top, to fence against all Annoyances; its cartilaginous Rings (6) nearly environing it, with its membranous Part next the Gullet, to give the freer Paffage to the defcent of the Food; and laftly, its inner Tegument of exquifite Senfe to be readily affected with, and to make Efforts against every thing that is hurtful or offenfive, thefe, I fay, do all juftly deferve our Admiration.

And no lefs prodigious are the Parts farther within; the Bronchi, the Veficula (7), with their mufca

lar

branous. And in a Pigeon, which hath a low and foft Note, 'tis partly Cartilaginous, and partly Membranous. In an Owl, which hath a good audible Note, 'tis more Cartilaginous. But that of a Jay, hath hard Bones, inftead of Cartilages; and fo of a Linnet:. whereby they have both of them, a louder and fironger Note, &c.

The Rings of the Wind pipe are fitted for the Modulation of the Voice. For in Dogs and Cats, which in the Expreffion of divers Paffions use a great many Notes, (as Men do,) they are open and flexible, as in Man. Whereby all, or any of them are dilated, or contracted, more or less, as is convenient for a higher or deeper Note, &c. whereas in fome other Animals, as in the Japan-Peacock, which ufeth hardly more than one fingle Note, they are entire, &c. Grew's Cofmolog. Sacr. Book 1. Chap, 5. §. 9, 10.

(6) It is a farther manifeft Indication of fingular Defign in the cartilaginous Rings of the Afpera Arteria, that all the way where they are contiguous to the Oefophagus, they are Membranous, to afford an eafie Paffage to the Food; but after that, in the Bronchi; they are fome compleatly-Annular, fome Triangular, . And another obfervable is, the lower Parts of the fuperior Cartilages, receive the upper Parts of the inferior, in the Bronchi; whereas in the Aspera Arteria, the Cartilages run and remain parallel to one another which is a noble difference or Mechanism in this (in a manner) one and the fame Part, enabling the Lungs and Bronchi to contract themselves in Expiration, and to extend and dilate themselves in Infpiration.

(7) I fhall not here intrench To much upon the Anatomift's Province, to give a Description of the Lungs, although it be a curious Piece of God's Workmanship, but refer to Seignior Malpighi, the first Discoverer of their Veficula in 1660, in his two Letters to Borelli de Pulmon. Alfo to Dr. Willis's Pharm. rat.

lar Fibres (†), as fome affert they have, together with the Arteries and Veins, which every where accompany the airy Paffages, for the Blood to receive there its Impregnations from the Air.

From

p. 2. S. I. c. 1. de Refpir. Orig. & US who as he wrote after Malpighi, fo hath more accurately described those Parts; and to Mr. Cowper's Anat. Tab. 24. 25. And if the Reader hath a mind to fee what Oppofition Seignior Malpighi's Discoveries met with at Home and Abroad, and what Controverfies he had on that account, as also his Cenfures of Dr. Willis's Descriptions and Figures, he may confult Malpighi's Life written by himself, pag.4.

to 21.

.

That the Lungs confift of Vehicule, or Lobuli of Veficula admitting of Air from the Bronchi is vilible, because they may be blown up, cleanfed of Blood, and fo dried. But Mr. Comper faith, he could never part the Lobuli, (fo.as to make Dr. Willis'š Fig. 1. Tab. 3. & 4.) fo that probably the Veficula are contiguous to one another throughout each Lobe of the Lungs. And not only Air, but Diemerbroeck proves, that the Veficula admit of Duft alfo, from two Afthmatick Perfons he opened; one a Stone-Cutter's Man, the Veficula of whofe Lungs were fo ftuffed with Duft, that in cutting, his Knife went as if through an heap of Sand. The other was a Feather-Driver, who had thefe Bladders filled with the fine Duft or down of Feathers

