The Process of Transformation of Antigenic Type in Paramecium Aurelia, Variety 4.

initiate it may likewise be unique. At least, gene-initiated plasmagenes can be more readily assimilated into current genetic knowledge and theory which demand ultimate gene control of hereditary capacities. The cells of a multicellular organism are like the cells of a clone of unicellular organism in .their presumed identity of genes. Nevertheless, in both the Metazoan and the Protozoan persistently diverse types of cells arise. In Paramecium, our analysis indicates that persistent diversity of traits may arise as a result of environmentally produced quantitative differences among a series of alternative plasmagenes. The same mechanism may therefore be suggested as the basis of cellular differentiation in higher organisms. If this turns out to be correct, control of cellular transformation in tissue cultures and in normal and abnormal development is indicated, and genetics has moved a step closer to its necessary ultimate fusion .with experimental embryology.