From meningitis in man, encephalitis in cattle and sheep, a myocardial infection in fowl, and a generalized infection in rabbits, different observers have isolated Gram-positive organisms which are closely related. Their cultural and serological properties are described. When injected intravenously into chickens, rabbits, or guinea pigs there is an unusual blood response, the monocytes being markedly increased. The organisms tend to localize in the myocardium with resulting necrosis.