Bacillus subtilis, Cohn, and Spirillum undula, Ehrenb.
Spirillum rubrum, Esmarsch.
Spore - formation in O Vibrio- like (c) and o' I O Spirillum-like (a, b, d) o Schizomycetes.
Spirillum containing many spores (a), which are liberated at b by the breaking up of the parent cells.
If the sinuosity is slight we have the Vibrio form; if pronounced, and the spiral winding well marked, the forms are known as Spirillum, Spirochaete, &c. These and similar terms have been applied partly to individual cells, but more often to filaments consisting of several cells; and much confusion has arisen form the difficulty of defining the terms themselves.
Divisions perpendicular to the long axis: - Vibrio (Muller-Ldffler), commashaped, motile, monotrichous; Spirillum (Ehrenb.), more strongly curved in open spirals, motile, lopho trichous; Spirochaete (Ehrenb.), spirally coiled in numerous close turns, motile, but apparently owing to flexile movements, as no cilia are found.
Cohn long ago showed that certain glistening particles observed in the cells of Beggiatoa consist of sulphur, and Winogradsky and Beyerinck have shown that a whole series of sulphur bacteria of the genera Thiothrix, Chromatium, Spirillum, Monas, &c., exist, and play important parts in the circulation of this element in nature, e.g.
Beyerinck has shown that Spirillum desulphuricans, a definite anaerobic form, attacks and reduces sulphates, thus undoing the work of the sulphur bacteria as certain de-nitrifying bacteria reverse the operations of nitro-bacteria.
(1879), p. 28; Beyerinck " Ueber Spirillum desulphuricans, &c.," Cent.