of Hearing, to hear all Manner of Sounds, loud or languid, harsh or grateful (u).

From

Etiffimus. Quartum, Thoma Bartholin. tefte, viro longè celeberrimo, Fran. Sylvio debetur Schel. ubi fupr. c. 3. §. 9. 2. Their Difference in Animals: In Man, and Quadrupeds, they are four, curioufly inarticulated with one another; with an external and internal Muscle to draw, or work them, in extending, or relaxing the Drum; but in Fowls the Cafe is very different: His unum Officulum folùm largita eft Natura, quod Collumellam fortè appellaveris: teres enim eft & fubtiliffimum, bafi innitens latiori, rotunda. Huic adnexa eft cartilago valde mobilis, qua in Tympanum videtur terminari. Id. Ib. §. 8. the Ears of all the Fowl that I could examine, I never found any more than one Bone, and a Cartilage, making a Joynt with it, that was easily moveable. The Cartilage had generally an Epiphyfe, or two, one on each Side. The Bone was very hard and fmall, having at the end of it a broad Plate, of the fame Subftance, very thin, upon which it refied, as on its Basis. Dr. Al. Moulen in Phil. Tranf. No. 100.

in

These are the moft material Things I find observed by others, concerning the Ears of Fowls, and fome of them hardly, I believe, obferved before. To which I fhall subjoyn fome other Things I have my felf difcovered, that I prefume escaped the Eyes of thofe most curious and inquifitive Anatomifts. Of which the last cited Book VII. Chap. 2. Note (d).

(u) Videtur quòd Tympanum Auditionis inftrumentum praliminare, & quafi praparatorium fuerit, quod Soni impreffionem, five fpecies fenfibiles primo fufcipiens, eas in debitâ proportione, apta conformitate, versus Senforium, quod adhuc interiùs fitum eft, dirigat: fimili officio fungitur refpectu Auditus, ac tunica Oculi Pupillam conftituentes, refpectu Visus; utraque Membrana Species fenfibiles refringunt & quafi emolliunt, eafque Senforio non nifi proportionatas tradunt, cui nudo fi adveniant, teneriorem ejus crafin facile ladant, aut obruant. Reverà Tympanum non audit, fed meliori tutiorique Auditioni confert. Si bac pars deftruatur, Senfio adhuc aliquamdiu, rudi licèt modo, peragi poffit; quippe experimento olim in Cane facto, &c.Janitoris officio ut Tympanum rectè defungi poffit, expanfum ejus pro datâ occafione ftringi, aut relaxari debet, veluti nimirùm Oculi Pupilla- -Quapropter huic Auris Tympano, non fecus ac bellico, machina five tania quadam apponuntur, qua fuperfi ciem ejus modò tenfiorem, modò laxiorem reddant: hoc enim efficiunt tria officula, cum Mufculo, &c. Willis's de Anim. Brut.

C. 14.

For

From this Region of the Tympanum, I might

pafs

For this Opinion of Dr. Willis, Dr. Schelhammer is very fevere upon him, deriding the Refractions he speaks of; and therefore seriously proves that they are the Humours, not Tunicks of the Eye, that refract the Rays of Light; and then jeeringly demandeth, Whether the fonorous Rays are refracted by paffing through a different Medium? Whether the Convexity or Concavity of the Drum collects thofe Rays into a focal Point, or fcatters them? &c. And then faith, Ob has rationes à clariss. Viri, ac de re Medicâ praclarè meriti, fententiâ non poffumus non effe alieniores; in quo uti ingenium admiror, quoties medicamentorum vires, aut morborum caufas explicat, fic ubi forum fuum egreffus, Philofophum agit, ac vel Partium ufum, vel Chymicarum rerum naturam fcrutetur, ejus haud femel non modò judicium defidero, verùm aliquando etiam fidem. This is fo fevere and unjust a Cenfure of our truly famous Countryman, (a Man of known Probity) that might deferve a better Anfwer; but I have only Time to fay, that although Dr. Schelhammer hath out-done all that wrote before him, in his Book de Auditu, and fhewed hinfelf a Man of Learning and Induftry; yet as our Countryman wrote more than he, (though perhaps not free from Errors too) fo he hath manifefted himfelf to have been as curious and fagacious an Anatomift, as great a Philofopher, and as learned and skilful a Physician, as any of his Cenfurers, and his Reputation for Veracity and Integrity, was no less than any of theirs too. But after all this terrible Clamour, Dr. Schelhammer prejudicately mistaketh Dr. Willis's Meaning, to fay no worse. For by utraque Membrana refringunt, Dr. Willis plainly enough, I think, means no more than a Restriction of the Ingrefs of too many Rays; as his following explicatory Words manifeft, viz. refringunt, & quafi emolliunt, eafque Senforio non nifi proportionatas tradunt. But indeed Dr. Schelhammer hath fhewn himself a too rigid Cenfor, by making Dr. Willis fay, the Ear-Drum hath fuch like Braces as the War-Drum, viz. Quod porrò de machinis feu teniis Tympani bellici adducit, dicitque idem in Tympano auditorio confpici, id prorfus falfiffimum eft. I wonder Dr. Schelhammer did not alfo charge Dr. Willis with making it a Porter, fince he faith in the fame Paragraph, Janitoris officio, &c. But Dr. Willis's Meaning is plain enough, that the little Bones and Muscles of the Ear-Drum do the fame Office in ftraining and relaxing it, as the Braces of the War-Drum do in that. And confidering how curious and folemn an Apparatus there is of Bones, Muscles, and Joynts, all adapted to a ready Motion; I am clearly of Dr. Willis's Opinion, that one great

