[Vol. 10 



284 



ANNALS OF THE MISSOURI BOTANICAL GARDEN 



desirable to have had more cultures for each determination. 

 Culture 14 gave much better growth in solution 2 than in solution 

 1, as well as a delayed utilization of dextrose in the former. This 

 would indicate that the citric acid was used at the same time as 

 the sugar and that the former had a high mat-building value. 



Days 



o 







lb 



.0 



+ 



x 



u 



A 



X 



51 



Fig. 16. Alternaria sp. in solution 1. 



Unfortunately, contaminations prevented the completion of the 

 curves. For organism 7 additional weights not shown on the 

 curves were obtained as follows: 



Day 





Wgts. in mgms. 





Solution 1 



Solution 2 



43rd 

 47th 

 50th 



341 



376 



502 

 486 



These figures indicate that the maximum had already been 

 reached, though there was still a slight trace of dextrose in solution 

 2 on the forty-seventh day. The maximum in solution 2 on the 

 twenty-ninth day was apparently too great to represent an 

 average culture, the peak of the curve being too sharp at this 

 point. Where growth is as slow as it is with this organism, it 

 is likely that there is reached a condition in which autolysis 

 balances or even exceeds the amount of growth due to the utili- 

 zation of the carbohydrate still remaining in the solution. It 



k 



