Morphological appearances of various stages in B. proteus and coli

Abstract

It has been shown that in all cultures of B. proteus and B. coli a large-cell type with two to four ‘chromosomes’ develops first and produces, after a few hours of growth, by sudden subdivision the smallest unit, a generation of small cells, each with one nuclear structure only. This cell type, singly or in filaments, persists until the end of the growing period. On a ‘swarming plate’ of B. proteus a number of these biphasic growing periods may follow each other.‘Fusion cells’, in which the chromatinic structures have contracted into a longitudinally arranged bar, are formed when young cultures are stored in the cold.