[Vor. 8 
256 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
though showing a slightly greater growth, required a third longer 
time to attain this. As in the former experiment, Botrytis de- 
composed a greater quantity of thiosulphate per unit weight than 
Ratio 
7 
Q 
50 N 
vv 
2^ 1 277 
e 
* I p up 
> mmi eu 
10 ts uL. n c a 
4 8 12 16 20 
Days 
thiosulphate decomposed 
growth 
Fig. 5. Penicillium cyclopium, ratio 
the other organisms and produced a greater darkening of the lead- 
paper, indicating a greater production of H,S. Aspergillus, 
though producing an acidity of the solution amounting to Py 
1.7 and finally decomposing all the thiosulphate, failed to produce 
any H,S. This fact is not in agreement with the idea of some 
earlier workers that the acidity produced in the solution might 
be responsible for the separation of free sulphur and the pro- 
duction of H,S. The control flask produced a trace of H,S after 
the fifteenth day but no sulphates were present. The results 
are shown more clearly in figs. 7, 8, and 9. 
Experiment 18.—The chief results as presented in table x1 
are shown graphically in figs. 10, 11, and 12. Aspergillus and 
Botrytis made further increases in growth over the two previous 
