All those that have been named by me do affirm that the soul itself is incorporeal, and by its own nature is in a perpetual motion, and in its own essence is an intelligent substance, and the actuality of a natural organical body which has life. The followers of Anaxagoras, that it is airy and a body. The Stoics, that it is a hot breath. Democritus, that it is a fiery composition of things which are perceptible by reason, the same having their forms spherical and without an inflaming faculty; and it is a body. Epicurus, that it is constituted of four qualities, of a fiery quality, of an aerial quality, a pneumatical, and of a fourth quality which hath no name, but it contains the virtue of the sense. Heraclitus, that the soul of the world is the exhalation which proceeds from the moist parts of it; but the soul of animals, arising from exhalations that are exterior and from those that are within them, is homogeneous to it. CHAPTER IV. OF THE PARTS OF THE SOUL. Plato and Pythagoras, according to their former account distribute the soul into two parts, the rational and irrational. By a more accurate and strict account the soul is branched into three parts; they divide the unreasonable part into the concupiscible and the irascible. The Stoics say the soul is constituted of eight parts; five of which are the senses, hearing, seeing, tasting, touching, smelling, the sixth is the faculty of speaking, the seventh of generating, the eighth of commanding; this is the principal of all, by which all the other are guided and ordered in their proper organs, as we see the arms of a polypus aptly disposed. Democritus and Epicurus divide the soul into two parts, the rational, which hath its residence in the breast, and the irrational, which is diffused through the whole structure of the body. Democritus, that the quality of the soul is communicated to every thing, yea, to the dead corpses; for they are partakers of heat and some sense, when the most of both is expired out of them. CHAPTER V. WHAT IS THE PRINCIPAL PART OF THE SOUL, AND IN WHAT PART OF THE BODY IT RESIDES. Plato and Democritus place its residence in the whole head. Strato, in that part of the forehead where the eyebrows are separated. Erasistratus, in the Epikranis, or membrane which involves the brain. Herophilus, in that sinus of the brain which is the basis of it. Parmenides, in the whole breast; which opinion is embraced by Epicurus. The Stoics are generally of this opinion, that the seat of the soul is throughout the heart, or in the spirit which is about it. Diogenes, in the arterial ventricle of the heart, which is also filled with vital spirit. Empedocles, in the mass of the blood. There are that say it is in the neck of the heart, others in the pericardium, others in the midriff. Certain of the Neoterics, that the seat of the soul is extended from the head to the diaphragm. Pythagoras, that the animal part of the soul resides in the heart, the intellectual in the head.