386 OLDENBUSCH: STIMULATION OF PLANTS 
After being stoppered, the flasks were left in a dark chamber 
at room temperature and, as a preventive measure, the controls 
were put in a different compartment from those to which carbon 
disulphide had been added. After five days, the flasks were 
removed, pads filtered off on weighed filter paper and dried in 
hot air oven at 70° to dry weight. No attempt was made to 
determine the CO, or acid production, although this would have 
been an interesting point to investigate. 
Although growth was not wholly normal in the controls, 
presumably due to lack of adequate circulation which may have 
caused carbon dioxide to accumulate, nevertheless the gross 
appearance of the stimulated was strikingly different from that of 
control specimens. The solutions containing CS, in the most 
optimum concentrations bore tough pads, thicker and con- 
siderably heavier than normal. All the stimulated pads were 
wrinkled and curled, and slightly yellow on the under surface. 
Practically no spores were produced, although in some cases a 
few yellow sporangia were observed. The control felts on the 
other hand were thin and tender in texture, and more or less 
covered with, black spores. However, if further experiments 
were to be carried out, a more perfect system of maintaining the 
concentration of CS, in the flasks would have to be devised in 
order to obtain absolutely normal controls. 
TABLE IV 
DrY WEIGHT IN MILLIGRAMS OF CULTURES OF STERIGMATOCYSTIS NIGRA, 
GROWN IN NUTRIENT SOLUTION TO WHICH CS, HAD BEEN ADDED 
Exp. Control. M/80,000 M/40,000 M/20,000 M/10,000 M/5,000 
2 
No CS 
A 439 838 800 740 585 270 
B 442 1028 815 748 675 370 
Cc 530 765 1035 495 490 oe 
D 578 788 740 810 540 casa 
Avg 497 855 848 698 573 320 
The results of TaBLE IV are sufficient to indicate that there: 
is a marked stimulation in cultures to which carbon disulphide 
has been added. The region of greatest stimulation is in the 
flasks M/80,000 and M/40,000 CS, solutions, the more dilute 
- concentration being slightly more advantageous than the other. 
