08 



KOPIXESS IN WATTLE BARK IXFUSIONS, 



in the sugar content might enahle the organism to withstand a higher amoimt of 

 tannic acid. To test the matter portions of fluid containing asparagin 0.5 %, 

 and sodium succinate 0.2 %, were given increasing amounts of dextrose and of 

 tannic acid. The portions were seeded with a drop of a bouillon culture of A2 

 which at the time of inoculation contained A2, 85 %, and Al, 15 %, as shown 

 by plate culture. 



TiiVile X. — Increasing Dextrose and Tannic Acid. 



The portions with 1.5 % of tannic acid were examined on the 8th day. Tliat 

 with 2 % of dextrose contained Al with 5 % of A2, with 4 % of dextrose had A I 

 with 20 % of A2, and 6 % of dextrose had Al with 25 % of A2. 



To judge by the pronouncedly ropy tests, an increase in the sugar does appear 

 to mask, to some extent, the action of the acid, for on the 3rd and 7th days tlie 

 "-(-" indications rise with the amount of acid, but so far as slight ropiness is 

 concerned, thei-e is little difference between the 4 % and the 6 %. The increased 

 sugar also prevents, or rather hinders, the convei-sion of the phase A2 to Al, and 

 thus masks the action of the acid by enabling more ropy substance to be formed 

 Ijy the cohesive phase. 



Sources of Nitrogen. 



An early attempt to determine the most favorable source of nitrogen was 

 made witli solutions of dextrose and mixed salts containing amounts of nitrogen 

 approximately equivalent to 0.2% of asparagin. On the sixth day a mixture of 

 phases Al and A2 had produced I'opiness to a greater or loss degree with as- 

 paragin, meat-extract, peptone, and ammonium sulphate, but potassium nitrate 

 gave little growth and no ropLness. A second test using one-sixth the f|uantili.« 

 of nitrogen and replacing the dextrose by glycerin showed that ropiness had de- 

 veloped by the fiftli day in the presence of all the above sources of nitrogen, and 

 also of potassium ferrieyanide. Thus in the presence of glycerin and mixed salt'< 

 any of these sources of nitrogen will serve. 



At a later date, a more comprehensive experiment was made with jihiuses Al, 

 A2 and B2, using 2 % of dextrose or glycerin, 0.3% of potassium cifrnte and 

 0.25 % of the various nitrogenous substances. 



