x] BACILLI : SPECIAL i8i 



growth. On potato it forms a thick, whitish, creamy growth 

 rapidly covering the inoculated surface ; here, as also on 

 fluid media, it forms copious spores in a resistant, corrugated 

 surface-pellicle. 



In hay-infusion (neutralised) that had been kept in the 

 incubator at 37" C. the spores which appear are not all 

 belonging to the bacillus subtilis ; those in the surface- 

 pellicle are spores of this bacillus, but in the depth of the 

 fluid spores occur which resemble the above in aspect, 

 shape, and size, but which belong to the bacillus amylo- 

 bacter or bacillus butyricus of Prazmovski, a strictly 



^ w 



Fig. 54. — Germination of Spores into Bacilli. 

 a Spores of a small kind. 

 b. Spore-s of a larger kind of bacillus subtilis. 

 Magnifying power about 700. 



anaerobic motile bacillus liquefying grape-sugar gelatine. 

 Aerobic gelatine plates made of such an infusion, or of the 

 surface-pellicle, after heating to 8o''C. from five to ten minutes, 

 bring forth the colonies of the hay-bacillus only. Anaerobic 

 cultures in grape-sugar gelatine made of the fluid taken 

 from the bottom yield growth of the bacillus amylobacter ; 

 the chief morphological character distinguishing it from the 

 hay-bacillus and from other anaerobic bacilli {e.g. bacillus 

 butyricus of Hueppe and of Botkin) is its change in shape 

 during sporing ; the cylindrical bacilli, as spores develop and 

 grow in them, change into spindle- or tadpole-shaped 

 forms three and more times thicker around the spore — 

 Clostridium. 



