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

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clisstmus. Quartum, Thorn* Bartholin. teste, viro longe celeberrimo, Fran. Sylvio debetur Schel. ubi supr, c. 3. §. 9. 2. Their Difference in Animals: In Man, and Quadrupeds, they are four, curiously 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 Case is very different: His unutn Officulam solitm lar git a est Natura, quod Collumellam forte appellaveris: teres enim eft v fubriliffimum, baft innitens latiori, rotundt. flute adnexa tst cartilago valde mobilis, qut in Tympanum videtur terminari. Id. IU. §. 8. the Bars of all the Fowl that I could examine, I never found atty more than one Bone, and a Cartilage, making a Joynt with it, that was easily moveable. The Cartilage had generally an

Epiphyse, or two, one on each Side. The Bone was -very hard

And small, having at the end of it a broad Plate, of the same Substance, very thin, upon which it rested, as on its Bafts. Dr. Al. Moulen in Phil. Trans. N°. 100.

These are the most material Things I find observed by others, concerning the Ears of Fowls, and some of them hardly, I believe, observed before. To which I shall fubjoyn some other Things I have my self discovered, that 1 prelume escaped the Eyes of those most curious and inquisitive Anatomists. Of which the last cited Book VII. Chap. i. Note (d).

(«) Videtur quod Tympanum Auditionis instrumentum prtliminare, ey quasi prtparatorium fuerit, quod Soni impreffionem, five species senftbiles primo fuscipiens^ eas in debita preportione, rj" apta conformitate, versus Sensorium, quod adhuc interius fitum est, dirigat: fimili officio fttngitur respeftu Audit As, ac tunics, Oculi Pupillam constituentes, respeclu Visus; utreque Membrant Species senftbiles refringunt ejr quasi emolliunt, easque Sensorio non nift proportional as tradunt, cut nudo ft adveniant, teneriorem ejus crafin facile ltdant, aut obruant. Revera Tympanum non audit, fed meliori tutiorique Auditions confers. Si 'me pars destruatur, Senfto adhuc aliquamdiu, rudi licit mode, feragi poffit; quippe experimento olim in Cane faclo, &C—— Janitoris officio ut Tympanum recTe defungi poffit, expansum ejus pro data occasions stringi, aut relaxari debet, veluti nimirum Oculi Pupilla •6)uapropter huh Auris Tympano, nen [ecus

ac bellico, machine five unit qutdam apponuntur, qutsuperficiem ejus modo tenftorem, modo laxiorem reddant: hoc enim effictunt trio. Dfficula, turn Mufculo, &c. WJiM/Ys de Anim. Brut, c. 14.

For From this Region of the tympanum, I might

pass

For this Opinion of Dr. Willis, Dr. Schtlhammer is very severe 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 sonorous Rays are retracted by passing through a different Medium? Whether the Convexity or Concavity of the Drum collects those Rays into a focal Point, or scatters them? we. And then faith, Ob has rationes » clarijs. Viri, ac de re Medico, pr&clari meriti, fententid non pojfumus non else alieniores; in quo uti ingenium admirer, quoties medicamentorum -vires, aut morborum caufas explicat, fie ubi forum fuum egrejjus, Philosophum agit, ac vel Partium usum, vel Chymicarum rerum naturam scrutetur, ejus baud femel non modi judicium defidero, veritm aliquando etiam fidem. This is so severe and unjust a Censure of our truly famous Countryman, (a Man of known Probity) that might deserve a better Answer; but I have only Time to say, that although Dr. Schelhammer hath out-done all that wrote before him, in his Book de Auditu, and shewed himself a Man of Learning and Industry; yet as our Countryman wrote more than he, (though perhaps not free from Errors too) so he hath manifested himself to have been as curious and sagacious an Anatomist, as great a Philosopher, and as learned and skilful a Physician, as any of his Censurers, 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 utr&que Membrane resringunt, Dr. Willis plainly enough, I think, means no more than a Restriction of the Ingress of too many Rays; as his following explicatory Words manifest, viz.. refringunt, v quafi emolliunt, eafque Sensorio non nisi proportionate tradunt. But indeed Dr. Schelhammer hath shewn himself a too rigid Censor, by making Dr. Willis say, the Ear-Drum hath such like Braces as the War-Drum, viz. §»od porro de machinis feu ttniis Tympani bcllici adducit, dicitque idem in Tympano auditorio conspici, id prorsus salfijftmum est. I wonder Dr. Schelhammer did not also charge Dr. Willis with making it a Porter, since 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 straining and relaxing it, as the Braces of the War-Drum do in that. And considering how curious and solemn an Apparatus there is of Bones, Muscles, and Joynts, all adapted to a ready Motiou; I am clearly of Dr. willis's Opinion, that one great

Use Use of the Ear Drum is for rhe proportioning Sounds, and that by its Extension and Retraction, it corresponds to all Sounds, loud or languid, as the Pupil of the Eye doth to several Degrees of Light: And that they are no other than secondary Uses assigned by Dr. Schelbammer, as the principal or sole Uses of keeping out the external colder Air, Dust, and Other Annoyances; but especially that, ob soli us aeris interns fotiffimttm irrumpentis vim, hunc mo turn Tympani ac Mallei tffe conditum, ut cedert primstm, deinde fibi restitui queat; as his Words are, P. ult. c. 6. §. 13.

It was no improbable thought of Rohault, nos at tent os prt,btn, nil aliud est, nisi Tympanum, ubi ha opus est faElo, contender aut laxare, & operam dare ut Mud in ea posttione intentum stet, in qua tremulum aeris externi motum commodifstnie excipere postit. Roh. Phys. p. 1. c. 26. §. 48.

