20 STEINBERG: GROWTH OF ASPERGILLUS NIGER 
LITERATURE CITED 
1. Javillier, M. La presence et le rdle du zinc chez les plantes. Thése. 
Paris. 1908. 
2, Ono, N. Uber die Wachsthumsbeschleuniging einiger Algen und 
Pilze durch chemische Reize. . Jour. Coll. Sci. Imp. Univ. Tokyo 
13: 142. 1900. 
3. Raulin, J. Etudes chimiques sur la végétation. Ann. Sci. Nat. 
Bot. V. 13: 93. 1869. 
4. Richards, H. M. Die Beeinflussung des Wachsthums einiger Pilze 
durch chemische Reize. Jahrb. Wiss. Bot. 30: 665. 1897. 
5. Richter, A. Zur Frage der chemischen Reizmittel. Die Rolle des 
Zn und Cu bei der Ernahrung von Aspergillus niger. Centralbl. 
Bakt. II 7: 417. 1Igor. 
Steinberg, R. A. A study of some factors influencing the stimula- 
tive action of zinc sulphate on the growth of Aspergillus niger. 1. 
The effect of the presence of zinc in the cultural flasks. Mem. 
Torrey Club 17: 287. 1918. 
7. Thom, C., & Currie, J. N. The Aspergillus niger group. Jour. 
Agr. Research 7:1. 1916. 
de 
Explanation of plate 1 
All photographs from Exp. XVIII 
First Row. Wstrain. No zinc added to the cultures. 
SECOND ROW, strain. No zinc added to the cultures. 
THIRD ROW. W strain. Cultures contain from left to right 0.01, 0.02, 0.03, 0.04, 
FourTH ROW. W strain. Cultures contain from left to right 0.06, 0.07, 0.08, 0.09, 
0.10 m: 
FIFTH ROW. Y strain. Cultures contain ‘iiss left to right 0.01, 0.02, 0.03, 0.04, 
0.05 m 
SIxTH ROW. Y strain. Cultures pans from left to right 0.06, 0.07, 0.08, 0.00, 
oO. /L. 
SEVENTH ROW. Cultures from left to right: W zinc-free, Y zinc-free, W 0.1 mg. Zn/L, 
