Allg. 15 1924 
Bacterium Marginatum on Gladioli 
173 
equal to that in Uschinsky’s solution 
or beef bouillon. Numerous crystals 
form in the pellicle, in fact the weight 
of the crystals causes the pellicle to 
fall. Fallen pellicles and crystals form 
the sediment. The pellicles and Pedi¬ 
ment are slimy to viscid. In most tests 
the sediment becomes yellowish. One 
set of cultures developed a pale but 
clear orange-yellow color in the pelli¬ 
cles, crystals, and sediment. 
Nitrate bouillon. —There is good 
growth in this medium, but nitrates 
are not reduced. 
Indol. —In Dunham’s solution, in 
1 per cent and in 2 per cent peptone 
water a slight amount of indol was 
produced. 
Ammonia. —Tests were positive for 
ammonia in cultures grown in 2 per 
cent peptone water, milk, beef 
bouillon, and other media. 
Hydrogen sulphide.— Produced 
only in very slight amounts. 
Aerobism. —Shake cultures of agar 
show growth only at the surface. No 
growth occurs at the lower end of stab 
cultures in agar or gelatin. Plate and 
tube cultures made no growth in an 
atmosphere deprived of oxygen. 
Optimum reaction for growth in 
bouillon. —The organism grows best 
in peptone-beef bouillon titrating +8 
to +12. Sodium hydrate was used as 
the alkali and hydrochloric as the 
acid. It grew well in various acid 
reactions up to +40. Growth oc¬ 
curred in +43 in 48 hours and in +45 
within 6 days in one case and within 
10 days in another. No growth 
developed in medium more acid than 
+ 45. The range of growth was more 
limited on the alkaline side. The 
amount of growth gradually lessened 
from +10. In —4 to —5 clouding 
was evident within 24 hours. In —6, 
— 7, and —8 clouding was not observed 
until the second day. In —9, no 
growth. In several cases clouding was 
observed on the fifth day in —9, but 
here it was assumed that the medium 
had become more acid in the interval. 
In addition to the titration by Fuller’s 
method with phenolphthalein used as 
the indicator, colorimetric determina¬ 
tions (Clark and Lubs’ series) were us¬ 
ually made and in some cases determina¬ 
tions by the electrometric method 
(Table I). 
In bouillon made with beef extract 
and titrating +30 the organism made 
no growth. With this mediun titrating 
from +3 to +25 the organism grew 
within 24 hours. 
Toleration of organic acids.— 
Peptone-beef bouillon +12 containing 
malic, citric, oxalic, and tartaric acids 
in amounts to make 0.1, 0.2, and 0.3 
per cents were inoculated from 3-day- 
old beef bouillon cultures. The organ¬ 
ism grew well in the 0.1 and 0.2 per cent 
of malic, citric, and tartaric acids. In 
0.1 per cent oxalic acid growth occurred 
only as a surface pellicle. No growth 
occurred in 0.2 per cent oxalic, or in any 
of the 0.3 per cents acids. 
Table I.— Reactions of Bacterium marginatum to acid and to alkali in beef bouillon 
(+ indicates growth; —, no growth ) 
Fuller 
Colorimetric 
Electrometric 
24 hours 
48 hours 
5 days 
Ph 
Ph 
-9 
9.2 
8. 96 
— 
— 
— 
-9 
9.1 
8.63 
— 
— 
+ 
-8 
8.8 
— 
+ 
+ very faint 
-7 
8.8 
8.5 
— 
+ 
+ 
-6.5 
9.0 
8.59 
— 
+ 
+ faint 
-5 
8.7 
+ very faint_ 
+ faint 
-4 
8.6 
+ faint_ 
+ 
—2 
8.3 
+ faint . 
+ 
0 
8.2 
+ faint_ 
-|—|- 
+5 
7.9 
7.7 
+ 
++ 
+++ abundant 
+8 
7.2 
++ moderate... 
++ 
+++ abundant 
+10 
7.1 
++ moderate. .. 
++ 
+++ abundant 
+12 
7.0 
6.89 
++ moderate. .. 
++ 
+++ abundant 
+15 
6. 7 
+ 
++ 
+20 
6.6 
6.55 
+ 
++ 
+25 
6.4 
6. 26 
+ faint_ 
++ 
+33 
5. 3 
± faint.... 
++ 
+35 
5.2 
4. 87 
+ faint .. 
++ 
+39 
4.8 
4.6 
+ very faint. 
++ 
+39 
+ 
++ 
+41 
_ 
+ 
++ 
+43 
_ 
+ 
++ 
+44(?) 
4.6 
4. 62 
— 
+ 
+ 
+45(?) 
4.6 
4. 58 
— 
— 
— 
—46(?) 
4.6 
4. 61 
" 
