Effect of the Method of Presentation of the Medium on the Germination and Growth of Single Spores of Bacillus subtilis

S ummary . Micromanipulation of single spores on an agar surface allowed the observation of normal and heat damaged spores in microculture. In tests for viability on different media, spores recorded as 'dead' in some media were fully viable when nutrients were supplied by diffusion from agar cylinders. In microculture of heat-damaged spores, only those phase-bright spores which exhibited considerable delay in becoming phase-dark were eventually capable of forming visible colonies. Rapidly germinating spores were incapable of any outgrowth, except for a small minority which developed to a maximum of 4–8 cells and then lysed.