Complete inflow stasis of the heart was associated with less central nervous system damage, if the heart was resuscitated with massage. Ventricular fibrillation did not occur during the period of circulatory arrest, but it was seen occasionally after the heart filled. Its incidence was increased by the use of Adrenalin and by allowing the heart to recover without massage. The administration of various doses of heparin had no effect on the Degrees of brain damage resulting from interruption of the circulation.