THE INFLUENCE OF H-ION CONCENTRATION ON THE SPORULATION OF B. WELCHII

It is well known that B. Welchii does not sporulate readily. When grown in ordinary culture media scanty spore production is usually noted even after prolonged incubation. This applies particularly to media containing a fermentable carbohydrate even though in very small amount. The literature contains few studies on the environmental factor or factors which determine sporulation on the part of this organism. Such reports as have been made would suggest that the reaction of the substrate exercises the controlling influence. Grassberger and Schottenfroth in 1900 reported that the sporulation activity of their anaerobic immobile butyric acid bacillus was increased by alkalinity in the medium and that the optimal degree of alkalinity varied with different strains. Some of these strains may not have been B. Welchii as the species was not adequately identified at that time. Noguchi in 1907 employed a sugar-free bouillon with an alkalinity ranging from N/50 to N/75 NaOH as a basic medium and added various carbohydrates in 1 per cent amount. He found that if acidity was produced by the growth of B. Welchii no spores were formed. Fitzgerald in 1911, working with Noguchi and using his methods, confirmed in general his findings. She concluded that the optimal alkalinity zone for spore formation ranged from N/200 to N/50 NaOH, that the presence of NaCl in the medium, ranging from 0.5 to 5 per cent, was not a factor influencing spore formation but that the presence of certain unfermented carbohydrates in the basal medium, especially mannitol and amylodin, enhanced spore formation while even in the presence of acid formed from