BV R. GEEIG-SMITH. 



63 



The diiplictite tests ut' phase B2 were lairly cuiieonhmt; ditt'erences were ob- 

 tained with levulose and saccharose in conjunction with ammonium sulphate. 

 With asparagin, a slight difference occurred in the case of levulose. 



Phase IVi, in this experiment, was shown to possess considerable activity in 

 producing ropiness in tlie presence of tannic acid as compared with the prelimin- 

 ary tests, liut it is possible that the saline constituents had much to do with the 

 ditt'erences obtained . 



In the experiment the media contained 0.5 of tannic acid and, as ropiness was 

 obtained with this percentage, it was deemed advisable to see to what extent the 

 most active phase could tolerate this acid. A medium containing dextrose 2 %, 

 asparagin or ammonium sulphate 0.25 % and sodium succinate 0.2 % was por- 

 tioned out and seeded with phase A2 taken from a colony two days previously. 

 Then the various quantities of tannic acid were added. 



Table vi. — Dextrose with increasina; Tannic Acid. 



On the 6th day certain of the cultures were smeared on agar. With 0.2 % 

 and 0.6 % of tannic acid, in the presence of asparagin, the colonies were of a 

 novel type. They appeared as round, raised, glistening, buff-coloured colonies 

 with a glutinous consistency. Microscopically they had dark centres from which 

 dark tufted fibres radiated through a yellow matrix to near the margin. In 10 

 % of the colonies this structure blended into that of phase A2, part of the colony 

 showing the fibrous structure at one side and that of A2 at the other. They were 

 clearly a transition phase of A2 more nearly related to A2 than to Al. With 

 1 % and 2 % of tannic acid the colonies consisted entirely of the phase Al . 



By the 12th day, the medium containing asparagin with 0.2 % of acid showed 

 96 % "of Al, 2 % of the fibrous transition form of A2, and 2 % of A2. With 

 larger amounts of acid the cultures contained very few living bacteria but they 

 were of the kinds noted on the 6th day. 



The cultures containing ammonium sulphate w^ere tested on the 12th and 16th 

 days. They contained few bacteria; with 0.2 % of acid, they consisted of the 

 introduced phase A2 an<l. with larger quantities, they were the Al phase. 



