The predominating theory in the Island of Cos was that which made health dependent on the exact proportion and play of the elements of the body, and on perfect combination of the four cardinal humors. This was the prevailing doctrine,--i.e., the Ancient Medical Dogmatism, so named because it embraced the most profound dogmas in medicine, and was taught exclusively until the foundation of the school at Alexandria. Two men, however, more commonly ranked among philosophers than among physicians of antiquity, dissected the statements of Hippocrates, and embodied them more or less in their own teachings, and thus exercised a great influence on the progress of the human mind, particularly in the direction of medical study. The first of these was Plato, profound moralist, eloquent writer, and most versatile thinker of his day or any other. He undertook the study of disease, not by observation (the empirical or experimental method), but by pure intuition. He seemed to have never discovered that his meditations were taken in the wrong direction, and that the method did not conduce to the discovery of abstract truths. He gave beauty an abstract{028} existence, and affirmed that all things beautiful are beautiful because of the presence of beauty. This reminds one of that famous response in the school of the Middle Ages to a question: "Why does opium produce sleep?" the answer being: "Because it possesses the sleepy principle." Plato introduced into natural science a doctrine of final causes. He borrowed from Pythagoras the dogma of homogeneity of matter, and claimed that it had a triangular form.