94 



HIGH TEMPEBATUEE ORGANISM OF FERMENTING TAN-BARK, 



The experiment showed that tlie bacteria can actively decompose some con- 

 stituent of alley-bark with evolution of COi' and tliat it is practically impossible 

 to destroy the resistant cells (sjjores) by dry heat ranging from ISU" to 205°. 



ZOO 



100 



-L. 



• S OAVS 



Text-fig. 3. The Fermentation of Alley-bark. Daily yields of Carbon dioxide. 

 Unbroken line = test, broken line = control. 



Some stack-bark was dried at 130° and portions weighing 30 grams were 

 put into two Ihusks. Fifty e.c. of water were added to the test and 50 e.c. of 

 1 % mercuric chloride in 1 % sodium chloride to the control. Both were steamed 

 for an hour on three successive days and were then connected up in the ther- 

 mostat at 60°. No attempt was made to sterilise the bark with dry heat, and it 

 was not seeded, as it was considered that the spores would be alive. Later films 

 and growths showed this to be the case. The following shows the amount of 

 carbon dioxide given off daily : — - 





