15 

 SUMMARY. 



With a not too limited species-conception Clostridium polymyxa, Granulobacter 

 polymyxa, Bacillus macerans, and Bacillus asterosporus may be brought to one single 

 species : Ba<^ill^s polymyxa. 



It is the only hitherto known aerobic spore-former, which, in neutral sugar- 

 containing media excites fermentation and thereby proves able to live as a temporary 

 anaërobe. 



The chief products of the fermentation are carbonic acid and alcohol. At the 

 aerobic life a little aceton results, evidently from oxidation of sugar. 



Anaërobic accumulation is possible in rye paste at 30° C. after short boiling. 

 Aerobic accumulation takes place in dilute malt-wort or broth with 2% to 5% sugar, 

 after heating at 85° to 90° C. or short boiling with much garden soil and cultivation 

 at 15° C. by which B. mesentericus is excluded, whose growth minimum is at about 

 20° C. 



The general distribution of B. polymyxa in decayed plants and its occurrence in 

 the bark of plant roots and of the nodules of the Leguminosae reposes on the produc- 

 tion of pectinase, which dissolves the central lamellum of the cellular tissues. 



B. polymyxa forms much slime from sugar, which must be considered as cell-wall 

 substance. Without carbohydrates or polyalcohols its growth seems impossible, hence 

 it develops but slightly on broth agar. 



The slime may serve as reserve food. 



Laboratory for Microbiology of the Technical 

 High School at Delft. 



