while in the womb is most probable that all viperous creatures after the birth cannot live long without breath is most certain yet I do not find the uses of Respiration so clearly determined but that it may afford us matter for farther enquiry The common received Opinion is that Respiration serves chiefly for cooling the heart next that it yields matter for production of new vital spirits and lastly that it discharges the lungs of a fuliginous excrement which seems to transsude from the Mass of blood into the branches of the rough Artery that the heart is cooled by breathing is very probable but not immediately for the air going no farther than the lungs first cools them next the blood in them and consequently the heart becomes less hot than otherwise it would be but this is in effect no more than is obtained by bathing the limbs in cold water which does a together if nâ—t more effectually cool the Mass of blood as much as the air in breathing can be conceived to do it and yet bathing will in no wise become a Substitute to breathing Nor does the generation of vital spirits seem to be the chief use of the air in breathing in regard it is not easie to conceive any such contrivance in the lungs that may serve for the letting in of air into the veins and arteries which contain the blood without endangering contrariwise the effusion of that precious juice much less has Anatomy as yet discovered any such passages unto us Lastly as I shall not deny but that the lungs do discharge themselves of a fuliginous excrement by breathing so I think it as true that this is none of the principal uses of Respiration Nor is it at all likely that either the heart should grow so hot or that the vital spirits should vanish so fast or the fuliginous excrement be accumulated in that quantity upon the intermission of breathing for a short time only as to indanger our lives beyond recovery as the absolute necessity of Respiration would seem to inforce Before I come to deliver my own Opinion I shall make a slight digression concerning the circulation of the blood which will not a little illustrate what we are about to say concerning this Subject 2. 'T is manifest in the circulation of the blood in Animals that the blood is moved from the left Ventricle of the heart through the great Artery into all its branches from whence it is brought back by the smaller veins which discharge themselves into the Vena Cava from whence it is returned into the right Ventricle of the heart from whence it is sent by the Vena Arteriosa into the lungs and so brought back again into the left Ventricle of the heart by the Arteria Venosa And in this circular motion of the blood life chiefly consisteth and if the same by any chance should cease or intermit though but for a very small time less than a minute death would unavoidably follow In this motion of the blood it is observable first that as the pulsation of the heart sendeth it through the Arteries into the whole habit of the body so the return of it by the veins seems to depend chiefly upon the tonical motion of the body for the parts being extended by the flowing in of the blood somewhat beyond their tone do again gently subside and thereby continue the intended course of the blood toward the heart again An argument hereof is that all Paralytick parts grow immediately cold and that for no other reason than that the tonical motion together with the power Locomotive ceasing the circulation is either very weakly or not at all performed through that part which then grows cold for want of that constant fresh supply of blood which formerly kept it warm But herein the tonical motion is not a little helped by exercise and labour which we find by experience to cause the heart to beat quicker and oftner as also to induce a necessity of breathing more frequently and this it doth no otherwise than by accelerating this circular motion of the blood which then enforceth the heart and lungs to double duty Our second observable in this circular motion of the blood is that there passes as much blood from the right Ventricle of the heart into the â—uâ—gs at every pulse taking one time with another as is sent from the left Ventricle into all the parts of the body beside Nor can it be otherwise the left Ventricle being supplied from the lungs only and the lungs receiving it not elsewhere than from the right Ventricle of the heart So that to continue this circular motion of the blood 't is necessary the supply neither exceed nor come short of that quantity dispensed from the left Ventricle of the heart into the whole body the Lungs excepted From hence it follows that there flows a greater quantity of blood by many degrees into the lungs than what is sufficient for its own private use As also that the blood in the lungs must of necessity move very much faster than it does in any part of the body though we take for example the great vein or artery themselves and that in the same proportion as the Vena Arteriosa and Arteria Venosa are smaller than the trunks of the foresaid great vessels For let the same quantity of liquor be conveyed through a pipe whose capacity is but one fourth or one tenth so big as another pipe through which the like quantity must pass in the same time and it is evident the liquor must run four times or ten times as fast through the smaller pipe as it does through the greater And thus it appears that a very considerable part of the Mass of blood is continually running through the Parenchyma of the lungs and that at a much swifter rate than it doth through any part of the whole body beside 3. Farther before we proceed to treat of the use of Respiration it will not be amiss to consider what kind of motion