Mikrokosmographia a description of the body of man. Together vvith the controuersies thereto belonging. Collected and translated out of all the best authors of anatomy, especially out of Gasper Bauhinus and Andreas Laurentius. By Helkiah Crooke Doctor of Physicke, physitian to His Maiestie, and his Highnesse professor in anatomy and chyrurgerie. Published by the Kings Maiesties especiall direction and warrant according to the first integrity, as it was originally written by the author.

QVEST. XIX. What the Medium ought to be and of what kinde.

AFter we know which of the Senses doe need a Medium it followeth that wee make inquiry to find out what this Medium is & how it ought to be affected. And herein we must first obserue that the Medium ought alwayes to be pre∣sent; least when all thinges else requisite for Sense bee fitly disposed, yet for fault of a Medium we bee made lesse able to performe this act of Sensation. VVherefore the Medium by whose interposition wee Perceiue is not Fire, for this is not al∣wayes * 1.1 at hand but Ayre, for this doeth alwayes encompasse vs about, it is alwayes present, in it we leade our liues.

Secondly, this medium should alwayes consist in a middle place betwixt the Organ * 1.2 and the obiect, for hence it hath the name of a medium, yet so, that it touch both the Or∣gan and the obiect, for otherwise it could not performe his office. But there is no Ele∣ment which is continually contiguous with our Organs but the Ayre. Thirdly, it is ne∣cessary

that this medium be voyde of all sensible qualities, for otherwise it would bring the obiect adulterated or defiled to the Organ and affect the Sense with a proper quality of * 1.3 his owne: VVherefore no compounded body is fit for this function, because all compoun∣ded things are sensible of themselues.

If you obiect that there be no Elements exquisitely pure, and that therefore none of them can be a fit medium being themselues sensible. I grant indeede that no Element * 1.4 that is neere vs is perfectly pure, yet that Ayre that is neere vs wherein we liue doth ex∣ceed the rest in puritie, and is cleare from all qualities except Tactile, so that it may be ac∣counted for a medium to all the rest of the Sense except the Touch.

And is there then one medium seruing to all the Senses?

Yea, for this is the conclusion which is inferred from the former premises, to wit, be∣cause this alone is most pure, and is alwayes present with vs, this alone is continu∣ally in the middest betweene the Organ and the obiect, this is alwayes close adioyning and touching both the Organ and the obiect. The Ayre therefore alone serueth for a medium to the Sight as it is Traculent; to the Hearing as it is sounding; to the Smell as it is capable of odours.

But it may be obiected, that if the Ayre be the onely meane of the Senses, then would it follow that Fishes which liue in the water haue no Sense.

I answer, that for their sight the water serueth for a medium, but other Senses they haue none (saith Placentinus) sauing their Tast and Touch, and these two haue neede of a medium, yet they haue these Senses also but imperfect; but if any man will yet more in∣stantly vrge, that they haue the Sense of hearing, we grant they may heare but most imper∣fectly, and for such imperfect sensation the water serues in steed of a medium; but we speak here of perfect Sensation, where as the Sensation of Fishes is not simply perfect, but on∣ly in their owne kind, to wit, so farre foorth as they haue need of it.

Lastly, this condition of the medium is required to the perfect performance of Sense, namely, that it bee not too spatious or ample, and also that it bee not too narrow or little. But what is the limit or extent of this medium, that is, how farre or wide it ought to extend * 1.5 it selfe, is impossible to be determined, for this limit or extent must almost infinitely be va∣ryed according to the magnitude, paruity and vehemency, as also according to the vigor & strength, or imbecillity and weakenesse of the Sense: For we doe not discerne Mountains, Cities and whole Countryes but a farre off, and lesser things wee do not see except they be neere at hand. So we doe not perfectly and without offence to the Organ heare a vehe∣ment sound, except there bee a great distance betwixt the Sence and the obiect; nor a low voyce except we be neare vnto it. And the same reason is of the rest.

Notes

• * 1.1

  Fire is not the Medium, but Ayre.
• * 1.2

  2. Reason why the Ayre is the Medium
• * 1.3

  The conditiō of a Medium.
• * 1.4

  agreeth with no element except Ayre.
• * 1.5

  The termina∣tion of the medium is di∣uers.