224 AGEICULTUEAL AND INDUSTRIAL BACTERIOLOGY 



bound and sunk in water of a pond or stream. Certain ana- 

 erobic bacteria closely related to the clostridia already 

 noted as bringing about cellulose fermentation find con- 

 ditions favorable for growth under these conditions and 

 produce pectinase, dissolving and digesting the binding 

 elements between the bundles of bast fibers. Several species 

 have been described as instrumental in bringing about this 

 cnange. The ones most commonly noted are Clostridium 

 asterosporum and Clostridium pectinovorum. "When the 



FIG. 53. CLOSTRIDIUMS. 1. Clostridium butyricum. 2. Clostridium 

 pectinovorum. 



process has continued sufficiently long and before these 

 microorganisms attack the cellulose, the bundles are re- 

 moved, dried and are ready for the extraction of the bast 

 fibers which can now be readily accomplished by mechanical 

 means. In the aerobic process the flax or hemp is allowed 

 to lie on the surface of the ground exposed to the dew and 

 rain. Under these conditions certain molds and possibly 

 certain bacteria as well, grow through the stems and 

 gradually bring about the same kind of change as in water 

 retting. It may be noted that pure cultures of anaerobic 

 retting bacteria have been prepared and their use has 

 proved successful in an experimental way. 



FERMENTATION OF STARCH AND INULIN 

 Starch and inulin are two of the most commonly formed 

 polysaccharides stored as reserve food material by plants. 



