The Role of Methæmoglobin on the Leptomonad Phase of Leishmania Tropica, with Special Reference to Its Reversion into Leishmania Forms in Culture

In a former communication one of us (Row, 1922) had pointed out that the flagellate leptomonad forms of Leishmania tropica reverted to the leishmania O-bodies and these made their appearance in the condensation fluid of NNN culture tubes inoculated with the parasite 2 to 3 weeks previously. These were described as the O-bodies, or resistant forms, and it is the presence of these in old cultures of L. tropica which was responsible for their infectivity in mice?even to the extent of inducing a generalized infection in them?indistinguishable from experimental kala-azar (Row, 1914). The observation on the infectivity of old cultures containing these resistant forms was confirmed by Southwell and Kirshner (1938)*. It was also pointed out (Row, 1922) that the reversion was due either to the concentration of the fluid