Aero-chalinos, or, A register for the air for the better preservation of health and cure of diseases, after a new method / by Nathaniel Henshaw.

CHAP. III. Of Respiration. (Book 3)

inter 1.1THat Animals breath not at all, while in the womb, is most pro∣bable, 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 en∣quiry. 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 imme∣diately; for the air going no farther than the lungs, first cools them, next the blood in them, and consequently the heart be∣comes less hot, than otherwise it would be; but this is, in effect, no more than is obtained by bathing the limbs in cold wa∣ter, which does a together (if n••t more effectually) cool the Mass of blood, as much as the air in breathing can be concei∣ved 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 ar∣teries, which contain the blood, without endangering, contrariwise, the effusion of that precious juice, much less has Anato∣my, 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 ac∣cumulated in that quantity, upon the inter∣mission 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 illu∣strate what we are about to say concerning this Subject.

2. 'Tis 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 bran∣ches, from whence it is brought back by the smaller veins, which discharge them∣selves 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 a∣gain 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 perform∣ed 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 ac∣celerating 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 ••u••gs, at e∣very 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 recei∣ving it, not elsewhere than from the right Ventricle of the heart. So, that to continue this circular motion of the blood, 'tis ne∣cessary, 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 Arterio∣sa, 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 evi∣dent, 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 be∣side.

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 mo∣tion of dilatation and constriction; where∣by 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 rece∣ding 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 endow∣ed with of themselves. For, if we consi∣der, the frame and structure of them, they will appear of a Parenchymous kind of sub∣stance, not much unlike the liver, and al∣together void of Muscles; without which, no local motion can be performed. We may conclude therefore, that the lungs are mo∣ved by consent, and that chiefly of the Diaphragme or Midriff, in a free and ordi∣nary breathing. But, in any difficulty of breathing, as in the Asthma, Tabes, violent exercise, &c. not only the Midriff, but al∣most all the Muscles of the trunk of the body, namely, those of the Belly, Chest and Shoulders, seem to afford their assi∣stance, in this great work of Respiration. The motion of the Midriff is first down∣wards; 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 con∣struction

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 moti∣on, 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 notwithstand∣ing, 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 par∣ticular, 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 up∣on it there, as shall be shewed hereafter. But chiefly, for that it has largely supplied such defect, by the assistance of the Dia∣phragme▪ which becomes the cause, both of dilating, and contracting the lungs; ac∣cording 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 moti∣on: Namely, that upon the subsiding of them, in Respiration, the blood may be vi∣gorously squeezed out of them, through the Arteria Venosa, into the hearts left Ventricle. And because, the substance of the lungs is very tender; Nature con∣trives, that not the Diaphragme immediate∣ly, 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 pow∣er, it endeavours to dilate it self again, to

its usual dimensions. Nor could any way of compressing the lungs, (thereby to dis∣charge 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 de∣licate, or less apt, to wound the tender membrane of the lungs, than the air in∣closed 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 perfo∣rate 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 Dia∣phragme 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 dischar∣ging of the blood, or not, I am as yet not well satisfied. At first view, this compres∣sion 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 bran∣ches of the Wind-pipe) but at such time, the implanted air, is but little or not at all contracted: and therefore we must con∣clude, 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 com∣pressed, 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. Tàm in quiete externâ, quàm 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,

••s we have said, the less principal uses of Re∣spiration. As for the airs becoming the mat∣ter 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, concern∣••ng ••he use of respiration: we may, perhaps, ••••nd out a more commodious reason of sigh∣ing, than has been yet assigned. For, if a man shall for a while, either wholly forbear breathing: or, at least, breath seldomer, ••nd lower, than is his usual custom: the ••unges, in the mean time, swell and fill ••hemselves with blood, (for want, of that ••requent and strenuous compression, for∣merly equal to the influx of the blood,) while the pulse is not so full as ordinarily: ••he hearts left Ventricle not receiving its ••ue supply from the lungs, which in this ••ase receive more than they deliver: Here∣••pon a man is necessitated, (for avoiding ••uffocation) to fetch a great breath, or ••••gh, which may more strongly, than usu∣••lly, compress the substance of the lungs, ••nd reduce them to their former estate. And thus, great attention, any deep con∣templation,

sad thoughts, and a melancho∣lick constitution; do often become the cause of frequent sighing: As also, a natu∣ral 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 abun∣dance, 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 strang∣ling, 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 Re∣spiration. We have, also of consequence, freed the heart, of almost one half of the task imposed on it, by the modern Physiti∣ans. For since the circulation of the blood consists of two parts, viz. First, the con∣veying it from the heart, or center, to the rest of the body, as to a kind of natural circumference. And secondly, the return∣ing, 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 parti∣cular member, to discharge it self of its own superfluities: For which purpose, na∣ture hath endued them with a tone, or to∣nical 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 ••t so much the faster. And so, we shall have entitled the lungs, to one full quarter part, of this work of the circulati∣on 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 Sanguificati∣on, we shall more conveniently find place to consider of, in the following Chapter.

Notes

• inter 1.1

  N. 1.