British physician William Harvey (1578–1657) publishes his theory on the circulation of the blood. Others, like Wepfer (1620–1695), still believe that apoplexy is caused by an obstruction in the path to the brain, suggesting that the brain did not receive enough "animal spirits". G.G.J. Robinson theorizes that there is a "plethora of fulness of blood", therefore bleeding is acceptable since it lessens the pressure on the "animal organs".