It is a gram-negative diplococcus. Neisseria lactamica is a gram-negative diplococcus bacterium. He named the bacterium "Diplococcus intracellularis meningitidis". In particular, meningococcus ("Neisseria meningitidis"), a Gram-negative diplococcus organism, releases endotoxin when it lyses. Presumably, diplococcus has been implicated in encephalitis lethargica. Other sources have suggested "Diplococcus" as a cause. These bacteria are gram-negative and diplococcus, rendering them virtually indistinguishable from the other "Neisseria" species. The bacteria Diplococcus has been found to degrade coal, raising its temperature.