my endeavour to show that these judgments are historically justifiablec.
To put the discovery of the systemic circu- lation of the blood in its true light, we must have some notion of the history of philosophy, science and medicine. Medicine, and herein it is in contrast with Theology and Law, had its sources almost wholly in the Greeks. Not only in the doctrine of the four elements of Empedocles, a doctrine which has survived almost to our own day, and in the physical theories of Heraclitus and Leucippus, did medicine, for good or ill, first find a scheme of thought, but in the schools of Hippocrates and of Alexandria it was based also, and far more soundly, upon natural history and anatomy. The noble figure of Galen, the first experi- mental physiologist and the last of the great Greek physicians, portrayed for us by Dr Payne in the Harveian Oration of 1896, stood eminent upon the
¹ The "humoral doctrine" is imperfectly known. The four elements are earth, water, air, firo; the four qualities are hot, cold, moist, dry; the four humours are blood, phlegni, yellow bile, black bilc. By permutation of these were obtained the endless elaborations of the galenist doctrine which for many conturies blinded Europe not to the truth only, but also to the clinical and physiological methods, example, and attain- ments of Galen himself,
