APPENDIX I 



353 



and plate cultures were made, using azolitmin isodulcite agar. These 

 individual plates were themselves observed for several days. 



In 48 hours a second plate was made from each flask and so on 

 for 6 days. The following Chart II. illustrates what occurred 

 graphically. 



CHAET II 



In 4 days there was no change in colour in the flask culture, but 

 in 5 days a very slight pink could be noticed, which had not increased 

 in 6 days. It will be seen that no change occurred even after 

 3 days in the 24-hour, 48-hour, or 72-hour plates, and only a slight 

 change in the 4-day plates. However, marked growth and distinct 

 fermentation occurred in the 5-day plates, and in the 6-day plates. 



It would seem that direct ' adaptation to environment ' had 

 occurred. On examining these plates by chance three weeks later 

 it was seen that they were blue again, and apparently the organism 

 had lost its affinity for isodulcite, and was growing again on the agar 

 without producing acid. 



2a 



