And moreover, as the Form of this Organ is various in various Animals, so in each of them its Structure is very curious and observable, being in all admirably contrived to collect the wandering, circumambient Impressions, and Undulations of Sound, and to convey them to the Sensory within. If I should run over the several Genera of Animals, we might find a notable Prospect of the handy-work of God[e], even in this so inconsiderable Part of Animals. But I shall only carry my Survey to that of Man. And here the first Thing that offereth it self to our View, is the Helix, with its tortuous Cavities, made to stop, and collect the sonorous Undulations, to give them a gentle Circulation and Refraction, and so convey them to the Concha, or larger and more capacious round Cell at the Entrance of the Ear. And to bridle the Evagation of the Sound, when arrived so far, but withal not to make a Confusion thereof, by any disagreeable Repercussions, we may take notice of a very curious Provision in those little Protuberances, called the Tragus, and Antitragus of the outward Ear, of a commodious Form and Texture[f], and conveniently lodged for this Use. The great Convenience and Benefit of this Form and Contrivance of the outward Ear, is sufficiently manifest by the want thereof, which causeth a Confusion in the Hearing, with a certain Murmur, or Swooing like the Fall of Waters[g].
Another wise Provision of the Creator, is in the Substance of the outward Ear, which is cartilaginous, the fittest for this Place. For (as an ingenious Anatomist[h] observes) “If it had been Bone, it would have been troublesome, and might by many Accidents have been broken off: If Flesh, it would have been subject to Contusion”. But indeed a worse Consequence than this would have ensu’d such a Softness as that of Flesh, and that is, it would neither have remain’d expanded, neither would it so kindly receive and circulate the Sounds, but absorb, retard, or blunt their Progress into the inward Organ. But being hard, and curiously smooth and tortuous, Sounds find an easie Passage, with a regular Volutation and Refraction: As in a well-built Arch, Grotto, or musical Instrument, which magnify and meliorate Sounds; and some of which convey even a Whisper to a large Distance[]: But from the outward, let us carry our Survey,
2. To the inward Part of this admirable Organ. And here we find the most curious and artful Provision for every Emergency and Occasion. The auditory Passage, in the first Place, curiously tunnelled, and artfully turned, to give Sounds an easie Passage, as well as a gentle Circulation and Refraction; but withal, so as to prevent their too furious rushing in, and assaulting the more tender Parts within.
And forasmuch as it is necessary that this Passage should be always open, to be upon the Watch[k]; therefore to prevent the Invasion of noxious Insects, or other Animals, (who are apt to make their retreat in every little Hole), Nature hath secured this Passage[l], with a bitter nauseous Excrement[m], afforded from the Glands[n] appointed for that Purpose.
From hence let us approach the most inward Parts, in which we shall see Strokes of the most exquisite Art. To pass over the innate Air, that most Authors talk of[o], (because there is no such) the passage to the Palate[p], and their Uses, with divers other curious Things that might be named; let us stop a little at the Part containing the rest, namely, the Bone[q]. The particular Texture and Hardness of which, above other Bones of the Body, is very remarkable; whereby it serves not only as a substantial Guard to the Sensory, but also to oppose the Impulses of the ætherial Matter, that there may be no loss, nor Confusion in the Sound; but that it may be conveyed regularly, and intirely to the auditory Nerves.
The next Part I shall take Notice of, may be that fine Membrane, called the Tympanum, or Membrana Tympani[r], with its inner Membrane[]; together with the four little appendent Bones[t], and the three inner Muscles to move them, and adjust the whole Compages to the several Purposes of Hearing, to hear all Manner of Sounds, loud or languid, harsh or grateful[].
From this Region of the Tympanum, I might pass to that of the Labyrinth[w], and therein survey the curious and admirable Structure of the Vestibulum, the Semicircular Canals[x], and Cochlea; particularly the artificial Gyrations, and other singular Curiosities observable in the two latter.