Ufe

Ufe of the Ear Drum is for the proportioning Sounds, and that by its Extenfion and Retraction, it correfponds to all Sounds, loud or languid, as the Pupil of the Eye doth to feveral Degrees of Light: And that they are no other than fecondary Ufes affigned by Dr. Schelhammer, as the principal or fole Ufes of keeping out the external colder Air, Duft, and other Annoyances; but especially that, ob folius aeris interni potiffimùm irrumpentis vim, hunc motum Tympani ac Mallei effe conditum, ut cedere primùm, deinde fibi reftitui queat; as his Words are, P. ult. c. 6. §. 13.

It was no improbable thought of Robault, nos attentos prebere, nil aliud eft, nifi Tympanum, ubi ita opus eft facto, contendere aut laxare, & operam dare ut illud in eâ pofitione intentum ftet, in quâ tremulum aeris externi motum commodissimè excipere poffit. Roh. Phyf. p. 1. c. 26. §. 48.

The Hearing of deaf Perfons more eafily by Means of loud Noifes, is another Argument of the Ufe of the Straining or Relaxation of the Tympanum in Hearing. Thus Dr. Willis (ubi fupra) Accepi olim à viro fide digno, fe mulierem novisse, qua licèt furda fuerit, quoufque tamen intra conclave Tympanum pulfaretur, verba quavis clarè audiebat: quare Maritus ejus Tympaniftam pro fervo domeftico conducebat, ut illius ope,> colloquia interdum cum Uxore fuâ haberet. Etiam de alio Surdaftro mihi narratum eft, qui prope Campanile degens, quoties unà plures Campana refonarent, vocem quamvis facilè audire, non aliàs, potuit.

Abfciffo Mufculo [Proceffus majoris Mallei] in recenti aure, relaxatur [Tympani Membrana]. Valfalv. de Aur. Hum. c. 2. §. 5.

Upon confidering the great Difference in Authors Opinions, about the Ufe of the Parts, and Manner how Hearing is performed, as alfo what a curious Provifion there is made in the Ear, by the four little Bones, the Mufcles, Membrane,

c. I was minded (fince I penned this Note) to make enquiry my felf into this Part, and not to rely upon Authority. And after a diligent fearch of various Subjects, I find we may give as rational and eafie an Account of Hearing, as of Seeing, or any other Sense; as I have fhewn in my last cited Note (d) Book VII. Chap. 2. with relation to Birds. And as to Man and Beafts, the Cafe is the fame, but the Apparatus more complex and magnificent. For whereas in Birds, the auditory Nerve is affected by the Impreffions made on the Membrane, by only the Intermediacy of the Collumella; in Man, it is done by the Intervention of the four little Bones, with the Muscles acting upon them; his Hearing being to be adjusted to all kinds of Sounds, or Impreffions made upon the Membrana Tympani. Which Impreffions are imparted to the auditory Nerve, in this Manner, viz. Firft they act upon the Membrane and Malleus, the Malleus upon the incus, and the

pafs to that of the Labyrinth (w), and therein furvey the curious and admirable Structure of the Vefiibulum, the Semicircular Canals (x), and Cochlea; particularly the artificial Gyrations, and other fingular Curiofities obfervable in the two latter.

