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
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
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