(†). There is a confiderable difference between Dr. Willis, and Etmuller, viz. whether the Veficula of the Lungs have any mufcular Fibres or not? Etmuller exprefly faith, Nullas Fibras mufculofas, multo minus rubicundam Mufculorum compagem (funt enim Veficula albida & fere diaphane) in ipfis reperiri. ubi fupr. c. 6. §. 2. And afterwards, §. 3. Pulmones effe molles flexilefque mufculofis fibris ceu propria explicationis organis deftitutos. But Dr. Willis as exprefly afferts they have mufculous Fibres, and affigns an excellent Ufe of them; Cellula ifte veficulares, ut nixus pro expiratione contractivos edant, etiam fibras, uti per Microfcopium plane confpicere eft, musculares obtinent. ubi fupr. §. 16. And in the next 9, Ut pro datâ occafione majorem aeris copiam exfufflent, aut materiam extuffiendam ejiciant, fibris mufcularibus donate, fefe arctius contrahunt, contentaque fua penitus exterminant. Etenim ordinaria pectoris Syftola, quas mufculorum relaxationes ex parte efficiunt, aerem forfan totum à Trachea & Bronchiis, haud tamen à Veficulis, quaque vice ejiciunt: propter has (quoties opus erit) inaniendas, & totius Peltoris cavitas plurimùm anguftatur,

From hence I might proceed to the commodious Form of the Ribs (8), the curious Mechanism of the Intercoftal-muscles (9), the Diaphragm, and all the other Muscles (10) miniftring both to the or dinary, and extraordinary Offices of Refpiration. But

cellula ipfa veficulares à propriis fibris conftri&is coarƐlantur. (8) Circa hos motus [Scil. Pectoris dilatationem, &c.] divini Conditoris mechanicen, ad regulas Mathematicas plane adaptatam, fatis admirari non poffumus; fiquidem nullâ aliâ in re manifeftius O has greater videtur. Quippe cum pectoris túm ampliatio, Θεὸς γεωμετρῶν tum coarctatio à quibufdam Mufculis (quorum munus unicum eft contrahere) perfici debeat; res ita inftituitur, ut Cofta qua thoracis, velut parellelogrammi oblongi versus cylindrum incurvati, latera efformant, in figuram modo quadratam, cum angulis rectis, pro pectoris ampliatione; modo in rhomboeidem, cum angulis acutis pro ejufdem contra&tione, ducantur, &c. Willis, ubi fupr. §. 28.

Galen having spoken of the parts miniftring to Refpiration, concludeth, Nihil usquam à Naturâ ullo pacto per incuriam fuiffe præteritum, quæ cùm omnia præfentiret,& provideret, qua funt neceffaria illa, que caufa alicujus extiterunt, confecutura, omnibus inftaurationes parare occupavit, cujus apparatus copiofa facultas admirabilem Sapientiam teftantur. De uf. part. 1. 5. c. 15. See also l. 6. c. I.

1

(9) For the Structure of the Intercoftals, Midriff, &c. I fhall refer to Dr. Willis, and other Anatomifts. But Dr. Drake taxetli Dr. Willis with an Errour in fancying there is an oppofition in the Office of the Intercoftals, by reason that the Fibres of the external and internal Intercoftals decuffate; that therefore the External serve to raise the Ribs, the Internal to draw them down. But Dr. Drake is of Steno's, and Dr. Mayow's Opinion, that notwithstanding the Decuffation of their Fibres, the Power they exert upon, and the Motion they effect in the Ribs is one and the fame. Drake's Anat. 1. 2. c. 7. and 1.4. C. 5. Mayor de Refpir. c. 7.

(10) Although Dr. Drake and fome others deny the Intercoftals being Antagonist-Mufcles, as in the preceding Note, yet they, and most other Anatomifts that I have met with, attribute a confiderable power to them in the act of Refpiration, as they do alfo to the Subclavian, and Triangular Mufcles learned Etmuller denies it for these three Reasons, I. Quia refpirando nullam in illis contractionem fentio. 2. Quia

but the

fibi in

But paffing them by, I fhall ftop at one prodigious Work of Nature, and manifeft Contrivance of the Almighty Creator, which although taken notice of by others (11), yet cannot be eafily paffed by in the Subject I am upon; and that is the Circulation of the Blood in the Fatus in the Womb, fo different from the Method thereof after it is Born. In the Womb, whilft it is as one Body with the Mother, and there is no Occafion, nor Place for Refpiration, there are two Paflages (12) on purpofe for the tranfmiffion of the Blood without palling it through the Lungs.

pivem non adducuntur, &c. 3. Quia Cofta omnes ab aliis modo enarratis mufculis moventur, idque fimul, &c. Intercostales itaque, necnon Subclavios Mufculos Coftis, parietum inftar, ad complenda imerftitia intercoftalia, pectufque integrandum, ac Coftas connectendas, intertextos effe, probabilitèr concludo; quo munere Triangulares etram -fungi, rationi confentaneum eft. Etmul. Differt. 2. .cap. 4. §. 6.

