An Anomalous Meningococcus

Extract

(1) An unusual strain of meningococcus has been isolated which produces minute “dew drop” colonies. This character has persisted throughout a large number of successive generations. Every culture, however, has shown lateral off-shoots consisting of colonies which have the size and appearance of those of typical meningococci. In subsequent subcultivations from these colonies the newly acquired size and appearance remain constant.

(2) It is suggested that the strain isolated is a retrograde variety and that the off-shoots are produced by degressive evolution.

(3) It is also suggested that the character which reappears in the degressive step is that of producing a substance beneficial for growth.

It is impossible, however, to offer any satisfactory explanation of the phenomena observed without a more extended series of experiments. This was impracticable at the time owing to pressure of routine work and further observations on the same organism have now become impossible owing to the fact that the small growing strain has died out. Nevertheless the findings seem worth recording in their present state in the hope that they may be of use to others who have met or may meet with similar peculiarities in the course of their work.