Abstract Rivers, Sprunt and Berry (1) and Rivers and Schwentker (2) induced lesions in the central nervous system (CNS) of the monkey by numerous injections of suspensions and alcoholic extracts of rabbit brain. Ferraro and Jervis (3) confirmed and extended these studies. Morgan (4) produced encephalomyelitis in rhesus monkeys by a few injections of suspensions of brain and spinal cord of monkeys combined with killed tubercle bacilli, paraffin oil and an emulsifying agent. Independently, Kabat, Wolf and Bezer (5) using the same technique obtained almost identical results in monkeys but stated that similar experiments carried out in guinea pigs and white mice were negative. In their study, neurologic symptoms were produced in 2 monkeys after a single injection. It seemed desirable to ascertain whether this type of encephalomyelitis could be produced in the guinea pig.