CHEMICAL STIMULATION OF GROWTH OF ASPERGILLUS NIGER 347 
21. The effect of an increase or of a decrease in acidity of the culture medium. 
Strain W, 7 
Control 
NH4OH (Sp. Gr. 
0.90) 
KOH (5:6) 
*o.907 
0.02 cc./flask 
0.214 g. 
0.02 cc./flask 
0.I4I g. 
0.211 
0.04 
0.135 
0.04 
0.140 
0.196 
0.06 
0.158 
0.06 
0.185 
0.112 
0.08 
0.224 
0.08 
0.182 
0.112 
O.IO 
0.I3I 
O.IO 
0.183 
0.126 
HNO3 (Sp. Gr. 
1.42) 
HCl (Sp. Gr. I,] 
8) 
H2SO4 (Sp. Gr. 1 
.84) 
0.02 cc./flask 
0.130 g. 
0.02 cc./flask 
O.II2 g. 
0.02 cc./flask 
0.244 g. 
0.04 
0.233 
0.04 
0.II5 
0.04 
0.336 
0.06 
0.282 
0.06 
0.2II 
0.06 
0.239 
0.08 
0.289 
0.08 
0.329 
0.08 
O.IIO 
O.IO 
0.266 
O.IO 
0.274 
O.IO 
0.028 
* Accidentally used a Jena flask. 
I accidentally added the NH4OH, KOH, HNO3, etc., to the flasks before sterilization. 
Spore formation in all except the cultures to which acids were added was excellent. Good 
sporulation in all cultures with HNO3 and HCl. H2SO4 : 0.02 cc, excellent spore forma- 
tion, translucent hyphae; 0.04 cc, opaque hyphae; 0.06 cc, dense white hyphae, slight 
retardation of spore formation; 0.08 cc, thin, dense white membrane, few spores; o.io cc, 
submerged hyphae, no membrane. 
22. The effect of an increase in acidity of the culture medium. 
Strain W, 7 
Control 
Tartaric Acid 
Acetic Acid (ggi) 
0.078 g. 
0.082 
0.091 
0.087 
0.090 
0.5 cc./flask 
1.0 
1-5 
2.0 
0.184 g- 
0.305 
0.352 
0.387 
0.407 
O.I cc./flask 0.236 g. 
0.2-0.5 No growth 
i 
0.086 
! 
A time retardation of spore formation was evident in cultures containing 2.0 and 2.5 g. 
tartaric acid to the 50 cc. of nutrient solution. 
23. The effect of an increase or of a decrease in acidity of the culture medium. 
Strain W, 8 
Control 
NH4OH (Sp. Gr. 0.90) 
KOH (5:6) 
O.I3I g- 
0.135 
0.II2 
O.III 
0.136 
0.05 cc./flask 
0.1 
0.2 
0.3 
0.4 
0.166 g. 
0.055 
0.039 
No growth 
0.02 cc./flask 
0.05 
0.1 
0.2 
0.3 
0.107 g. 
0.081 
0.057 
0.075 
No growth 
0.125 1 
Ba(0H)2 (0.084 N) 
HNO3 (Sp. Gr. 1.42) 
O.I cc./flask 
0.3 
0.5 
1.0 
1-5 
0.117 g. 
O.IOI 
0.157 
0.180 
0.163 
0.02 cc./flask 
0.05 
0.08 
0.1 
0.2 
0.070 g. 
0.125 
0.169 
0.336 
No growth 
