348 
ROBERT AARON STEINBERG 
H3PO4 (Kahlb. Kryst.) 
O.I cc. /flask 0.303 g. 
0.2 
0.286 
0.3 
*o.905 
0.4 
0.266 
0.5 
0.180 
H2S04 
(Sp. Gr. 1.84) 
HCl (Sp. Gr. 
1. 18) 
0.02 CC. /flask 
0.188 g. 
0.05 CC. /flask 
0.107 g. 
0.04 
0.244 
0.1 
0.261 
0.06 
0.260 
0.2 
0.227 
0.08 
0.167 
0.3 
0.039 
O.IO 
0.034 
0.4 
No growth 
HC2H3O2 (99?«) 
0.02 CC. /flask 0.225 g. 
0.05 
0.253 
0.08 
0.279 
0.1 
0.280 
0.2 
No growth 
H2C204 
+ 0.1 Mg. Zn/L 
O.I g./flask 
0.202 g. 
0.08 CC. H2S04/flask 
0.572 g. 
0.2 
0.289 
0.3 
0.337 
0.02 CC. NH40H/flask 
0.203 
0.4 
0.233 
0.5 
0.043 
The reactions of the freshly prepared cultures were all acid to litmus except: KOH — 0.2 
and 0.3 cc; and NH4OH — 0.2, 0.3, and 0.4 cc. 
On the second day sporulation was complete in the controls: NH4OH — 0.05 and o.i 
cc; Ba(0H)2 — all; HC2H3O2 — 0.02, 0.05, and 0.08 cc On the seventh day sporulation 
was completed in the controls, and in the cultures to which KOH, NH4OH, Ba(0H)2, 
and HC2H3O2 had been added. The lowest concentrations of acid causing partial suppres- 
sion of spore formation were: HNO3 — 0.1 cc; H3PO4 — 0.4CC.; H2SO4 — ^o.o6cc.; HCl — 0.2 
cc. and H2C2O4 — 0.2 g. 
As respects the cultures to which zinc had been added, those containing H2SO4 was 
practically sterile, those containing NH4OH black with spores. 
* Accidental zinc culture. 
24. The effect of an increase or of a decrease in acidity of the culture medium. 
Strain W, 1 1 
Control 
0.1 Mg. Zn/L 
0.2 Cc. NH4OH /Flask 
0.2 Cc. H3P04/Flask 
0.066 g. 
0.869 g. 
0.016 g. 
0.229 g. 
0.035 
0.853 
1 
0.233 
0.086 
0.862 
0.026 
0.226 
0.084 
0.782 
0.024 
0.262 
t 0.677 
0.91 1 
* 0.902 
0.068 
0.855 
0.022 
0.238 
Acidities on harvest corresponded to pn = 3-4 (control, NH4OH); 2-3 (H3PO4), 
and 1-2 (0.1 mg. Zn/L). 
* Accidental zinc culture. 
t Accidental stimulation resulting from addition of methyl violet 6 B extra Griibler, 
which may or may not be due to impurities. 
t Not inoculated: pn on harvest < 6.8; of the inoculated flasks pn = 3~4- 
