[Vol. 10 



336 



ANNALS OF THE MISSOURI BOTANICAL GARDEN 



weight and the point of disappearance of the sugar are synchro- 

 nous. The organic acids produced in the decomposition of the 

 glucose are probably responsible for the rapid elevation of H-ion 

 concentration. The carbohydrate having been entirely trans- 

 formed, the organic acids are rapidly built up into the substance 

 of the fungus and consequently there is a rapid decrease in [h], 



as indicated by the rapidly ascending curve for the [h] exponent, 

 Ph. This would explain the growth lag evidenced by the Sphae- 

 ropsis and Diplodia. This would probably have been found to 

 be the case also with the faster-growing Aspergillus, had. deter- 

 minations been made at intervals of 5 or 6 hours rather than days. 



TABLE IV 



CHANGES IN H-ION CONCENTRATION. DEXTROSE. TOTAL N. AND 



NITRITE N OF THE MEDIA. AND IN DRY WEIGHT OF 



FUNGOUS MAT 



ASPERGILLUS NIGER— FIRST SERIES 



All weights expressed in mgm. per 50 ml. of media 





Days 



Num- 





Dry 



Dry 



Dry 



Average 









Medium 



incu- 



ber 



P H 



wt. 



wt. 



wt. 



dry wt. 



Total 



NO,. 



Dex- 



^m »^» ^m^ %v ™ ^^m^^^m^B 



ba- 



of 



H 



Mat 



Mat 



Mat 1 



mats 



N 



N 



trose 





tion 



cultures 



5.5 



No. 1 



No. 2 



No. 3 



«*A V* VU 



228.4 















5 











2477 



Peptone 



3 



5 



3.9 



1837 



1810 



1713 



1787 



120 



.0012 



Trace 



plus 



5 



5 



5.4 



1321 



1290 



1336 



1316 



125.2 



.0010 







dextrose 



7 



6 



5.9 



1172 



1192 



1030 



1132 



149.5 











12 



5 



6.5 



1116 



1078 



1129 



1108 



154.7 



.0125 





No. 1 



20 



5 



0.4 



1116 



1120 



1144 



1127 



139.1 



.0073 







30 



6 



(5.4 

 5.7 



1069 



1070 



1045 



1061 



146.1 



.0025 

 





Peptone 







5 









214.5 







minus 



3 



5 



4.8 



222 



271 



232 



242 



189.2 



.0005 





dextrose 



5 



5 



5.6 



338 



263 



312 



304 



208.6 



.0007 







7 



5 



5.9 



294 



258 



258 



273 



208.6 



.0087 





No. 2 



12 



5 



6.3 



249 



237 



238 



241 



187.8 



.0062 







20 



5 



6.3 



250 



252 



227 



243 



196.5 











30 



5 



6.4 

 4.0 



224 



255 



177 



219 



201.7 

 284.0 



.0020 

 











5 











2477 





3 



5 



2.1 



1009 



981 



923 



971 



246.9 



.0005 



365 



(NH^O. 



5 



5 



2.0 



1060 



982 



1149 



1063 



236.4 



.0002 









7 



5 



2.2 



907 



830 



937 



891 



239.9 



.0001 





No. 3 



12 



5 



2.2 



703 



682 



740 



708 



246.9 











20 



5 



2.3 



856 



634 



682 



724 



245.1 











30 



5 



2.3 



644 | 



677 



742 



688 



255.6 









