The Significance of Bacterial Variation

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Abstract
16 variant forms of a strain of M. tetragenus originally isolated from a patient were classified into 5 specific types with their respective culture-phases and 2 unclassifiable forms. They were grown under a variety of adverse conditions to determine whether or not evidence could be obtained to support the view that microbic variation is a purposeful attempt on the part of the bacterium to adjust itself to a new and changed environment. While the various types seemed to fall into 2 groups in regard to ability to grow at high temps. on the one hand, or low temps. on the other, or in acid or alkaline media and in other respects, no evidence was obtained to show that variation was induced in the direction proper to continue existence of the strain. Variants seemed to appear more or less by chance. It was assumed therefore that if by chance a variant suited to a new and changed environment were present at the proper time, life would be continued by this form. To this extent then microbic variation, especially type transformation, seems to be a phenomenon which permits the continued existence of the strain of M. tetragenus under a wide range of environmental conditions.