540 The Philippine Journal of Science ms 



bacilli. Twenty-one single cells were isolated and allowed to 

 develop overnight in hanging drops, and were then transferred 

 to ordinary agar. After twenty-four hours' growth, they were 

 transferred to maltose-litmus agar and incubated. Of the 21, 

 16 gave cultures like the original stock ; that is, with blue surface 

 growth and, at most, only slight acid formation at the bottom; 

 while 5 gave within twenty-four hours the practically complete 

 cherry-red color to the agar, such as is found in any maltose- 

 fermenting organism. After twenty-four days at room temper- 

 ature, 2 of the 5 red cultures remained clear red, 2 showed the 

 lower two-thirds of the tube red with the upper part becoming 

 blue, and the fifth had become almost wholly blue. The 16 origi- 

 nally blue cultures showed a deep blue, deeper than the uninocu- 

 lated controls. Transfers from the originally red cultures, that 

 had now become blue, to fresh maltose agar gave distinct red 

 cultures like the original ; while transfers from the blue gave blue 

 cultures. So, in spite of the later change to blue through long 

 exposure to the air, the red cultures possessed a distinct fermen- 

 tative difference from the blue in that they showed complete red 

 in forty-eight hours; and, although becoming blue later, gave a 

 distinct red color on transfer to a new maltose-litmus medium. 

 The change of the red coloration to blue on long exposure 

 was not constant. In some whole series the agar remained 

 red for weeks. Some slight variations in the composition of 

 the medium may account for the differences. It was found 

 that cultures remaining acid were more likely to die out. 



A further characteristic of the original blue variety is the 

 property of forming on maltose agar secondary colonies capable 

 of fermenting maltose. These colonies are somewhat elevated, 

 denser than the surrounding growth, and usually well defined 

 in the substratum. They often appear within forty-eight hours, 

 sometimes increasing in number during subsequent days, and, 

 in this series, varying from 1 to 300 per test tube. They often 

 increase in size, and may become 4 millimeters or more in 

 diameter. At first they show no color, but later change the 

 agar at their base to a dull red, and if numerous may redden 

 the whole tube. If a transfer is made from one of these colonies 

 to a new tube, a permanently acidifying growth is obtained ; 

 while a transfer from the intervening substratum gives a blue 

 culture like the original. 



Many references are found in the literature to secondary 

 colonies of this sort ("papillae," "Knopfe," "Knotchen") pos- 

 sessing new fermentative characteristics. They were described 



