Dec. 10, 1913 
Disease of Sugar-Beet and Nasturtium Leaves 
207 
occurring in maple sap. Results of a comparative study of seven repre¬ 
sentative strains of the green fluorescent sap bacteria and six known 
fluorescent species are given, and the group numbers of these organisms 
determined. Since one of these numbers, that of Pseudomonas tenuis 
is identical with the group number of Bacterium aptatum , it was found 
necessary to make cultural comparisons. A culture of Pseudomonas 
tenuis was obtained by Dr. Erwin F. Smith from Mr. C. E. A. Winslow, 
American Museum of Natural History, who stated that he had received it 
from Mr. Edson. 
Table II shows the results of comparative tests made with Pseudo - 
monas tenuis and Bacterium aptatum . 
Table II. —Comparison of the characteristics of Pseudomonas tenuis and Bacterium 
aptatum. 
Media, etc. 
Pseudomonas tenuis. 
Bacterium aptatum. 
1. Bed bouillon. 
2. Bed-agar stroke. 
3. Uschinsky's solution. 
4. Nitrate reduction. 
5. Indol test. 
6. Hydrogen - sulphid 
test. 
7. Gelatin plates. 
Rapid clouding; green fluorescence; 
distinct pellicle. 
Smooth, thin, whitish growth; 
medium greened. 
Strong clouding with fluorescence; 
pellicle formed. 
None. 
No indol in 10-day cultures, but 
present in 16-day cultures. 
Hydrogen sulphid produced.. 
A trace of liqudaction in 3 weeks on 
thickly sown plates. 
3 . Gelatin stabs.. 
9. Sterilized milk 
10. Litmus milk. 
No liqudaction in 3 weeks. 
Gradual thickening in 6 weeks with¬ 
out clearing. 
Alkalin reaction; color uniform 
throughout during 7 weeks. 
11. Ammonia test. Ammonia produced.. 
12. Pathogenicity. Nonpathogenic to sugar-beet and nas¬ 
turtium leaves. 
Clouding with green fluorescence; 
distinct pellicle. 
Smooth, thin, whitish growth; 
medium greened. 
Strong clouding with fluorescence; 
pellicle formed. 
None. 
Indol present in 10 to 12 days. 
No hydrogen sulphid. 
Liquefaction begins on second day and 
is complete in 5 days in thickly sown 
plates. 
Liqudaction begins in 2 to 3 days. 
Clearing begins in 2 to 3 days and is 
completed in 2 weeks. 
Alkalin reaction; banded appearance 
resulting in clearing and a uniformly 
blue color in 3 to 4 weeks. 
Ammonia produced. 
Pathogenic to sugar-beet and nastur¬ 
tium leaves. 
From results given in Table II it is evident that Pseudomonas tenuis 
and Bacterium aptatum } although closely related in the green fluorescent 
group of bacteria, do not belong to the same species. Similarity of 
growth occurs and was especially noticed in beef bouillon, on beef agar, 
and in Uschinsky's solution. Pseudomonas tenuis , however, clouds bou¬ 
illon and Uschinsky’s solution more quickly than Bacterium aptatum. 
Both organisms produce indol and ammonia. Neither reduces nitrates. 
Pseudomonas tenuis has a strong putrefactive odor not present in cultures 
of Bacterium aptatum. Pseudomonas tenuis produces hydrogen sulphid, 
while Bacterium aptatum does not. In sterilized-milk cultures, Bacterium 
aptatum gradually separates whey from curd, and in litmus milk this 
process is accompanied by changes of color, giving a distinctly banded 
appearance during the first week’s growth. Neither the separation of 
1 Zimmermann, O. E. R. Die Bakterien unserer Trink- und Nutzwasser . . . Reihe 1, Chemnitz, 1890. 
106 p. Also in 11. Bericht, Naturwissenschaftliche Gesellschaft, Chemnitz, 1887,1889, p. 53-154. 1&90. 
Thumm, Karl. Beitrage zur Biologie der fluoresderenden Bakterien. Arb. Bakt. Inst. Karlsruhe, Bd. 
1, Heft 3; p. 291-377. [1895J 
