1921] 
ARMSTRONG—SULPHUR NUTRITION IN THE FUNGI, THIOSULPHATE 265 
solution to 10 ec. of the culture solution which was then warmed. 
If no precipitate appeared, a few drops of HCl were added to 
another 10-cc. portion of the culture, this brought to a boil, and 
Fehling's solution added as before. The latter step was not 
Dry wt Cc. 
cams. Pa lodine 
100 2 P 2 
7 
"d 
E. 
80 z 4 6 
L 
7 
M 
60 /[— 74 m 10 
rj 
— 
20 L : 18 
/ vts 
/ 
Pd 
4 
[*] 7 22 
0 4 8 12 16 20 
Days 
Fig. 11. Penicillium cyclopium on solution of initial Pa 5.9 con- 
taining thiosulphate. 
necessary in any case where sugar was present, for there appeared 
to be some inversion even in the control flasks. A comparison 
of the changes in reaction caused by the different fungi can be 
seen from table xtv and figs. 16, 17, and 18. The peak of growth 
for Aspergillus is reached by the seventh day, with a total dis- 
appearance of the sugar and only a slight decrease in the acidity 
from Py 1.5 to 1.9. The peak of growth was not reached by 
Botrytis even at the eighteenth day, neither had the sugar been 
