Outbursting wedges of the colonies of Clostridium welchii containing chain forming mutants after ultra violet irradiation.

Cl. welchii NCTC 6785 was irradiated with UV light. The 40 minutes irradiated cells after 3-8 days ageing at room temperature (22-25 degrees C) and 48 hours initial incubation at 37 degrees C produced hairy outbursting wedges. These wedges gave rise to the colonies composed of chain forming mutants, which on transfer into the fluid medium grew into a pure chain forming culture.