The Hearing of deaf Persons more easily by Means of loud Noises, is another Argument of the Use of the Straining or Relaxation of the Tympanum in Hearing. Thus Dr. Willis (ubi supra) Accept olim a viro fide digno, fe mulierem noviffe, qua licet surda fuerit, quousque tamen intra conclave Tympanum pulsaretur, verba qu&vis dare audiebat: quare Maritus ejus Tympanistam pro servo domeftico conducebat, ut illius ope,. colloquia interdum cum Uxore fua baberet. Etiam de alio Surdastro mihi narratum est, qui prope Campanile degens, quoties unk plures Campant refonarent, vocem quamvis facile audire, <3f non alias, potuit.

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

Upon considering the great Difference in Authors Opinions, about the Use ot" the Parts, and Manner how Hearing is performed, as also what a curious Provision there is made in the Ear, by the four little Bones, the Muscles, Membrane, crc. I was minded (since I penned this Note) to make enquiry my self into this Part, and not to rely upon Authority. And after a diligent search of various Subjects, I find we may give as rational and easie an Account of Hearing, as of Seeing, or any other Sense; as I have (hewn in my last cited Note (d) Book VII. Chap. 2. with relation to Birds. And as to Man and Beasts, the Cafe is the fame, but the Apparatus more complex and magnificent. For whereas in Birds, the auditory Nerve is affected by the Impressions 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 Impressions made upon the Membrana Tympani. Which Impressions are imparted to the auditory Nerve, in this Manner, viz.. First they act upon the Mtmbrant and Malleus, the Malleus upon the incus, and the

Incus

pass to that of the Labyrinth (w), and therein survey the curious and admirable Structure of the Vestibulum, the Semicircular Canals (#), and Cochlea; particularly the artificial Gyrations, and other Angular Curiosities observable in the two latter.

But I shall not expatiate on these recluse Parts j only there is one special Contrivance of the Nerves, ministring to this Sense of Hearing, which must;

■Incus upon the Os Orbiculare and Stapes; and the Stapes upon the auditory Nerve: For the Base of the Stapes (the same as the Operculum in Birds) not only covers the Fenesira Ovalis, within which the auditory Serve Heth, but hath a Part of the auditory Nerve spread upon it too. It is manifest that this is the true Process of Hearing; because, if the Membrane be mov'd, you may see all the Bones move at the fame Time, and work the Base of the Stapes up and down in the Fenestra, Ovalis, as I (hewed in this Chapter, Note id) concerning the Mole; and as it may be seen in other Ears carefully opened, if the Parts remain in fitu.

(w) I do not confine the Labyrinth to the Canales Scmicirculares, or any other Part, as the elder Anatomists seem to have done, who by their erroneous and blind Descriptions seem not well to have understood these Parts; but with those much more curious and accurate Anatomists, Monsieur de Vernay, and Dr. Valfalva; under the Labyrinth, I comprehend the Canales Stmicirculares, and the Cochlea, together with the intermediate Cavity, called by them the Vestibulum.

(x) In the semicircular Canals, two Things deserve to be noted. 1. That the three Canals are of three different Sizes, Major, Minor, and Minimus, i. Although in different Subjects, they are frequently different; yet in the fame Subject they are constantly the fame. The Reason of all which, together with their Uses, Valfalva ingeniously thinks is, that as a Part of the tender auditory Nerve is lodged in these Canals, so they are of three Sizes, the better to suit all the Variety of Tones; some of the Canals suiting some, and others, other Tones. And although (here be some Difference as to the Length and Size of these Canals, in different Persons; yet, lest there fliould be any discord in the auditory Organs of one and the fame Man, those Canals are always in exact Conformity to one another in one and the fame Man. V. Valsal. ubisupr. c. 3. §. 7. and c. 6. §. 4. 9.

not not be passed by, and that is, the Branches of one of the auditory Nerves (>), spread partly to the Muscles of the Ear, partly to the Eye, partly to the Tongue and Instruments of Speech, and inosculated with the Nerves to go to the Heart and Breast. By which Means there is an admirable, and useful Consent between these Parts of the Body } it being natural for most Animals, upon the Hearing any uncouth Sound, to erect their Ears, and prepare them to catch every Sound} to open their Eyes (those constant faithful Sentinels) to stand upon their Watch j and to be ready with the Mouth to call out, or utter what the present Occasion shall dictate. And accordingly it is very usual for most Animals, when surpriz'd, and terrify'd with any Noise, presently to shriek and cry out.

But there is besides this, in Man, another great Use os this nervous Commerce between the Ear and Mouth: And that is, (as one of the best Authors on this Subject expresseth it) (z), "That the Voice "may correspond with the Hearing, and be a kind u of Echo thereof, that what is beard with one u of the two Nerves, may be readily expressed "with the Voice, by the help of the other.

(y) Hicpofierior Nervus extra cranium delatus, in tres ramos dividitur, qui omnes motibus patheticis inserviunt. Pri

mtw mttsculis Auris impenditur. Proculdubio hujus adi

*ne efficitur, ut animalia qu&vis, a subito font impulsu, aures, quasi sonum nimis cito tranfeunttm captaturas erigant. Ramus alter —— versus utrumque oculi angulum furculos emittit: qui mufculis palpebrarum attollentibus inseruntur; quorum terse munus est ad fubitum font appulfum oculos confestim apeTire, eofque velut ad Excubias vocare. Tertius —— ramut versus Lingua radicem dejeendens, mufculis ejus w offis Hyoeideos distribuitur,adeoque organa qu&dam vocts edendt acluat, &c Willis's Cereb. Anar. c. 17.

(x) Hujusmodi Rervorum consormatio in Homine usum ahum msignhrem pr&stat, nempt ut Vox, 8cc, Willis Ibid,

Thus

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