The L-Phase of Erwinia carotovora var. atroseptica and its Possible Association with Plant Tissue

S ummary . The growth and recognition of the L-phase of Erwinia carotovora var. atroseptica in vitro and in vivo is described. Evidence is offered for its existence in nature. It is postulated that the bacterium may be present in the potato plant in such a form, closely associated with the plant tissue cells, and as such may be the means of transmitting the disease from one plant to another without the disease being apparent. Under certain circumstances, as yet undetermined, changes in the environment may lead to the reversion of the L-phase to the bacterial phase with the consequent development of the characteristic disease syndrome.