64 



liOPIXESS IN WATTLK BARK INFUSIONS 



The teiideney of the tannic; acid is to alter the phase A2 to Al but this pro- 

 bably occurs alter the ropy substance has been formed in the medium. 



The experiment showed that a fairly active culture of the phase A2 could 

 produce ropiness in the presence of <iuantities of tannic acid up to 1 % with 

 ammonium sulphate, and up to 1.5 % with asparagin. 



The sugar test with 0.5 % of tannic acid showed that galactose was a useful 

 sugar for inducing the formation of ropiness, and an experiment was made to 

 see the effect of increasing quantities of tannic acid in the presence of this sugar. 

 The medium contained galactose 2 %, asparagin 0.25 %, sodium succinate 0.1 %, 

 and sodium jiliospliate, anhydrous. 0.2 %. The phases were plated at the start 

 and found to be pure. 



'I'he flasks with 0.5 % and 1 % of tannic acid were examineil sexeral limes by 

 the plate method on nritrient agar with fhc following results: — 



Table viirt. — Change of Phase. 



