Veränderungen von Proteus unter hohen Penicillindosen zu Sphäroplasten, die später über amöboide Gebilde zu sogenannten L-Kolonien heranwachsen.

With Proteus the action of higher concentrations of penicillin leads to the formation of the so-called L-phase. First small round structures emerge from the bacterial rods, rapidly enlarging to spheroplasts. These grow into "amoeboid" structures in which vacuoles develop. The spheroplasts multiply and in some places grow deeply into the culture medium where they form the so-called L-colonies. When the penicillin action is suspended there is a gradual regression of the described events and gradually rod-like structures develop again which divide transversely. A stable L-phase may also develop where this regression can no longer occur. Its multiplication is demonstrated. The results of quantitative evaluation are described in detail in the accompanying text.