"The innate fire is not in the right ventricle," a Hippocratic author had written, who had written also that the wall of the left ventricle is dense, to guard the strength of the heat.[112] Aristotle, too, had placed in the heart the "origin" of the "natural innate heat";[113] had likened the heart to "the hearth on which shall lie the natural kindling, well protected also, as being the acropolis of the body."[114] At a later day Galen had affirmed the same doctrine.[115] Let us turn now to the famous treatise of 1628, published twelve years after the note-book had been written. In the chapter in which Harvey says "I tremble lest I have mankind at large for my enemies" and then publishes and names the circulation,--in this chapter, before passing to his proofs, he published the following words which resound in a way very different from the simplicity of the note-book:-- "So probably it may come to pass in the body through the movement of the blood that all the parts are nourished, cherished, quickened, by the hotter, perfected, vaporous, spirituous, and, so to speak, alimentive blood; that the blood, on the other hand, is cooled, coagulated, and rendered, as it were, effete in the parts; whence it returns to its origin, namely, the heart, as to its fountain, or the hearth of the body, to regain perfection. There by the potent and fervid natural heat, a treasury of life, as it were, the blood is liquefied anew and becomes pregnant with spirits and, so to speak, with balsam. Thence the blood is distributed again; and all this depends upon the motion and pulsation of the heart. "The heart, therefore, is the origin of life and the sun of the microcosm, even as the sun in his turn might well be called the heart of the world; by the vigor and pulsation of the heart the blood is moved, perfected, quickened, and delivered from corruption and thickening; and the function of nourishing, cherishing, quickening the entire body is performed by that intimate hearth, the heart, the foundation of life, the author of all. But of these matters more conveniently when I shall speculate as to the final cause of motion such as this."[116] Upon this florid passage follow the classic six chapters which bring forward with such power and calm the proofs of the circulation. These are succeeded in their turn by words which echo their sobriety, as follows:--