the bite, nor had he so much as a Fever. The wound only rendered some drops of blood, by means of the ligature, I caused to be made on the top of his wounded finger, which did never swell, and healed up as if it had been made by the prick of a pin, without any Cicatrice appearing; so far was it from a Gangrene, or Scar, as some fancied he would have.  
The thing hath been too public, not to be credited every where; and I think not, that Sign, Redi himself will doubt of it; but rather that all things have concurred together to verify all I had advanced in my book, of which he hath contested some particulars, and could not resolve himself about others. However, if he have by him any remedies, more quick and more sure for the cure of the bites of Vipers, the public will be much obliged to him when he shall please to impart them, as I very willingly communicate these I have experimented. I shall not speak here of divers Experiments lately made upon Vipers by very able persons at Paris, which confirm not only the perfect innocence of the jellow liquor that is in the vesicles of the Gums, but which warrant at the same time my adscribing the venom to the enraged spirits. These truths will be better received from their hands, and they will be much more advantageous to me, than if I did attempt to publish them now. For doubtless there will be found in them very curious things, and they are like to be of more importance than what I might be able to say of them. Besides that I am far from usurping the honour due to others, and from attributing to me the obligation, which the public will owe them for it.  
For a conclusion of this discourse; since Sign. Redi hath not found in the whole body of a Viper any other part but the jellow juice to which he can assign its venom; since on my part by the new experiments, he hath desired of me, I have sufficiently justified the innocence of the jellow liquor in the Vipers of France, and the great conformities, there must needs be in the same with that of the Vipers of Italy, asserting withal the venomonsness of the angered spirits causing the death that ensueth the bite; and since lastly the Vipers of France do kill as soon and in the same manner as those of Italy do, and even without any intervention of the jellow liquor: These things being so, I esteem, that Sign. Redi would do very well, if, to satisfy on his part the expectation of the public, and without adhering any longer to the jellow liquor, which is so reasonably contested, he would take the pains to labour to find out some new subject, that might be common to the Vipers of France and those of Italy; that might have the same disposition of matter, and the same power of acting nimbly; and that might with reason be equally declared the true seat of their venom; to the end that afterwards he might as justly exclude from it the enraged spirits, as I now exclude from it the jellow liquor. But if on the contrary it comes to pass, that he can find none other, I believe not, that for the future he hath any ground to maintain his opinion, no more than to contest mine.  
Concluding this dissertation I shall say, that the contrariety of opinions, which is between Sign. Redi and me, in the most essential things of the Viper's poison, may also be observed upon another account about the same animal: For, the more he expresseth p. 39 of his last letter, the aversion and hatred he hath against it, the more I esteem it, and the greater pleasure I take to handle, to examine, and to prepare it. Nor can I sufficiently praise the excellent qualities, which so rare a subject possesseth, nor the admirable remedies which it furnisheth: Which are the considerations, that have heretofore induced me, and oblige me still to call the Viper one of the chief Pillars of Physic.  
It may be, that for this once Sign. Redi will not doubt but that a discourse as rude as this, composed among coals and furnaces, which I have seldom quitted of late, is mine. He will doubtless judge, that, if more understanding men had put their hands to it, the reasonings thereof would be more subtle, the style more polite, and the expressions more elegant; and the Greek and Latin quotations would not have been spared therein, both to strengthen the arguments thereof, and to adorn & enlarge the volume. But for all the contrarieties, which the different conceptions have bred between Sign. Redi and me, I shall always have a very great and a very disinterressed esteem for him; and so much the more, because I have great reason to conceive some good opinion of my book, since it could deserve that so intelligent & famous a person hath vouchsafed to read it again and again with pleasure, as he saith himself, that he hath taken the pains of transcribing many pages out of it word for word, and hath made it famous by his answer, and by that also which a person of great parts, and a high reputation hath made to it, addressed to himself on this subject. I cannot but much glory in it, and highly declare myself his obliged. And if it should come to pass, that the diversity of his experiments, the force of his arguments, or the esteem he hath acquired among the Learned, should carry the bell from me in the spirits of all the world; the victory, which he should thence obtain, would not be much less advantageous for me, then if the truth of my experiments, accompanied by my reasonings, had been able to balance or even to prevail over his Sentiments and the writings of so Illustrious a Person.  
FINIS.