that is which the lungs are exercised with in breathing Nor is it any other than a motion of dilatation and constriction whereby the lungs are reciprocally opened and shut somewhat after the manner of a pair of Organ-Bellows the air entring into them when dilated or opened and receding again upon their subsiding And this is what we call Respiration Nor yet does this reciprocation of the lungs proceed from any power to move they are endowed with of themselves For if we consider the frame and structure of them they will appear of a Parenchymous kind of substance not much unlike the liver and altogether void of Muscles without which no local motion can be performed We may conclude therefore that the lungs are moved by consent and that chiefly of the Diaphragme or Midriff in a free and ordinary breathing But in any difficulty of breathing as in the Asthma Tabes violent exercise c. not only the Midriff but almost all the Muscles of the
trunk of the body namely those of the Belly Chest and Shoulders seem to afford their assistance in this great work of Respiration The motion of the Midriff is first downwards whereupon the lungs follow and the air is admitted and again upwards whereby the lungs are compressed and the air excluded Thus you see that as the construction of the Midriff so is its motion somewhat different from that of other Muscles which as being well known we shall not need to spend longer time about but come to the publick use of the lungs in the Oeconomy of our bodies 4. In the circulation of the blood we ascribed the reduction of it again into the right ventricle of the heart to the Tonical motion of the body where yet as we have said the blood moves but very slowly if compared with that swift and rapid motion it is carried on with through the lungs where it moves perhaps ten times as fast as in any other part of the body as has been already proved Which notwithstanding we shall not be able upon perusal of the structure of the lungs to conclude that they are endowed with any considerable tonical motion as may be gathered as well from their want of Muscles as for that their substance is very spongey and flaccid and their common integument is but one thin membrane Nor was it without a particular and that a most excellent design that Nature thus contrived the lungs with little or no tonical motion in them For first had this Tone been equivalent to the Mass of blood to be returned by it it would much have retarded the influx of the blood into the lungs and consequently have hindered a great work of Nature upon it there as shall be shewed hereafter But chiefly for that it has largely supplied such defect by the assistance of the Diaphragme which becomes the cause both of dilating and contracting the lungs according to the occasion and at the will and pleasure of the Animal And this is indeed the first and principal Office of the lungs as to what concerns their reciprocal motion Namely that upon the subsiding of them in Respiration the blood may be vigorously squeezed out of them through the Arteria Venosa into the hearts left Ventricle And because the substance of the lungs is very tender Nature contrives that not the Diaphragme immediately but the air inclosed in the cavity of the brest for this very purpose only being first streightened and crowded as it were together by the motion of the Diaphragm upward should cause this compression upon the lungs while by its Elastic power it endeavours to dilate it self again to its usual dimensions Nor could any way of compressing the lungs thereby to discharge them of the superfluous blood have been contrived more equal for this pent air is as apt to press upon one part as on another Nor yet more gentle and secure for what contact could have been more delicate or less apt to wound the tender membrane of the lungs than the air inclosed in the brest about them Nor need any doubt but that the air thus comprest and streightned is of strength sufficient for this service and that there is such a Spring in the air who shall but consider with what force the air breaks forth of the Wind-gun and other Pneumatic Engines A farther confirmation hereof may be had from hence that such wounds as perforate the brest if left open but for a little time do quickly cause a difficulty of breathing and I do not much question but if both sides of the brest were perforated it would as certainly dispatch a man as hanging and that almost in as short a time Farther in the dissection of live Animals Respiration continues long after the Abdomen or belly is laid open but immediately ceases upon dividing the Diaphragme or Midriff 5. Whether the air that enters into the lungs by the Wind-pipe have a share in this compression of them for the discharging of the blood or not I am as yet not well satisfied At first view this compression should seem to be best made upon drawing in our breath between the air implanted in the cavity of the brest and the air in the rough Arteries or branches of the Wind-pipe but at such time the implanted air is but little or not at all contracted and therefore we must conclude that either the air taken in bears no part in this compression or which is most probable that the sanguine Vessels of the lungs are not only strongly compressed upon expirations but also upon inspiration that is so often as the lungs are removed from their natural middle or indifferent scituation whether expanded or contracted Viz. Tà m in quiete externâ quà m internâ We must likewise allow the air to cool the lungs very considerably and that it discharges them of a fuliginous or rather vaporous excrement But these are â—s we have said the less principal uses of Respiration As for the airs