Knowledge of the circulation before William Harvey.

O UR present understanding of the function of the circulatory system began to emerge from the confusion of ancient writings scarcely 300 years ago. Yet thousands of years before, man had wondered about the pulsations of the heart and blood vessels. The records of many of these speculations have been preserved and, though often fragmentary and distorted in translation, they tell the story of one of the first discoveries in the science of physiology. Some of the conceptions of the cardiovascular system held before Harvey's clear formulation of the circulation of the blood in 1628 are presented here, and the environment that promoted the growth of these earlier ideas is considered. The first explanations of natural phenomena were based on supernatural forces, and the mysteries of the body were understood in terms of the greater mysteries of the gods. Since the questions raised in primitive societies, both ancient and contemporary, found a ready answer in mythology, there was little incentive for investigation into the workings of the body. The dependence of scientific thought upon the cultural environment can be seen in the writings of ancient Egypt and Mesopotamia. Unlike the records of the contemporary Meso-potamians, the papyri of Egypt are surprisingly free of references to magic and gods, and represent an attempt to understand the functions and illnesses of the body in natural rather than supernatural terms. This secular attitude reflected the position of the physician in ancient Egypt, for though the Egyptian physician received the privileges and titles of the priesthood as did his Mesopotamian counterpart , he was able to remain quite independent of the great temples. Even the administration of the Egyptian medical schools was often in the hands of physicians rather than 726 priests. As a result, Egyptian medicine developed in the shelter of the priesthood without being subverted by the mystical and demonia-cal beliefs that dominated the medicine of the Mesopotamians. The earliest known reference to the heart and circulation is in the Edwin Smith papyrus, transcribed in the seventeenth century B.C., but based on observations recorded as long ago as 3000 B.C. Here is found the statement: "Now if ... any physician put his hands or his fingers upon the head, upon the two hands, upon the pulse, upon the two feet he measures the heart because its vessels are in the back of the head and in the pulse; and because its pulsation …