Abstract
In a previous report (Cole and Glees, 1956) on methyl-phenidate (Ritalin) as an antagonist to reserpine (Serpasil) in monkeys we referred to a similar effect produced by amphetamine. Following up this work we have now studied and compared the effects of methyl-phenidate and amphetamine when given separately without reserpine to normal and leucotomized monkeys.