becoming the matter of Vital Spirits in Respiration I shall say no more than that I neither find any need of it nor any may for the mingling of it with the Mass of blood 6. Allowing what has been said concernâ—ng â—he use of respiration we may perhaps â—â—nd out a more commodious reason of sighing than has been yet assigned For if a man shall for a while either wholly forbear breathing or at least breath seldomer â—nd lower than is his usual custom the â—unges in the mean time swell and fill â—hemselves with blood for want of that â—requent and strenuous compression formerly equal to the influx of the blood while the pulse is not so full as ordinarily â—he hearts left Ventricle not receiving its â—ue supply from the lungs which in this â—ase receive more than they deliver Hereâ—pon a man is necessitated for avoiding â—uffocation to fetch a great breath or â—â—gh which may more strongly than usuâ—lly compress the substance of the lungs â—nd reduce them to their former estate And thus great attention any deep contemplation sad thoughts and a melancholick constitution do often become the cause of frequent sighing As also a natural sloth or less aptness in the lungs themselves or Diaphragme to motion will sometimes make this passion customary and habitual And it is observable that the pulse rises very much upon sighing for the first stroak or two at least the blood coming to the Artery again in that abundance that a man may feel the tingling of it at his very fingers ends 7. Furthermore it may not a little strengthen our Assertion that in all great difficulties of breathing and where there is most imminent danger of suffocation to let blood in good quantity is commonly prescribed as the last remedy and which seldome fails of giving at least a present relief let the cause be what it may be And this it seems to do by diverting the course of blood from the lungs while they gently again discharge themselves of
their burden And in case of hanging or strangling letting of blood in great quantity has sometimes saved mens lives that have been executed and this by no other ways that I can think of than by helping to discharge the lungs of their oppression as has been already said 8. And thus we have if our Opinion fail us not discovered the true use of Respiration We have also of consequence freed the heart of almost one half of the task imposed on it by the modern Physitians For since the circulation of the blood consists of two parts viz. First the conveying it from the heart or center to the rest of the body as to a kind of natural circumference And secondly the returning or bringing back of the blood again to the heart The first part we conceive to be the Office of the heart The second part seems to be the work of every particular member to discharge it self of its own superfluities For which purpose nature hath endued them with a tone or tonical motion sufficient for that service the lungs only excepted wherein Nature hath worthily imployed her industry by the additional contrivance of Respiration through the assistance of the Diaphragme which labour of the lungs in Respiration for the returning of the blood to the left Ventricle of the heart seems to equal that of the tone or tonical motion of all the other parts of the body for the lungs convey the same quantity with all the rest that is to say the whole Mass of blood through them and that in as little time as the same passes through the rest of the body And if it carries it not so far it moves â—t so much the faster And so we shall have entitled the lungs to one full quarter part of this work of the circulation of the blood leaving an other quarter to the tonical motion of the body And the first and worthier half of dispensing blood and life through the whole body to the heart as its proper office and duty What part the lungs may justly claim to themselves in the business of Sanguification we shall more conveniently find place to consider of in the following Chapter CHAP. IV. Of Sanguification THe Chyle when separated from the remaining unprofitable parts of our Aliment is by proper vessels of its own the discovery of modern Anatomists conveyed directly into the Subclavial veins and from thence into the right Ventricle of the heart where it is mingled with a larger quantity of blood returning home by the great vein together with which it is immediately transmitted to the lungs where though it make great hast through and moves very impetuously as has been said yet by reason of the length of the way it continues a considerable time and is more perfectly mingled with the blood and wrought up together with it into one Mass and at the same time acquires both the name and form of blood as Physitians term it and so is fitted for the heart from thence to be distributed to the rest of the body where after what manner it is circulated we say not as a thing already sufficiently known and whereof we have delivered our sense already 2. That Chyle is very easily mixt with blood is evident for that it is the matter whereof all blood is made by a farther continuation of that fermentation or concoction begun on it in the stomack Nor yet is the proportion so great between them but that upon mingling the dissimilitude of parts becomes immediately the cause of an extraordinary ebullition which is very much encreased by the reciprocal motion of the lungs whereby the blood is wrought almost all into a froth or foam by that time it gets into the left Ventricle of the heart Which sudden excess of heat is not unlike what happens upon the mingling several Chymical liquors together as Spirit of Wine and Spirit of Turpentine and other such like where the heat becomes so great that it often