FURTHER STUDIES ON THE SURVIVAL AND DEVELOPMENT IN VITRO OF A MALARIAL PARASITE.

The survival of Plasmodium lophurae in vitro is favored by the presence of calcium pantothenate (0.02 mg. per ml). Survival of about 2 weeks in vitro at 40-41 degrees C. has been obtained under the following conditions: a medium consisting of duck red cell extract in balanced salt solution with glutathione and glucose or glycogen, serum, embryo extract, and calcium pantothenate; daily replacement of about half of the medium with fresh medium; addition of fresh uninfected erythrocytes every 2nd day; gentle agitation of the preparation on a rocking machine. In some of these preparations significant increases in male gametocytes and, more rarely, in total numbers of parasites occurred during the first few days.