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of Aristotle and of Hippocrates; and the term that Plato gave to the large vessel—the aorta, is still retained by us; but the knowledge was very confused. The lungs were regarded as an apparatus to cool the heated blood, and to reduce the natural warmth, both emanating from the heart as their source; it was believed that the arteries contained spirit, and that the veins distributed the nourishment collected from the stomach and intestines to the rest of the body. Aristotle declared, that the pulsation of the heart arose from its sudden inflation from new material supplied by the food for fresh formation of the blood. It is difficult for us so to divest ourselves of facts now established and to realize the state of medical knowledge in those early times
But let us turn to another great physician, one who was almost regarded as divine in his unfoldings of the truth of medical science. I refer to Galen, he was born in the year 131 a.d., when the Roman empire had become aroused by the power of Christianity. Galen lived
