The first Medical and Physical DISCOURSE. Of the growing hot or inkindling of the Blood.
IT is long since I designed to print my Meditations concerning the remaining Pathology of the Brain and Nervous stock: But when many Diseases of that kind affect the animal Spirits, and not rarely the whole Hypostasis of the corporeal Soul more immediately than the Humors or solid Parts; I there∣fore thought it necessary first to publish the Disquisitions of the nature of this Soul, and its manner of subsisting, and also of its Parts and Powers, that from these things rightly known, its preternatural Passions may at length be the better disco∣vered. But concerning these very hard matters, and difficult to be unfolded, when I had begun to frame (as I think) probable and rational Arguments, I saw well that they would be looked upon and laughed at by some as unusual things and Paradoxes; which indeed it becomes me not to take ill, but to let every one freely to enjoy his own sense, and to use in all things his own opinion and judgment. Among the many things conjecturally proposed by me, (which I could not avoid) two chief Arguments are opposed, to wit, that I had affirmed, that the blood for the con∣tinuing of life was inkindled, and that the animal Spirits, for the motive act, were exploded: which terms, though perhaps they may sound rough and strange to be applied to the animal oeconomy; yet if any one shall weigh the Reasons and Ar∣guments which do perswade to the truth of either opinion, I doubt not, but that there will be none who will not give their assent, or easily pardon me for mine. In the first place therefore, because there are so many opinions concerning the growing hot of the Blood, for that some attribute it to an innate heat, others to a flame in the Heart, some also to a fermentation of the bloody mass, and others to its inkind∣ling; therefore I shall endeavour more narrowly to introspect the matter, and as much as I am able, to build upon a more certain Ratiocination, its genuine Cause, though very abstruse.
We have formerly discoursed concerning that Soul, which is common to the more perfect Beasts, with that subordinate or more inferiour of Man, and have shewed it to be indeed Corporeal, and to consist of two parts; the one of these root∣ed in the blood we called a Flame, and the other dwelling in the Brain and nervous stock, Light. As we shall here only treat of the former, I think it will be no difficult matter to make use of the same Reasons and Instances, which truly conclude, or at least very like truth, that in the first place the blood is animate or hath life: second∣ly,