The bacterium, Clostridium pasteurianum, common in most soils, is able to utilize free nitrogen under anaerobic conditions, and an organism known as Azotobacter chroococcum and some others closely allied to it, have similar powers which they can exercise under aerobic conditions.
Schizomycetes such as Clostridium, Plectridium, &c., where the sporiferous cells enlarge, bear out the same argument, and we must not forget that there are extremely minute " yeasts," easily mistaken for Micrococci, and that yeasts occasionally form only one spore in the cell.
Various stages in the development of the endogenous spores in a Clostridium - the small letters indicate the order.
Clostridium - one cell contains two spores.
Germination of spore of Clostridium butyricum - the axis of growth coincides with the long axis of the spore.
Sporogenous rodlets, spindle-shaped: - Clostridium (Prazm.), motile (peritrichous).
Laurent and others were right, and that Clostridium pasteurianum, for instance, if protected from access of free oxygen by an envelope of aerobic bacteria or fungi, and provided with the carbohydrates and minerals necessary for its growth, fixes nitrogen in proportion to the amount of sugar consumed.
Amylobacter can ferment cellulose, and the case of mud bacteria which evolve sulphuretted hydrogen below which is utilized by sulphur bacteria above has already been quoted, as also that of Winogradsky's Clostridium III.