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CHAP. XXXVIII. Of the sound and the voyce.
IT is sufficiently manifest by that which we haue said, that the voyce is an action of the Larinx, and that it is the instrument of the voyce, and that * 1.1 the glottis or whistle is the first and immediate cause of the voyce and this is Galens opinion, wherefore we will discourse a little of the voyce.
The voyce therefore according to Aristotle is a certaine significatiue sound of a liuing creature, or as Galen defines it, the voyce is the Ayre * 1.2 strucken, and a sound is the percussion of one body against another in some other. There be therefore three things required to the effecting of a sound, to wit, two seuerall bodyes which doe mutually strike one another, & the ayre in which the purcussion is made, which ayre is beaten and broken betwixt the two bodies.
But that these bodyes thus mutually knocking one another, may effect a sound, first, * 1.3 it is required that they be stretched, by which tension or stretching they are somewhat har∣dened, therefore Aristotle supposed that they ought to be hard, for a sponge & wooll may mutually strike one another and yet no sound be made. But if you say that sounds are ofte∣ner made by hard bodyes, yet it is true also that sometimes they are made by soft bodyes, for if you ioyne your lips together a kind of whistling may be heard, but this proceedeth from their tension whereby they thrust out the Ayre by compressing each other.
Moreouer, they ought to haue a broade and plaine superficies, for two needles stri∣king * 1.4 one another doe make no sound. Againe, the percussion ought to be vehement and quicke, for if you gently put your hand to any thing no sound is heard. But if besides, these * 1.5 bodyes be polished and concauous or hollow, and of a solid and ayry matter, such as brasse and glasse is, then the sound will be greater, more plaine and delightsome, which may bee shewed in bels and musical instruments for such bodyes containe a great deale of ayre in them, which airy when it is moued and seeketh a vent, doth euery way strike about the sides and euery way causeth a resonance or resounding.
Now seeing a voyce is the sound of a liuing creature, or a certaine species or kind of * 1.6 sound; there must be euen so many things required to it as a sound. Namely, the aire for the matter, the bodyes which by compressing the ayre doe as it were breake it for the efficient cause; & we may adde the place which is the head of the rough Arterie. * 1.7
The ayre which is required for the forming of a voyce is that which we returne by expiration, and this is the matter for the generating of a voyce; for that which is inspired is prepared for the refreshing and nourishment of the heart and Inbred heate. Wherefore a mans voce is so long continued as the expiration endureth, and when it fayleth the voyce vtterly ceaseth. Now this expired aire is broken by by the ayry instrument and so the voyce is formed at this breaking, and where it is broken there percussion doth forthwith follow. But it may be demanded which of the ayry instruments can strike and presse this ayre.
The Chest and the lungs do not make this voyce, because their motions be Diastole * 1.8 and Systole or dilatation and constriction which make no voyce. Neither is it the pipe of the Rough Arterie or the greatest part of the weazon because it wanteth muscles: where∣fore it cannot perfect the voyce which is a voluntary worke.
Moreouer, if you cut the weazon below the Larinx or head, the creature will yet expire * 1.9 freely, but he will not vtter any voyce: and if againe you bind this incision the voyce will re∣turne. Neither is it the nosthrils which is the cause of the voyce, because they are onely passage, nor the mouth because it is onely a receptacle, nor the tong because they which be dumbe haue their tongs and respiration sound; so they which haue their tongue cut out doe yet vtter some kind of voyce. It remaineth therfore that amongst the ayry instruments onely the Larinx or throtle is it which is as it were, the shop or worke-house wherein the percussion is made, which the fabricke and structure of it do sufficiently shew.
For it hath Muscles which are necessarily required to the effecting of a voyce which is a voluntary action: It hath also nerues which affoord the motion, Gristles also which are hard bodyes, broade, smooth, polished and concauous or hollow, vpon which the ayre may easily be broken, constringed and compressed and therwithall resound. It hath also a cleft which is requisite vnto the breaking of the ayre that so a sound may be made. For this breaking of the ayre cannot be done vnles it passe through by some straight & narrow way * 1.10
This Elision or breaking is made through the cleft when it is constringed and angustated or straightned by the articulation of the Arytaenoides or Ewre-gristle and the Muscles.