Galenicae Quaestiones Disputatae Duae: rete mirabile and pulmonary circulation.

The author discusses two points of Galenic medicine that have long interested medical historians: why did Galen describe a non-existent arterial rete mirabile at the base of the human brain and was Galen the first to discover the pulmonary circulation. After reviewing the evidence, it is concluded that Galen mistook the venous rete mirabile at the base of the human brain for an arterial one and that he indeed described the passage of blood from the right to the left ventricle although he did not discover the pulmonary circulation.