consummation, is evolved directly from truths which cannot be translated into terms intelligible to ordinary minds. Newton’s great work influenced neither the morals nor the manners of his age, nor was there any immediate tangible benefit that could be explained to the edification or appreciation of the 1 ordinary man ’ of his day; yet it set forward at a bound the human mind, as did such truths as were proclaimed by Copernicus, by Kepler, by Darwin, and others. In a less conspicuous manner Harvey’s triumph was on the same high plane. There was nothing in it which could be converted immediately into practical benefit, nothing that even the Sydenhams of his day could take hold of and use. Not so much really in the demonstration of the fact of the circulation as in the demonstration of the method—the Inventum mirabile sought for by Descartes, the Novum Organum of Bacon—lies the true merit of Harvey’s work. While Bacon was thinking, Harvey was acting; and before Descartes had left his happy school at La Fleche Harvey was using la nouvelle methode; and it is in this way that the de Motu Cordis marks the break of the modern spirit with the old traditions. No longer were men to rest content with careful observation and with accurate description; no longer were men to be content with finely-spun theories and dreams, which ‘serve as a common subterfuge of ignorance’; but here for the first time a great physiological problem was approached from the experimental side by a man with a modern scientific mind, who could weigh evidence and not go beyond it, and who had the sense to let the conclusions emerge naturally but firmly from the observations. To the age of the hearer, in which men had heard, and heard only, had succeeded the age of the eye, in which men had seen and had been
