The educational genius of the great university century, the thirteenth, the man who influenced his contemporaries and succeeding generations more than any other, was Thomas Aquinas, to whom the Church, for his knowledge and goodness, gave the title of saint. If any further proof that these centuries were interested in science were needed, or that the universities in which he was the leading light as scholar and professor in the thirteenth century, and as the great master to whom all looked reverentially after, were developing scientific studies, it would be found in {116} his works. Philosophy is developed scientifically in his "Contra Gentes" and theology, scientifically in his great "Summa." It is the very austerity of the scientific qualities of these books that have made them forbidding for many modern readers, who, therefore, have failed to understand the scientific spirit of the time. St. Thomas Aquinas, however, was, as I suggested at the beginning of this, deeply interested in every form of information with regard to what we now call physical science. He evidently drank in with avidity all that had been observed with regard to living creatures and, when we come to analyze his works with care and read his books with the devotion of his own students, we find many anticipations of what is most modern in our science. The indestructibility of matter, matter and form, that is the doctrine of the unity of the basis of matter, the conservation of energy in the sense that the forms of matter change but do not disappear, all these were commonplaces in his thought and teaching. I have recently had occasion to point out how close he came to that thought in modern biology which is probably considered to be one of our most modern contributions to the theory of evolution. It is expressed by the formula of Herbert Spencer, "Ontogeny recapitulates phylogeny." According to this the completed human being repeats in the course of its development the history of the race, that is to say, the varying phases of foetal development {117} in the human embryo, from the single cell in which it originates up to the perfect being as it is born into the world, retrace the history by which from the single-cell being man has gradually developed. The whole theory of evolution is supposed by many people to be modern, but of course it is not. This particular phase of it, however, is thought surely to be modern. It is sometimes spoken of as the fundamental law of biogeny. In recent years serious doubts have been thrown on it, but with that we have nothing to do here.