556 The Philippwe Journal of Science isis 



made on one cover, but it is usually best to employ separate 

 covers for each. The nature of the growth in each drop may 

 be examined microscopically before transfer, and a record kept 

 by lettering and numbering the rows. 



ADDENDUM 



A special experiment was arranged to test the consta.ncy of 

 several different races of dysentery bacilli. All were isolated 

 from stools of cases of dysentery occurring in Manila during 

 the summer of 1912. There were 8 strains, 5 of them of the 

 Shiga-Kruse type, 2 of the Flexner, and 1 with the characteris- 

 tics of the Flexner but with a tendency to ferment lactose. Soon 

 after isolation from the stools, a one-cell pure culture was made 

 of each. This pure culture gave the same reactions as the stock 

 on lactose-, glucose-, maltose-, and mannite-litmus agars. The 

 cultures were now placed at room temperature on ordinary agar 

 and transferred at about monthly intervals for about eleven 

 months. At the end of this period fresh agar cultures were 

 transferred to plain broth, glucose-broth fermentation tubes, 

 litmus-lactose broth fermentation tubes, and to the following 

 litmus agars: lactose, glucose, mannite, saccharose, maltose, levu- 

 lose, dextrin, salacin, glycerine, erythrite, inulin, raffinose, 

 galactose, amygdalin, and dulcite. The results of these cultures 

 were the same as those observed eleven months before, and the 

 one-cell pure culture gave the same reactions as the stock in 

 ever>^ case. Apparently both the one-cell culture and the stock 

 culture isolated from a colony had kept their characteristics 

 constant during this period. 



Well-marked secondary colonies were formed by 4 different 

 strains, all of the Shiga-Kruse type. Two of these strains 

 formed the secondary colonies only on saccharose-litmus agar, 

 1 on both saccharose and maltose, and 1 on saccharose and 

 lactose. All secondary colonies were transferred to new tubes 

 of litmus agar containing the appropriate sugar. All transfers 

 from secondary colonies on saccharose gave acid-forming cul- 

 tures, while those from the maltose and lactose gave alkali- 

 forming cultures. 



A test was made of the composition of the two strains which 

 had produced secondary colonies only on saccharose. From a 

 series kept on ordinary agar and never passed through sac- 

 charose, 45 single cells were isolated from one strain and 49 

 from the other, and the cultures from these 94 single cells were 

 tested on saccharose-litmus agar. Only one culture proved to 



