There exist but fragments of the Pre-Socrat- ics, and Xenophon's Memoirs of Socrates contain scant notice of biology or physics. Recently it has been recognized that a mine of suggestion, if not information, as to the early Greek thoughts upon the working of Nature in living organisms is to be found in that large and most significant body of medical and even biological literature which trails the authorship of Hippocrates. He was Socrates' contemporary; and although it is difficult to prove his authorship of any one of these treatises, a goodly part are from the fifth century, when he lived, and are convincingly associated with the great physician to whom they are ascribed. Other portions of the Hippocratic corpus are affected by the theories of the natural philosophers, and reflect contemporary conceptions of Nature.
For example: "Hippocrates speaks of Nature as arranging the vitals in the inner parts; says of the auricles of the heart that they are instruments by which she takes in the air, adding that they seem to be the handiwork of a good craftsman; refers to the vis medicatrix naturae, Nature having discovered the methods without understanding and untaught;
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