Nonmotile Variants of Bacillus alvei.

The ability of Bacillus alvei to form migrating colonies upon the surfaces of solid media free from excessive moisture was reported previously by Smith and Clark (1938).2 A similar property has been noted by Roberts (1935) for Bacillus rotans. Recently Shinn (1938), in a cinematographic study of colony motility of B. alvei, remarked that it was surprising that such motility had been so long overlooked, and questioned whether the phenomenon applied to B. alvei or to a bacterium described as "Bacillus helixoides" by Muto (1904). Following our original demonstration of colony motility in B. alvei, additional cultures, isolated from foulbrood of bees and labelled B. alvei or Bacillus para-alvei have been received which likewise show colony migrations. All of our own isolates from soil, considered identical with named cultures of B. alvei, have shown motile colonies. Reports of earlier workers (Cheshire and Cheyne, 1885; Harrison, 1900; White, 1906; Tarr, 1935) upon B. alvei contain descriptions of its growth upon solid media which suggest that the phenomenon of colony motility had occurred, even though the actual migration had not been observed. Such references, together with the motility of authentic cultures, have led to the present study to determine whether colonies of B. alvei always show motility under suitable conditions.