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Morphological Effects of Penicillin on Bacteria


WHILE working with Chain, Florey and others on the inhibition of bacterial growth by penicillin1, I noticed that concentrations of less than full inhibiting power caused a change in the appearance of the growth of Cl. welchii in fluid media. The normal uniform turbidity was replaced by a flocculent growth with a heavy deposit. Microscopical examination showed an extreme elongation of the majority of the cells, which took the form of unsegmented filaments ten or more times longer than the average normal cell.

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  1. Lancet, 226 (1940).

  2. Brit. Med. J., 2, 16 (1904).

  3. J. Inf. Dis., 64, 59 (1939).

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GARDNER, A. Morphological Effects of Penicillin on Bacteria. Nature 146, 837–838 (1940).

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