endangers the vessel they are contained in And this is the cause of that heat a while after meals discernable in Hectical persons and others otherwise affected and which in many appears by flushings in the face Now that the blood is wrought up to that froth we speak of during its passage through the lungs is not only suitable to reason but appears most evidently in those sanguine excretions from the lungs which happen in consumptive persons nor does that frothiness then observable proceed from the mingling with it the air we breath for that at one breathing out or expiration could not be sufficiently performed 3. The blood by several very learned men has not unaptly been compared to wine and in my Opinion the Chyle may as properly be likened to the juice newly pressed out of the Grapes which if it were by certain intervals in a due proportion poured gently into new wine or must as it begins to cool would again renew its ebullition and continue the warmth of it to what degree is requisite and that so long as this practise shall be continued And from this Illustration may be clearly gather'd the necessity and use of eating at least within certain periods or intervals to wit that by the frequent affusion of Chyle the blood may again recover its motion warmth and vigour without which supply it would soon languish cool and congeal and consequently death ensue Now that the lungs are indeed the principal Officina Sanguinis may be farther collected from Consumptions of the lungs wherein all parts of the body are so suddenly extenuated by the affection of the part 4. 'T is probable that the blood during its stay in the lungs does not actually dilate it self and rise into froth but only acquires an aptness so to do as soon as it is at a little more liberty as appears in blood spit out of them and consequently when it falls into the left Ventricle of the heart it immediately dilates it self with great force in the manner of botled Beer and in this manner does for ought I know in great part become the cause of the Diastole or expansion of the heart which being extended beyond its due and natural scituation does again violently contract it self by a power almost all bodies have of restoring themselves and which we call the tone or tonical motion And as we observe in a Switch bowed down or in a Pendulum removed out of its place that they return beyond the perpendicular so it fares in this motion of the heart whereby it is again more contracted than is natural to it and so of it self returns again to expand it self and is again violently distended as before by the influx of more spumy blood from the lungs Now though it may be objected that the pulse in the heart continues many times a long while after it is taken out of the body and when there is no longer any such influx to be pretended as the cause of it To this I answer that such pulse
of the whole body are much more compressed than in their natural state of rest and consequently do not only not admit of the usual quantity of blood and humours due to them by circulation but by their violent and frequent contraction do return them back in much a larger proportion than they now receive them whereupon the lungs become over-charged which causes frequent breathing and makes the pulse quicker and stronger than formerly distends the great vein and artery with a greater quantity of blood than is usuall Whereupon the Artery by its pulse and tone endeavours to discharge it self upon the habit of the body which not receiving it in its due and accustomed proportion the blood does in a more than a usual manner fill the vessels of the eyes and other weak parts and either by dissention compression or extravasation of blood or other humor the order and disposition of the parts of the eyes becomes so confused and disturbed that no wonder if blindness immediately or soon after do ensue Now 't is manifest from hence that where the body of an horse is clean that is to say not so full of humors and where blood abounds not over-much this accident shall not easily happen And here we are to observe that though the native tone of the eye do rather exceed that of the other parts than come short of it yet it is not sufficient to resist this influx when the tone of the other parts is so much strengthened by the violent local motions of the body 11. If we a little reflect upon the manner of the Circulation of the Blood and how by very modern discovery the Chyle is first mingled with the blood in the axillary or subclavial veins from whence it passes by the right Ventricle of the heart through the lungs into the left Ventricle from thence to be distributed into the whole body One thing very remarkable will arise to our observation namely that what part of the blood is sent toward the head by the carotides or arteries of the neck flows thither very crude and accompanied with all its excrements it having not yet received or suffered any depuration or alteration from the Reins or Spleen like that which passes into almost all other especially the lower parts of the body though indeed it seems not to be cleansed of the gall till it returns home again through the liver Now though Natures purpose herein be very obscure that the blood thus impure should be designed for the service of the most Noble part yet that so it is will farther appear by the several Emunctories or sinks wherewith the head is in a particular manner provided as the ears eyes nose palat every of which discharge the brain of a several excrement and that no longer useful to the body except what is secerned by the palat which is for the most part again returned to the stomack for the better separating of which Nature has industriously