The presence of fluid in the brain was known to ancient physicians. Hippocrates (460-375 BC), when describing congenital hydrocephalus, commented on “water” surrounding the brain [1]. Galen (130-200), the premier anatomist prior to Vesalius (1514-1564), referred to “excremental liquid” in the ventricles of the brain from where it is purged into the nose [2]. Despite the recognition by Hippocrates and Galen of some kind of fluid in the brain, subsequent anatomists missed it for 16 centuries. This was perhaps due to their autopsy technique, ie, cutting off the head from the neck, which drained the cerebrospinal fluid (CSF) and blood from the brain and spine.

The discovery of CSF is attributed to Emanuel Swedenborg (1688-1772), who had graduated from the University of Upsala, Sweden, with a degree in mining and engineering (Fig. 1), Working as a mining engineer, Swedenborg often came across an underground stream of water that lead him to search for its source. As a religious man and a teacher of theology, he took upon himself to search for the seat of the soul. His search for the soul brought him into contact with anatomists in France, Germany, and Italy. Having observed and participated in numerous dissections between 1736 and 1740, he felt prepared to engage in original medical investigations of the brain, which seemed a likely seat of the soul. Swedenborg summarized his observations on the brain, spinal cord, and blood circulation in a manuscript written between 1741 and 1744. Not having medical credentials, he was unable to find a publisher. The manuscript was discovered in