390 BOTANICAL GAZETTE [DECEMBER 
matocystis. Penicillium spores failed again to show their usu- 
7. 
256 
the usually sensitive CEdocephalum actually germinated 95 per 
cent. and matured a few fruits. 
Molisch (’94) was one of the first to record the toxic prop- 
ally high resistance, proving fatal, a concentration in which 
erties of cadmium to plants. He found = fatal to Aspergillus 
when experimenting with various metals in an endeavor to find 
a substitute for calcium in nutrient media. vi proved fatal 
to the form of Aspergillus used by the writer. 
At its average inhibiting concentration cadmium nitrate 
would be about go per cent. ionized (Grotrian, ’83). 
OXIDIZING AGENTS. - 
Potassium dichromate, K,Cr,O,; 0.094, 0.3, 1.25. 
Potassium chromate, K,CrO,; 0.156, 0.4, 2.25. 
These salts at the dilutions at which they are effective are 
doubtless practically entirely ionized (Ostwald, 88). 
As poisons for the molds they rank, as already mentioned, 
with formaldehyde, silver, and mercury. The anion of the 
dichromate, Cr,O, has a toxic value of about 770 H; that of the 
chromate 575 EH. This may indicate some relation between 
their oxidizing powers and their toxicity. 
The effects of these salts in concentrations permitting 
development of the fungi were very similar, and resembled that 
of H,O,. Retardation of germination in the cultures approach- 
ing the inhibiting point was noticed in all forms with both 
agents, but it was not nearly so well marked as it is in wanes 
Another feature was the fact that every culture that germinate 
any spores developed some conidia within forty-eight hours. 
Toward the higher plants these anions seem to be relatively 
” _ solution of HgrOw 
the same concentration as permitted growth with HCI ( 
93), howevel, 
berg and True, ’96). Toward the alge (Loew, 
much less toxic. Lupinus survives in a 
