Nov. 15, 1924 
485 
A Back rial Leaf spot of Martynia 
INOCULATIONS ON OTHEll PLANTS 
Injured and uninjured leaves of young 
beet plants were sprayed at two different 
times with water suspensions of the 
organism causing leafspot of Martynia. 
No lesions were produced. 
Three attempts to produce infection 
on young cucumber plants in the 
f ;reenhouse gave negative results, 
n one experiment Martynia leaves 
were sprayed at the same time as 
the cucumber plants and kept under the 
same conditions. Typical lesions de¬ 
veloped in abundance on the Martynia 
leaves. 
Leaves of the trumpet creeper, Tecoma 
radicans (L.) Juss., were also inoculated 
by rubbing with a water suspension of 
the organism. No infection resulted. 
THE CAUSAL ORGANISM 
MORPHOLOGY 
The organism is a short rod ,vitb 
rounded ends, occurring singly or in 
pairs. Chains occur on 8-day beef pep¬ 
tone agar (PI. 3, F). Measurements 
of organisms grown 24 hours on beef 
peptone agar and stained with gentian 
violet vary in length from 2.2 m to 1.3m 
in length and from 0.7m to 0.5m in width, 
with averages of 1.68m by. 59m. 
Capsules are present on beef peptone 
agar. (Plate 3, G). Sporangia and 
endospores are not formed. The organ¬ 
ism is motile, having one to several 
bipolar flagella (PI. 3, E). 
The organism is Gram-negative. 2 
Smears from a 2-day beef peptone 
agar culture stained for 5 minutes in 
steaming carbol fuchsin and dipped for 
a few seconds in 20 per cent aqueous 
solution of H 2 S0 4 were not acid-fast. 
CULTURAL CHARACTERISTICS 
Cultures were grown at room tem¬ 
perature unless otherwise noted. 
Bee# peptone agar slants.— 
Growth is moderate, filiform, raised, 
glistening, somewhat contoured. There 
is a slight odor of decay, consistency is 
butyrous with traces of viscidity. The 
growth is white but may have a slightly 
opalescent tinge, and the agar turns 
slightly greenish brown. Numbers of 
small crystals form over and through 
the agar. 
Potato dextrose agar slants.— 
Growth is abundant, spreading, glisten¬ 
ing, somewhat translucent, white by 
reflected light, but deep cream by 
transmitted light. Consistency is bu¬ 
tyrous and there is no odor. 
Gelatin stab. —Held in the Alt- 
mann at about 20° C., growth is best 
at the top and extends only a few 
millimeters down along the line of 
puncture. Liquefaction is stratiform, 
beginning in 48 hours and completed 
in about 2 months. The liquefied 
gelatin becomes slightly fluorescent. 
Nutrient broth. —A thin pellicle is 
formed with small crystals through it. 
When slightly jarred, the pellicle 
hangs down in long loops and strands 
from these crystals, which tend to stay 
on the surface. Clouding is moderate, 
being slightly heavier under the pelli¬ 
cle, and when cultures are undisturbed 
they often show definite bands of 
clouding. As cultures grow older the 
medium assumes a greenish tinge. 
Sediment is moderate in amount and 
granular. 
Nutrient broth plus NaCl. —In 
beef extract broth with a P H 6.9 cloud¬ 
ing appeared in 2 per cent and 3 per 
cent NaCl in 48 hours; in 4 per cent 
after 4 days; and 5 per cent after 12 
days. There was no clouding in 6 per 
cent or 7 per cent NaCl, but in both 
there was some bottom growth. Tests 
made in beef infusion broth with the 
same P H gave the same results. Tests 
made in both infusion and extract 
broth with a P H 8.2 gave clouding in 
2 per cent and in one case in 3 per cent 
NaCl. A few chains occurred in 1 
per cent NaCl and there were many 
long chains in 4 per cent and 6 per cent. 
Cohn's solution. —Clouding is mod¬ 
erate and a thin pellicle forms from 
which hang large triangular crystals 2 
to 4 mm. in length in 3 days. These 
crystals tend to pull down the pellicles, 
but crystals still hanging from the sur¬ 
face after 3 weeks are one-half to three- 
quarters of an inch in length. There 
was no green fluorescence. 
2 Methods I and It as recommended in “Manual of Methods for Pure Culture Study of Bacteria S. 
A. B.,” were followed. 
EXPLANATORY LEGEND FOR PLATE 1 
A. —Natural infections on leaf of Martynia louisiana (= M. proboscidea ) collected at Garden City, Kans., 
Aug. 31, 1922. Photographed by transmitted light Sept. 5, 1922. X 1. Photographic work by James F 
Brewer. 
B. —Leaf of Martynia louisiana (= M. proboscidea ) showing artificial infections. Sprayed Aug. 22, 1923, 
with water suspension of Culture I in field. Photographed by rellected light Sept. 7, 1923. X 1. 
