86 BOTANICAL GAZETTE [JANUARY 
the ash of the fungus are increased, but the increase corresponds to the amount 
of calcium absorbed. The increase of the ash corresponds to the amount of 
calcium absorbed calculated as calcium carbonate. It appears from this 
paper that calcium is of no importance for the development of Aspergillus niger, 
but that when present in the culture medium, it is absorbed and increases the 
yield and ash only by the amount absorbed. 
In another paper4 Mlle. Ropert concludes that the calcium absorbed from 
solutions by Aspergillus niger is quantitatively fixed in the form of calcium 
oxalate. This conclusion is based on analyses of mycelia from a large number 
of cultures. Although it was necessary to determine the calcium and the 
oxalic acid in different cultures, the determinations showed that the oxalic acid 
present in the mycelium corresponded to the quantity calculated on the 
assumption that all the calcium fixed was present in the form of a 
oxalate. Owing to the fact that in the cultures without calcium the o 
acid formed diffuses into the medium, mycelia from such cultures pee: 
contain less oxalic acid than those with calcium 
SAUTON,5 studying the effect of iron on spore-formation of Aspergillus niger 
grown on RAULIN’s solution free from iron, finds that in the absence of iron no 
spores are formed by this fungus. This fact, while not mentioned specifically 
RAULIN, seems nevertheless not to have escaped his notice completely, for 
he states that in the absence of iron spores become fewer and fewer in propor- 
tion to the number of crops of fungus grown on the same solution. When iron 
is added to cultures free from iron, the yield increases and spores are produced. 
Cultures with o.1 mg. of iron per roo cc. of liquid and those with 1.0 mg. pert 
100 cc. gave practically the same yield, but spore-formation was almost sup- 
pressed in the 0.1 mg. cultures, while those with 1.0 mg. per roo cc. were 
black with spores. The cultures without iron made feeble growth and pro- 
duced no spores. Since there was no difference in growth but a great difference 
‘in spore-production between cultures containing 0.1 mg. of iron per 100 CC. 
of liquid and those containing 1.0 mg. per roocc., the author concludes that 
iron has a specific influence on spore-formation. The possibility that toxic 
‘substances are produced in the absence of iron had already been suggested by 
Ravtin, who noted that in cultures without iron a substance is formed which 
he regarded as sulphocyanic acid, and FernBacH had shown that in the 
presence of ammonium sulphocyanate Aspergillus niger grows naturally but 
does not form spores. SautTon doubts the formation of sulphocyanic acid, 
since the liquid from cultures containing 0.1 mg. of iron per roo cc. (in which 
spore-formation is almost inhibited) does not give the red color reaction with 
ferric salts. In cultures without iron, however, a faint red color reaction 
4 Ropert, Mive., Mode de ixation du calcium par l’Aspergillus niger. Compt. 
Rend. 154: 1308-1310. 1912. 
sSauton, B., Influence du fer sur la formation des spores de Aspergillus niger. 
Compt. Rend. 151:241-243. I910. 
