the earliest known description of the role of air in circulation was produced in egypt in 3500 bce. at this time, egyptians believed that the heart was the origin of many channels that connected different parts of the body and transported air as well as urine, blood, and the soul. the edwin smith papyrus (1700 bce), named for american egyptologist edwin smith (1822 - 1906 ce) who purchased the scroll in 1862, provided evidence that egyptians believed that the heartbeat created a pulse that transported the above substances throughout the body. a second scroll, the ebers papyrus (c. 1550 bce), also emphasized the importance of the heart and its connection to vessels throughout the body and described methods to detect cardiac disease through pulse abnormalities. however, despite their knowledge of the heartbeat, vessels, and pulse, the egyptians attributed the movement of substances throughout the vessels to air that resided in these channels, rather than to the heart's force. the egyptians knew that air played an important role in circulation, but they did not yet have a concept for the precise role of the lungs.