placed about the head so many of those serous vessels called the Ductus Salivares which seem here to perform the same Office to that part of the blood sent to the head which the Reins do execute to the remaining Mass Hence no wonder it is if excessive drinking do so much weaken the brain cause Catarrhs which is nothing but an over-flowing of the Ductus Salivares weaken all the faculties of the Soul and senses and at length enervate the whole body although at the same time the Reins do their duty indifferently well and this especially if the native tone of the brain be weak it being then so much the less able to discharge it self of such superfluous excrements This may be said in general that the blood is thus sent to the brain before depuration in regard of its publick Office that the same may there be farther elaborated as shall best suit with its service in that Noble part Thus much by way of an useful digression may suffice concerning tonical motion and some considerable circumstances of it which as well for the assistance it gives the heart in the circulation of the blood as for the many useful indications from thence arising in the Doctrine of Phlebotomy was most properly to be handled in this Chapter of Sanguification 12. And now I do not much doubt but whoever shall have carefully perused what has been lately said concerning Sanguification and the use of the lungs will as readily conclude with me that the lungs do bear a very principal part in the work of Sanguification for in them the Chyle is perfectly mingled with the blood in them one half part of the circulation is performed and in them the blood seems to free it self first of all from any excrement to wit a fuliginous or rather a vaporous watry superfluity which passeth out together with our breath And this seems the first and chiefest part of Sanguification The second is a farther elaborating the Mass of blood in the arteries which is performed by the pulsive motion of the heart The third and last part is the depuration of the blood whereby its superfluous excrements are separated from it and this is performed by the rest of the bowels thus by passing through the Reins it is dreined of its serous parts Another excrement it seems to leave behind it in the Spleen though of what kind is not yet well determined among the modern Physitians But on all sides it is concluded that while it passeâ— through the liver as through a Streiner iâ— is there purged of choler which in mosâ— Animals is collected in a little bladder oâ— Cistis from whence it is transmitted to thâ— Intestines where it becomes a kind of natural Clyster and provokes to the excerning the excrements of the first ways as they use to term them And this is what lay in our way to say at present concerning Sanguification CHAP. V. That often changing the Air is a friend to health Also a discovery of a new method of doing it without removing from one place to another by means of a Domicil or Air-Chamber fitted to that purpose HAving hitherto shewed what part the air acts in all fermentations and that in respect of its tone and temper Viz. its difference of rarity and density and of heat and cold and that in general only not considering what other dispositions of the Air may make it apt to promote or retard the motion of fermentation whereby it may also powerfully operate to the continuation or destruction of mixt bodies as not so directly serving for the illustration of the Subject we principally intend in this discourse Having farther made it probable that the work of our stomacks upon our Aliments as also that Sanguification it self is a kind of fermentation And lastly having asserted the publick Office of the lungs together with the use of breathing as well in promoting the circulation as elaborating of the blood And having likewise said something of the tonical motion of the body and all this
c. have been approved of in divers diseases or distempers of the stomack and guts for the same cause Nay I have heard that Paracelsus his Occidental Civet prepared will make an excellent Peptick for them that can dispense with such homely remedies 8. It is a famous Question among Physitians Whether it be better to make a meal of one only dish of meat or to eat of several meats at the same setting and it is commonly determined in favour of the simpler diet But it seems more consonant to our Opinion to allow rather of several dishes for that which is easie of concoction will help to concoct that which is harder Thus good Sauces to meats make them set easie and light upon the stomack the Sauces being easie of concoction helping the dissolution of the meats And we may surely expect a heartier nourishment from them than single dishes as we find by experience better broth to be made of several sorts of flesh than of any one and commonly the more variety the more perfect is the pottage And it s well known we are nourished by juices only and not by the solid part of our food 9. Where this ferment of the stomack is more acid than is requisite as it is in Hypochondriacal persons and such as are troubled with sowre belches 't is found by experience that to make two three or four meals in a day is better than one and that fasting encreases much the acidity Thaâ— hard meats as dry bread Biscuits and those that are less easie concoction are more useful than Broths and other light meats which will sometimes especially taken in a morning the ferment after long emptiness becoming extraordinary sowre work so violently that they will flow up into the mouth and with their eagerness set the teeth an edge and ferment the very ground But both in this and the former rule 't will be necessary to take some care that we do not eat much more of our Many dishes than we should have eat of one and that the quantity of our meat at many meals but equals or not much exceeds what we should have eaten at once or twice 10. 