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. V. Of Innate Heat.

THat those things may the better be understood which we spake concerning Temperaments, * 1.1 we will say something of primi∣genial heat; for these things are the chief Instruments of the Vege∣tative soul. By the innate heat we do not understand that heat which belongeth to the mixt body, as mixed; but that heat which is proper to living Creatures; the which with the radical moisture is the next and immediate subject and domicil of the Soul, diffu∣sed through all the parts of the body. Nor by heat and moisture do we understand the bare quality, but the quality, with the Subject; to wit, a body hot and moist; the matter namely or Subject wherein heat is, and the quality from whose predominancy the Subject hath its name; to wit, the most pure, subtile, and hottest portion of the si∣milar parts, and especially of the Spermatick parts. This heat is otherwise called both by Physicians and Philosophers, by the name of the within seated spirit, or the native spirit; and it is more con∣veniently called, the within seated spirit, then the innate heat. For although in all the substance be hot; * 1.2 yet heat is not sensibly perceived in all bodies, but onely in living Creatures, and the more perfect of them, which by touching are perceived to be hot.

This Innate heat consists of three things, * 1.3 which make up its ••ssence, Radical moisture, the within seated spirit, and heat; hence ••ernelius defines it to be the Primigenial humidity spread ••rough all the body, by the innate heat and spirit. And these ••ree, Heat, Spirit, and Moisture are linked together by the nearest conjunction in the world; for since that heat ought to be (as it were) Governour and Ruler of our lives, it is onely of an aëricus or spi∣••••ual nature, and so by it self moveable and separable, or apt to be disperst, it could not subsist alone, but that life might be prolonged, 〈◊〉〈◊〉 ought to subsist in a more stable, moist and durable body, more ••ermanent; namely, not a thin and watry body, but a fat and oylie body which is inserted within the fibers of the similar parts, and is called the radical moisture.

Concerning the nature and original of the innate spirit and heat, * 1.4 there is a great controversy amongst Physitians and Philoso∣phers, and 'tis disputable, whether it be Elementary, or of another nature; And although in such an obscure thing, since very learned men disagree, it be very hard to determine any thing, yet I think theirs to be the more probable opinion, who consent with Aristotle in his second Book of Generation of living Creatures, and third Chapter; That Innate heat is not Elementary, nor hath its original from fire or other Elements; nor yet is it of a Heavenly na∣ture, but proportionable to the stability of Stars. For eve∣ry specifical form requires its peculiar domicil and proper subject, and the more noble form requires the more noble habita∣tion, and a more Divine power then Elementary, requires a more noble manfion then a body that is composed of Elements.

Moreover, more noble actions, * 1.5 and Sympathy and Antipathy are in it, which purely from Elements cannot proceed; & again this Innate heat and inborn Spirit, in many Plants is preserved in winter time, and in the midst of frosts safe and secure; Moreover this Innate heat, and radical moisture is founded in the parts which are fashioned in the first generation of an embryon; but the greatest plenty of it is in the heart, which from thence is called by Galen, the fire-fewel of the Innate heat.

This inborn heat, is the chiefest instrument of the soul, * 1.6 by which it perfects, undergoes all the actions of life and whatsoever healthy thing in us, and profitable in generation, in nutriment, or in ex∣pulsion of a disease, is performed by that. From this benefit and excellency of Innate heat, * 1.7 some have taken it and the Soul for the same thing, and have called it the Essence of the vital faculty; the faculty governing us, the substance of the soul, and the Au∣thor of all our actions; but since the Innate heat is neither the

soul, nor the chief cause of our actions, it is onely the chief in∣strument in performing the actions of the soul, in operation, which is not corporal.

This Innate heat doth not remain alwaies the same, * 1.8 but is chan∣ged in the course of our age. For at our first coming into th•• world, it is most, and age increasing, the radical moisture wasted by degrees, and drieth up. So that in the end the radical moi∣sture being clearly gone, the heat also wanting wherewithall to sup∣port it self, goes out, and a natural death followeth.

Notes

• * 1.1

  Innate heat.
• * 1.2

  The In∣nate heat.
• * 1.3

  Whereof the Innate heat con∣sists.
• * 1.4

  Of the original and nature of the In∣nate heat.
• * 1.5

  The sub∣sect of the Innate heat.
• * 1.6

  The use of the Innate heat.
• * 1.7

  The In∣nate soul is not a soul.
• * 1.8

  The chan∣ging of the innate heat