88 BOTANICAL GAZETTE [JANUARY 
- Conclusions very different from the foregoing regarding the special réle of 
iron in spore-formation are reached by JAVILLIER and SAUTON’ in the paper 
mentioned above. According to this paper iron does not possess a special réle 
in the formation of spores, but in the absence of iron, spore-formation is inhibited 
by the zinc in RAULIN’s solution. If both zinc and iron are excluded, spores 
are readily formed, just as they are when both of these elements are present. 
If zinc alone is present, spore-formation is inhibited. 
The authors suppose that the zinc, which was observed by RAULIN to have 
a favorable effect in the culture solution proposed by him, exerts toxic effects 
when the mycelium is poorly nourished through the lack of iron or from some 
other cause. In the ash of mycelia grown on solutions without iron, no iron 
was found, although the reactions employed were capable of indicating the 
presence of 1/1000 of a milligram of the element; hence the authors conclude 
that if iron is at all essential for spore-formation, the quantity required is so 
small that it cannot be detected in the ash of the mycelium. It is also stated 
that the substance giving the red color with ferric salts and supposed by 
RAULIN to be sulphocyanic acid is not formed when both iron and zinc are 
absent. 
A search for an dsptanation of the favorable effect, noted by Ravin and 
others, of zinc on the growth of Aspergillus has led JAVILLIER® to investigate 
the action of that metal on the secretions of invertase by Aspergillus niger. 
The results are suggestive as showing the influence of certain substances on the 
diffusion of other substances through the protoplasmic membrane. He finds 
that in cultures free from zinc the liquid does not invert sugar, while culture 
solutions containing zinc invert sugar readily after Aspergillus niger has been 
grown on them. This difference, however, does not indicate that no invertase 
is formed in the absence of zinc, for sugar was consumed in both cultures. In 
cultures free from zinc the enzyme does not diffuse into the liquid. 
Several notes have been published by BERTRAND and by BERTRAND and 
JAVILLIER on the influence of manganese on Aspergillus niger and on the rela- 
tions of this element to zinc and iron when present in the culture medium. 
Manganese? i in dilute solutions is found to have a favorable action on the 
of this mold. In solutions containing manganese in concentrations 
ranging from 1 part in 1,000,000 to 1 part in roo, there was a gradual increase 
7 JAVILL t Sauron, B., Le fer est-il indispensable a la formation des 
conidies de Fp) a — Comp Rend. 153:1177-1180. 1911; also Compt- 
Rend. Soc. Biol. 71:589, 590. 
‘8 JAVILLIER, M., aa fi la suppression du zinc du milieu de culture de 
Son niger sur la sécrétion de sucrase par cette Mucédinée. Compt. Rend. 
ach —386. 1912. 
AND, G., et JAvILLiER, M., Influence du manganése sur le développement 
de ‘SPoiemsieang niger. Compt. ood, 152:225-228, 1911; also Bull. Sci. Pharma- 
cologique 18:65-73. 1911; also Bull. Soc. Chim. France. pp. 212-220. 1912+ 
