Abstract
Six strains of C. perfringens representing types A, B, C, D, E, and F were converted to L-forms with the aid of penicillin plate cultures. Reversion was not observed on plate cultures without penicillin but the L-forms reverted to bacterial forms in liquid media. Three types of mature L-colonies of C. perfringens were described. The L-forms were practically nontoxic for guinea pigs and rabbits.