There were differences in the way the lysogenic strain N of B. mycoides and the parent indicator strain grew on nutrient agar and in nutrient broth.
1. On agar, the indicator culture traveled more quickly over the agar surface than the phage-carrying strain; the total extent of spread was greater.
2. In broth, the indicator strain grew diffusely throughout the liquid, the lysogenic cells in clumps. The virus-infected strain appeared to grow more slowly. This may reflect (a) the effect of aggregation on the generation time of the lysogenic strain, (b) an active lytic process in the lysogenic population which is further enhanced by the effect of clump formation on the environment of the cell.