PV R. (iREIG-SlIITH. 59 



pliases known as Al, A2 and A2a. From the plates they were seeded into 

 nutrient broth and transfers were made daily. In tliis medium they doubtless 

 altered in the one direction or the other, but the change was very much slower 

 tlian when a sugar or glycerine was present. The first test with the dextrose 

 medium was made one day after isolation from the plate, and during the growth 

 the medium became ropy and then, after an inter\al, the ropiness disappeared 

 and the liquid became limpid. 



Al became lini|)icl mi the 3rd day. 

 A2 15th day. 



A2a 2()th day. 



The second test was made six days after the isolation of the phase. 

 Al became limpid on the 3rd day. 

 A2 20th day. 



A2a was still ropy on the 26th day. 

 The tliii'd test was made thirteen days after the isolation. 

 Al Ijecame limjiid on the 6th day. 

 A2 was limpid on the 22nd day. 

 A2a was still ropy on the 22nd day. 

 Al -\- A2 was limpid on the 8th day. 

 Al -)- A2a was limpid on the 8th day. 

 In this test the purity of the phases was examined in a few eases. On the 

 12th day, Al contained a few pure typical colonies, and on the 19th day no bac- 

 teria were found in a large loop of the culture. The digestion of the slime is 

 apparently a prelude to the disintegration or death of the bacteria. On the 12th 

 day both A2 and A2a contained bacteria which grew as colonies ■^ith the tint of 

 Al but much more granular; the granular lumps radiated to the margin and 

 became larger as they appi'oached the edge. This was the transition stage be- 

 tween phase Al and A2. On the same day, large loops taken from the mixed 

 growths of Al with A2 and A2a were found to l)e sterile. Phase A2 consisted 

 of Al with a few of A2. 



Other instances of the solution of tlie ropy material will bo seen in the ex- 

 periments dealing with the saline and carbonaceous nutrients. 



The phase A2a gives a more ropy colony on nutrient agar than A2 which 

 is somewhat gelatinous and is not so elastic when touched with the needle. It is, 

 however, difficult to discriminate between the two as, when free to grow, the 

 phase A2 often preponderates. That is to say, a plate when smeared with a 

 reputed culture of either A2 or A2a may show a preponderance of A2a in the 

 comparatively thickly sown parts and A2 in the areas with few colonies. At 

 times, the two phases seemed to be I'emarkably consistent in remaining true to 

 phase. In the majority of the experiments, A2a, has been classified under the 

 phaSe A2 foi< the sake of simplicity but where both A2 and A2a have been 

 simultaneously tested, the original designations have been retained to indicate a 

 duplicate test. 



The earlier observations led to the belief that the disappearance might result 

 from the formation of acid from the sugar but this was negatived by an experi- 

 ment made with tlie idea of determinhig the nature of the acids formed in the 

 presence of sugar. The medium contained dextrose, meat-extract, potassium 

 chloride and chalk; it was seeded w^th a mixture of Al and A2 then known as 

 Bact. A. The liquid never became acid and the particles of chalk were freely 

 suspended when the fla.sk was rotated. It was first incubated at 37°, at which 



