The Influence of the Environment on the Development of Reticularia Lycoperdon Bull.

1. Investigations were made on the influence of temperature electrolytes and osmotic pressure on the development of the endosporic, acalcareous slime-mould, Reticularia Lycoperdon Bull. Experiments were made to investigate the question of the failure of single-cell cultures with the same species. Attempts have been made for pure culture and for mass culture with Reticularia and with some other species of Mycetozoa. 2. The germination of the spores takes place in a temperature range from 2—3o° C. The division of the swarm-cells from 7 26.5° C. The plasmodia-formation from 12—26.3° C. The temperature has great influence upon the rate of the life-processes. The optimum temperature for the germination and for the celldivision was found at about 23° C., when the rate of the process is considered. The optimum for the plasmodia-formation was found at 16—18.3° C., the plasmodia becoming the largest at those temperatures. 3. As to the influence of electrolytes it was found that the cations acted on the germination according to their place in the Hofmeister series. The series for the usual anionic action was found to be reversed. H+ and OH- ions were non-toxic from pH 6—B. The swarmcells when placed in solutions with one salt sometimes formed plasmodia, in other solutions they never fused. The solutions in which plasmodia were formed were: NaCl, KCI, NH4CI, MgCl2, FeCl3, MgS04, Mg(N03)2 and Mgßr2. InCaCl2, BaCl2,CuCl2 and MgC03 plasmodia were never formed. 4. The osmotic pressure limits much the development of this species. In 0.18 mol. solution of saccharose germination has stopped. The swarm-cells and plasmodia are equally sensitive. When placed in 0.2 mol. solution of saccharose they stop their activity, the swarm-cells become rounded off, while the plasmodia are hardened in their habituel form. j. In single-cell cultures made on glass the swarm-cells are damaged by substances which dissolve from the glass. Indications were found that the damaging substance is silica. 6. The results of the culture experiments with Reticularia were negative. Pure cultures were attempted by starting with isolated plasmodia. Growth was never observed in a culture medium containing yeast-autolysate and of Norit. In mass cultures, made in maize decoctions, growth was observed, but the cultures could not be kept under healthy conditions. From the other species tried the pure-culture of Didymium effusum by starting with spores failed, as the spores could not be freed from bacteria. It was cultured in mass-culture on a medium of agar with decoction of maize for about a year. From Stemonitis splendens var. flaccida the pure culture was attempted by starting with spores which had been treated with antiseptics. A multiplication of the swarm-cells was not observed in media of yeastautolysate and maize decoction. Mass-cultures of this species failed.