But I fhall not expatiate on these reclufe Parts; only there is one fpecial Contrivance of the Nerves, miniftring to this Senfe of Hearing, which must

•Incus upon the Os Orbiculare and Stapes; and the Stapes upon' the auditory Nerve: For the Bafe of the Stapes (the fame as the Operculum in Birds) not only covers the Feneftra Ovalis, within which the auditory Nerve lieth, but hath a Part of the auditory Nerve spread upon it too. It is manifest that this is the true Procefs of Hearing; because, if the Membrane be mov'd, you may fee all the Bones move at the fame Time, and work the Bafe of the Stapes up and down in the Feneftra Ovalis, as I fhewed in this Chapter, Note (d) concerning the Mole; and as it may be feen in other Ears carefully opened, if the Parts remain in fitu.

(w) I do not confine the Labyrinth to the Canales Semicir culares, or any other Part, as the elder Anatomifts feem to have done, who by their erroneous and blind Defcriptions feem not well to have understood these Parts; but with those much more curious and accurate Anatomifts, Monfieur de Vernay, and Dr. Valfalva; under the Labyrinth, I comprehend the Canales Semicirculares, and the Cochlea, together with the intermediate Cavity, called by them the Veftibulum.

(x) In the femicircular Canals, two Things deserve to be noted. 1. That the three Canals are of three different Sizes, Major, Minor, and Minimus. 2. Although in different Subjects, they are frequently different; yet in the fame Subject they are conftantly the fame. The Reafon of all which, together with their Ufes, Valfalva ingenioufly thinks is, that as a Part of the tender auditory Nerve is lodged in these Canals, fo they are of three Sizes, the better to fuit all the Variety of Tones; fome of the Canals fuiting fome, and others, other Tones. And although there be fome Difference as to the Length and Size of thefe Canals, in different Perfons; yet, left there should be any difcord in the auditory Organs of one and the fame Man, thofe Canals are always in exact Conformity to one another in one and the fame Man. V. Valfal ubi fupr. c. 3. §. 7. and c. 6. §. 4. 9.

not

not be paffed by; and that is, the Branches of one of the auditory Nerves (y), fpread_ partly to the Muscles of the Ear, partly to the Eye, partly to the Tongue and Inftruments of Speech, and inofculated with the Nerves to go to the Heart and Breaft. By which Means there is an admirable, and useful Confent between thefe Parts of the Body; it being natural for moft Animals, upon the Hearing any uncouth Sound, to erect their Ears, and prepare them to catch every Sound; to open their Eyes (thofe conftant faithful Sentinels) to stand upon their Watch; and to be ready with the Mouth to call out, or utter what the prefent Occafion fhall dictate. And accordingly it is very usual for moft Animals, when furpriz'd, and terrify'd with any Noife, presently to fhriek and cry out.

But there is befides this, in Man, another great Use of this nervous Commerce between the Ear and Mouth: And that is, (as one of the beft Authors on this Subject expreffeth it) (z), "That the Voice

may correfpond with the Hearing, and be a kind "of Echo thereof, that what is beard with one "of the two Nerves, may be readily expreffed "with the Voice, by the help of the other.

(y) Hic pofterior Nervus extra cranium delatus, in tres ramos dividitur, qui omnes motibus patheticis inferviunt. Primus mufculis Auris impenditur. Proculdubio hujus actione efficitur, ut animalia quavis, à fubito foni impulfu, aures, quafi fonum nimis citò tranfeuntem captaturas erigant. Ramus alter verfus utrumque oculi angulum furculos emitit: qui mufculis palpebrarum attollentibus inferuntur; quorum certè munus eft ad fubitum foni appulfum oculos confeftim aperire, eofque velut ad Excubias vocare. Tertius verfus Lingua radicem defcendens, mufculis ejus & offis Hyoeideos diftribuitur, adeóque organa quadam vocis edenda actuat, &c. Willis's Cereb. Anat. c. 17.

ramus

(z) Hujufmodi Nervorum conformatio in Homine ufum alium infigniorem praftat, nempe ut Vox, &c. Willis Ibid.

Thus