The Identification and Characterization of Bacteriophages with the Electron Microscope

Abstract

In electron microscope photographs the bacteriophages appear as tiny particles with round head and a longer thin tail. It is interesting that such constant and relatively elaborate structural differentiation should occur in objects of supposedly macro-molecular nature. The result is of equal interest in genetics, since genes, together with viruses, are correctly supposed to be macromolecular entities. The agreement of the particle size with calculations obtained by other methods is significant. The present evidence, together with published results on the irradiation of bacteriophages, indicates the validity of the so-called "hit theory" for the determination of the "sensitive volume" in sub-light-microscopic biological objects. In genetics, too, the "hit theory," although widely criticized, has been used for the calculation of the dimensions of the genes.