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QVEST. XLI. Of the manner of Hearing.
COncerning the manner of Hearing the Phylosophers doe diuersly dissent in their opinions.
Alcmaeon thought that we doe therefore Heare because our Eares are empty and hollow within, for all empty things doe make a resonance.
Diogenes thought that there was a kind of Ayre within the Braine, and that this Ayre was strucken with the voyce, & this conceit was controuerted in Hippocrates times, & ther∣fore in his booke 〈 in non-Latin alphabet 〉〈 in non-Latin alphabet 〉, he inueigheth against it; There are (saith he) some which writing of the Nature of things haue affirmed that the braine doth make a sound, which cannot be, for the Braine is humide and moyst, but no moyst body can cause a sound. Plato writeth that Hearing is made by the pulsation and beating of an internall Ayre.
But we passing by these slippery wayes of opinions will insist vpon the true manner of Hearing, and in a short and familiar discourse display the whole Nature thereof. For be∣cause the Organ of Hearing was vnknowne to the antient Phylosophers and Physitions, particularly to Aristotle and Galen in whose dayes Anatomy was but in the infancie and therefore the many small and curious parts of that Organ not found out; we cannot there∣fore collect the perfect nature of Hearing out of their writings, and therefore in this disqui∣sition we must trust more vnto our owne experience.
Aristotle in his second booke de anima and in his booke de sensu & sensili, saith, that three things are required vnto sense.
The obiect, medium and instrument or Organ, the obiect of the Hearing is Sound, as colour is the obiect of the light, but of the Nature of a sound, wee haue intreated already as much as is necessary for this place. Onely I will call to your remembrance by the way, that a Sound is a quality arising from the fraction and breaking of the Ayre which is made by the percussion of two hard and solide bodyes, for soft things doe easily yeeld, nei∣ther doe they resist the force of that which beates against them.
The medium or meane of Hearing is the externall Ayre, for Aristotle doubted whe∣ther a voyce could be heard in the water or no, and yet he knows very well that Fishes do heare who was euer present at the fishing for Mullets in the night.
The instrumtnt of the Hearing is not the external Eare, but the internall, which con∣sisteth of foure cauities and many other particles vnknowne to the Antients.
The manner therefore of Hearing is thus. The externall Ayre beeing strucken by two hard and solid bodyes, and affected with the qualitie of a sound doth alter that Ayre which adioyneth next vnto it, and this Ayre mooueth the next to that, vntill by this conti∣nuation and successiue motion it ariue at the Eare. For euen as if you cast a stone into a pond there will circles bubble vp one ouertaking and moouing another: so it is in the per∣cussion of the Ayre; there are as it were certaine circles generated, vntil by succession they attaine vnto the Organ of Hearing. Auicen very wittily calleth this continuation of the strucken Ayre vndam vocalem, a vocall waue.
But this kind of motion is not made in a moment but in succession of Time, where∣vpon it is that the sound is not presently after the stroke, heard from afarre. The Ayre en∣dowed with the quality of a sound is through the auditory passage, which outwardly is al∣wayes open, first striken against the most drie and sounding membrane, which is therefore called Tympanum or the Drumme. The membrane being strucken doth mooue the three little bones, and in a moment maketh impression of the character of the sound. This sound is presently receiued of the inbred Ayre, which it carryeth through the windowes of the stony stone before described, into the winding burroughs, and so into the Laby∣rinth, after into the Snaile-shell, and lastly into the Auditory Nerue which conueyeth it thence vnto the common Sense as vnto his Censor and Iudge. And this is the true man∣ner of hearing.