'T is observed that sudden change of diet has sometimes proved very fatal and been often the occasion of dangerous diseases The reason may well be that the stomack having received its tincture or ferment from food of another nature is but ill prepared for the concoction of those meats to which it hath not been accustomed and from which it has as yet received no stain or impression Such changes therefore must be made by degrees and thus I have heard that horses have been brought to live upon flesh and some men have indifferently well supported life with bread and herbs only 11. Wolves are said when pressed with extremity of hunger sometimes to tear the ground and fill their panches with meer earth which surely affords them little or no nourishment But it serves for the present to abate the edge of their appetites till they meet with some prey at which time they easily discharge their stomacks of the earth and fall to better meat This instance may indifferently well support our Assertion that hunger is rather a sense of pain from the acid ferment of the stomack than of emptiness from the Suction of the veins 12. As concoction succeeds best with rest so motion is said to help distribution Now by distribution we are to understand the dispersing of the thinner parts of the Chyle into the milky veins from thence into the Subclavials thence into the right Ventricle of the heart where the Chyle already is pretty well stained or imperfectly mingled with blood from whence it takes its course to the lungs where by the reciprocations of that part it is yet more perfectly mixed with the blood From the lungs it descends into the hearts left Ventricle from whence it is thrown into the Arteries where by degrees it receives the form and name of blood and by them is conveyed into all parts of the body In regard the milky veins have no attractive power whereby the Chyle might be suckt into them as far as could yet be fairly made appear nor has the Chyle much less any such inclination or power of moving it self that way it remains that this distribution of the Chyle is performed by the motion of the body And thus we find moderate exercise soon causes an emptiness in the â—…irst ways and begets an appetite And yet we may likewise observe that while we sit still or sleep this distribution is performed though not so speedily Now while we rest there is no other motion observeable beside that of breathing which seems to be the true cause of this distribution of the Chyle till it comes into the Subclavials for when we draw in our breaths the Diaphragme or Midriff compresseth the stomack and gently forceth the Chyle thence into the guts And again when we breath out the Muscles of the belly straight subside and strongly compress the guts whereupon the thinner part of the Chyle insinuates it self into the mouths of the milky veins and by the succeeding parts of the Chyle is protruded into the Subclavials where afterward it is moved with the motion of the blood I do not deny the Peristaltick motion of the Intestines whereby the guts distended with Chyle beyond their due tone do again by their transverse fibres contract themselves for this is also a partial cause of distribution as appears in the dissection of live Animals where this motion of the Chyle continues after the Abdomen or belly is laid open from one end to the other but is much strengthened no doubt by the Muscles of the belly besides this Peristaltick motion of the guts shews indeed in part how they are emptied but not how they are fitted with Chyle which is the first part of distribution 13. 'T is worthy observation that Butter melted and very well beaten or drawn the while becomes a much pleasanter cause and easier of digestion than if it be not beaten and yet all the difference is that by beating a great quantity of Air is every where mingled with it whereby it very much helps the fermentation or concoction of our meat in our stomacks after the same manner as is already said of whites of Eggs in the former Chapter and indeed all sauses are a kind of additional ferments That there is great quantity of air in Butter thus beaten may not only be gathered from hence that after beating it takes up more room than it did before or otherwise would do if not beaten but the same particles of air are even manifest to sense it self and the whole Mass of Butter appears beaten up into a froth so far is â—t from being made thicker thereby as we commonly express our Opinions of it â—hat indeed it becomes much thinner and lighter if compared quantity with quantity as is manifest CHAP. III. Of Respiration THat Animals breath not at all
is what the Physitians call the Myurus or Mouse-tail for that its Diadromes or differences between greatest and least expansion do continually become less and less even as it happens in Pendulums once removed from the perpendicular which continue their motion for a long time after the hand is from them that first set them awork At least this ebullition of the blood in the heart seems not a little to contribute to the continuation and strengthening of this pulsive motion In contemplation of this Orgasmus or fury as I may call it in the blood issuing out of the lungs and now to be distributed into all parts of the body Nature contrived the Arteries with thick and double coats the better to contain it whereas the veins designed for the carrying it back again to the heart at what time the blood is very much cooled and tamed are only made of single membranes as being sufficient