Abstract
L type cultures have been isolated from a strain of Clostridium tetani with the help of penicillin. Similar cultures were obtained from a freshly isolated unidentified Clostridium when the area surrounding a 2-day-old agar culture was reinoculated with the same strain. The metabolic products diffusing from the old culture inhibited growth and transformed the bacilli into L forms. The L type cultures are similar in appearance to those isolated previously from a Gram-positive spore-bearing bacillus. They differ from the L forms of Gram-negative bacilli inasmuch as they grow better in the absence rather than the presence of animal serum and tend to form large spreading colonies increasing in size for several months.
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