But as to the Ufe of the Triangular Mufcle in Respiration, we may judge of it, from its remarkable Size, and Ufe in a Dog; of which Dr. Willis gives this Account from Fallopius In Homine parvus aden & fubtilis ifte [Mufculus] eft, ut vix pro Mufcula accipi queat in Cane per totum os pectoris protenditur, & cartilagines omnes, etiam verarum Coftarum fterno inoftulatas, occupat. Cujus difcriminis ratio divinam circa Animalium fabricas Providentiam plane indigitat. Quippe cum hoc animal, ad curfus velociffimos & diu continuandos natum, quo fanguis, dum intenfius agitatur, ritè accendatur eventileturque, aerem celerrimè & fortiter uti infpirare, ita etiam exfpirare debet-idcirco propter hunc actum firmiùs obeundum (cujus in Homine baud magnus eft ufus) mufculus caninus molem ingentem & tanto operi parem fortitur. Willis ubi fupr. §. 32.

(11) Ray's Wisdom of God in the Creation, p. 343.

(12) Mr. Chefelden, an ingenious and moft accurate Anatomift, having fomewhat particular in his Obfervations about the Circulation of the Blood through the Heart of the Foetus, I fhall prefent the Reader with fome of his Obfervations, which he fa voured me with the fight of. The Blood (faith he) which is brought to the Heart by the afcending Cava, passeth out of the right Auricle into the left; through a Paffage called Foramen Ovale, in the

Septum

Lungs. But as foon as the Fatus is Born, and become thereby a perfectly diftinct Being, and breathes for it felf, then these two Paffages are fhut up: one nearly obliterated, the other becomes only a Ligament, except in fome Creatures that are Amphibious, or are forced to lie long under Water, in whom these Paffages probably remain open (13).

And now what Action of any rational Creature, what is there in a Man's Life, that doth more plainly

Septum [common to them both] without paffing through the right Ventricle (as after the Birth) while the Blood from the defcending Cava paffeth through the right Auricle and Ventricle into the pulmonary Artery, and thence into the Aorta through the Duct, betwist that and the pulmonary Artery, called Ductus Arteriofus, whilft a fmall Portion of the Blood, thrown into the pulmonary Artery paffeth through the Lungs, no more than is fufficient to keep open the pulmonary Veffels. Thus both Ventricles are employed in driving the Blood through the Aorta to all Parts of the Fatus, and to the Mother too. But after the Birth, the Blood being to be driven from the Aorta through the Fatus alone, and not the Mother too, one Ventricle becomes fufficient, whilft the other is employed in driving the Blood through the Lungs, the Ductus Arteriofus being fhut up by means of the Alteration of its Pofition, which happens to it from the raising the Aorta by the Lungs when they become inflated. After that the Blood is thus driven into the Lungs, in its return it shuts the Valve of the Foramen Ovale against the Foramen it felf, to whose fides it foon adheres, and fo stops up this Paffage. The Ductus Arteriofus, or Ductus Arteriofus in Ligamentum verfus, is feldom to be difcerned in adult Bodies, but the Figure of the Foramen Ovale is never obliterated.

(13) It hath been generally thought to be not improbable, but that on fome Occafions the Foramen Ovale may remain open in Man. In a Girl of four or five Years of Age, Dr. Connor found it but half closed, and in the Form of a Crefcent. And he thinks fomewhat of this kind might be in the Person whofe Skeleton was found to have no Joynts in the Back-bone, Ribs, c. Of which a Defcription, with Cuts, may be found in Phil. Trans. Nr. 215. and more largely in his Differt. Med. Phyf. de fupendo Offium coalitu, where he adds to the Girl, in whom the For. Op. was not fhut, a like Observation of another Girl he opened at Oxford of three Years Old, in qua Foramen Ovale ferè

erat