The Morphology of the Mycobacteria

Abstract

The growth of 3 species of Mycobacterium; namely a hitherto undescribed sapro-phytic species isolated at the Univ. of Wisconsin, the timothy bacillus, and the avian tubercle bacillus, was observed microscopically. Division occurred only by binary fission. Branching forms were not seen even at magnifications of 1425 times. The cells were not uniform in size or shape. Coccoid and relatively long rod forms were seen to be functions of the ratio of the rate of division to the rate of growth in length. Bent rods, club-shaped rods, and such types result from the flexibility of the walls of young cells and the growth pressures from other cells.