now to hold it And this is all the difference between Arterial and Venal blood 5. It seems of all other Opinions the most probable that the blood when arrived at the extremities of the smallest Arteries is there shed upon the habit of the body in the belly or fleshy part of every Muscle each Muscle having the proportion or likeness of one of the quarters or Acetabula in an Orange or a Lemon upon the compression of which either by local or tonical motion it is not hard to conceive how the blood is again forced into the mouths of the veins and after the same manner has every Muscle its particular membrane And thus we find that blood issues forth upon pricking the flesh in any place although it cannot be imagined we should always prick a vein or Artery or we must conclude there is nothing else in flesh but a multitude of capillar veins and arteries which were absurd to be asserted 6. To make short Life it self is but a continuation of this vigorous fermentation of the blood which is so long maintained as the Mass of blood is kept hot and circulating through the veins and arteries and if done by those means and in that manner which is suitable to Nature so long the body is in perfect health If it be too violently fermented or moved it does in general become the cause of Fevers and other acute diseases as contrariwise if the fermentation be too weak from thence all chronical diseases take their original and that particularly according to the several irregularities that may happen either in excess or defect in this fermentation and circular motion of the blood We descend not now to particulars the most we aim at in this Treatise being but a general method either of preventing or curing diseases after a way not yet treated of 7. Since the discovery of the circulation of the blood it has been the Opinion of many great Assertous of it that where the indication is of letting blood it matters not out of what vein it be taken provided so many ounces be let out as the disease requires And this their Assertion is made probable by many arguments alledged by them for that purpose and but for the tonical motion of the habit of our bodies would be as great a truth as any is in Physick But the tonical motion of the parts once admitted We must likewise grant that those parts will empty themselves first that lie nearest to the incision as well for that there is less strength required to force any liquor to a shorter than a longer distance as also because the more remote parts or Muscles do exercise a kind of Antipraxia or Contranitency and so become of mutual impediment one to the other whereas the nearer parts do almost immediately discharge themselves upon the Orifice or incision 8. From this tonical motion of the whole body it happens that any particular part is sometimes preternaturally swelled either from a stroak the application of cupping-glasses or generally any other cause which may weaken the tone of the part for in such case the heart continuing its motion for the distribution of the Mass of humors it is very easie to conceive that more of them will pass into that part where least resistance is made than otherwise would have happened had the part continued in its natural tone and vigour 9. From hence likewise the reason is to be sought how it happens in letting blood that so large a quantity should in so small a time issue out at the incision made in one vein and that perhaps none of the largest For if we duly consider how quickly a man may bleed to death by the opening for instance of a vein in his arm we must conclude that the blood passes not much faster through the heart than it does at the same time out at the Orifice in his arm and that consequently there is but little blood received during this evacuation into the rest of the body which doth then by its tone discharge it self into the great vein of its Plethora or superfluous blood which returning again from the heart toward the habit the greatest part takes its way to the part where the incision was made it finding there no other opposition than what it has while it is travasated from the arteries into the veins through the smallness of their mouths which yet is in part recompenced by the multitude of them Now if it be agreed on that in half an hour a man may bleed to death or thereabout if a vein in the arm be kept open and that there will in such case be about one half of his blood let out computing what is likewise contained in the capillar vessels and what remains in the habit of the body it will follow either that the whole Mass is compleatly circulated twenty four times in twenty four hours or a natural day Which seems a little too often or that the blood circulates much faster while a vein is breathing than at other times which is not improbable or that a man may continue bleeding longer than half an hour which is not so likely or that there is not in such case of bleeding to death one full half of the Mass let out All which may deserve a more exact scrutiny but must now be left to be decided by the experiments of such as are conversant in the dissection of live Animals 10. It is frequently seen in horses that upon long and much labour they lose the sight of their eyes nay I have known some horses that have lost one or both eyes with one days over-straining either by draught or course and so became blinde of a sudden And then we commonly say they have drawn their eyes out But how the eyes should suffer or what part they take in the labour or violent exercise of the body is not so easily made out unless by this tonical motion of the body which now becomes much strengthened by the violent local motion either in drawing or running whereby the Muscles