Nine books of physick and chirurgery written by that great and learned physitian, Dr Sennertus. The first five being his Institutions of the whole body of physick: the other four of fevers and agues: with their differences, signs, and cures.

CHAP. XV. Of the desire and moving faculty.

BEsides the knowing faculty, * 1.1 there is given to man an appetite and force of moving; The Object of mans appetite is good, whether it be really so, or seemingly so. The appetite is two-fold, sensitive and rational: sensitive is that which desires that which seems good to the senses, rational is that which desires that good, that seems so to reason, and the motions of the sensitive faculty are often resi∣sted by the motions of the rational faculty, and there ariseth strife & discord betwixt the sensitive & rational faculty. Out of the appetite, as its actions, arise the affections and passions of the mind, as we call them.

Voluntary Animal motion follows the desire, * 1.2 for after that an ex∣ternal object is brought by the external senses, and common sense to the Phantasie, it is known as profitable, and acceptable, or as hurt∣full,

displeasing. Love, or hatred followeth this knowledge, or th•• desire of what is pleasing, and flight of what is displeasing. Motio•• presently follows the desire in brute beasts, but in man there is t•••• Judgment of the intellective faculty, which values what is truly go•• and what hurtfull. * 1.3 Then the motive faculty follows that motio•• which is commanded by the rational or sensitive faculty, as the o•• or the other over-ruleth, by the contraction of the muscles the ad•• quate Instruments of motion, which draw the tendons, these t•• bones, and they being moved, the members and whole body is ca•• ried from place to place, either to accept of what is grateful, or to re∣sist and fly from what is hurtful.

But although a muscle be the adaequate instrument of motion yet the chiefest part of it consists of fibers or smal strings, * 1.4 which be∣ing contracted, the muscle is contracted and motion performed Although their are four different motions of the muscles, while•• they are contracted, or extended, or moved transverse, or remai•• streight, as Galen says in his first Book of the motion of muscles an•• eighth Chapter, or as others explain it, contraction, conservation o•• contraction or tonick motion, relaxation, and perseveration of re∣laxation: yet contraction only, to which tonick motion belongs, is the proper action of the muscles; but extension which is a passion rather then an action, is not the immediate cause of motion; for whilst a muscle contracted by its opposite muscle is extended, it suf∣fers, it doth not act.

Notes

• * 1.1

  Appetite two-fold, sensitive; rational.
• * 1.2

  Voluntary motion.
• * 1.3

  The motive faculty.
• * 1.4

  The In∣strument of motion.