We find in this philosopher many indications that the vascular system was in some degree beginning to be understood.[352] Mr. Lewes and Mr. Grote agree that Diogenes deserves a higher place in the evolution of philosophy than either Hegel or Schwegler. EMPEDOCLES of Agrigentum, born about 490 B.C., now bears forward the flaming torch of medical science, and in his hands it burns more brightly still. Aristotle mentions him among the Ionian physiologists, and ranks him with the atomistic philosophers and Anaxagoras. These all sought to discover the basis of all changes and to explain them. According to Empedocles: “There are four ultimate kinds of things, four primal divinities, of which are made all structures in the world—fire, air, water, and earth. These four elements are eternally brought into union, and eternally parted from each other, by two divine beings or powers, love and hatred—an attractive and a repulsive force which the ordinary eye can see working amongst men, but which really pervade the whole world. According to the different proportions in which these four indestructible and unchangeable matters are combined with each other is the difference of the organic structure produced; _e.g._, flesh and blood are made of equal parts of all four elements, whereas bones are one-half fire, one-fourth earth, and one-fourth water. It is in the aggregation and segregation of elements thus arising that Empedocles, like the atomists, finds the real process which corresponds to what is popularly termed growth, increase, or decrease. Nothing new comes or can come into being; the only change that can occur is a change in the juxtaposition of element with element.”[353] He considered that men, animals, and plants are demons punished by banishment, but who, becoming purified, may regain the home of the gods. It is hardly necessary to say that he held the demoniacal possession theory of disease, and treated all complaints by means appropriate to the theory. Anticipating the modern opinions of the bacteriologists, he banished epidemics by building great fires and draining the water from marshy lands. He understood something of the causes of infectious diseases, and in their treatment usurped the province of the gods who had sent them.[354] He believed the embryo was nourished through the navel. We owe to him the terms _amnion_ and _chorion_ (_i.e._, the innermost and outer membranes with which the fœtus is surrounded in the womb). He believed that death was caused by extinction of heat, that expiration arose from the upward motion of the blood, and inspiration from the reverse. He is said to have raised a dead woman to life.[355]