SYSTEMATIC AND DESCRIPTIVE. 



319 



grow readily on fleshy roots, old cheese, etc. They 

 convert the lactic acid in milk into butyric acid, 

 and produce the ripening- of cheese. They occur 



FIG. 124. CLOSTRIDIUM BUTYRICUM. 



A. Active stage, (a, b) Bent rods (vibrio-form) and threads. (V) Short rods. 



(d) Long rods. 



B. Spore-formation. C. Spore-germination. [After Prazmowski. ] 



also in solutions of starch, dextrine, and sugar, 

 and are the active agents in the fermentation of 

 sauerkraut and sour gherkins. 



