Feb. 3, 19*3 
Bacterial Leafspot of Geranium 
365 
zooglea are present. In 2 to 4 days an incomplete pellicle is formed and 
the medium is clear below the pellicle. Cultures are not viscid until 
1 month old or older. When the tube is agitated the pellicle drops to 
the bottom in flocks. No green color is produced in either young or old 
cultures. Some bouillon was made containing Witte's peptone, and the 
organism grown in it was compared with that containing Difco peptone 
to see whether the green color would appear. It did not, nor when ex¬ 
tract of beef was used with the two kinds of peptone instead of the beef 
stock. There was no trace of a green color at any time. (The Lewis 
organism greens the bouillon.) 
Dunham’s solution with methylene blue. —The organism grows 
well in Dunham’s solution colored with methylene blue. The color 
changes to a faint blue in four days. This test was repeated with the 
same result. The color reduced from the bottom of the tube upward. 
In 22 days the methylene blue is reduced to a mere trace. In 1 month 
after inoculating the color begins to return, but is a green instead of 
blue—light hellebore green, according to Ridgway. 9 (The Lewis organ¬ 
ism does not change the blue color; observations were made over a 
period of 4 weeks.) 
Bouillon with sodium chlorid. —Growth takes place in neutral beef 
bouillon to which 2.5 per cent sodium chlorid is added. Tests were 
made with 3.5 and 4 per cent sodium chlorid, but no growth took 
place in either of the latter media. (Like the Lewis organism.) 
Bouillon over chloroform. —No growth occurs in 10 cc. of peptone- 
beef bouillon over 5 cc. of chloroform. Three different tests were made, 
one in which the quantity of chloroform was reduced to 3 cc. No 
growth occurred. The same bouillon inoculated without chloroform 
showed abundant growth in 48 hours. (The Lewis organism grows in 
this medium.) 
Decoction of geranium leaves. —Fifty gm. of fresh geranium 
leaves were boiled in a liter of water, then filtered and autoclaved. It 
tested+ 6, Fuller’s scale; P H 4.1. The organism was slow in appearing 
and grew but feebly in this medium. (Not unlike the Lewis organism.) 
Geranium agar. —Some of the decoction described above was made 
up into agar by adding 2 per cent agar. The medium titrated + 6 Ful¬ 
ler’s scale; P H 4.1. A mere trace of growth occurred in the agar made 
from the decoction. (Not unlike the Lewis organism.) 
Nitrate bouillon. —There is slight growth in 2 days in beef bouillon 
containing 1 per cent potassium nitrate; good growth in four days. A 
partial pellicle is formed rather heavy with crystals. This pellicle falls 
apart in handling the tube. (The Lewis organism makes a persistent 
pellicle.) 
Fermi’s solution. —In 2 days there is a faint clouding at tempera¬ 
tures of 25 0 to 28° C. The clouding is still faint in 2 weeks. In older 
cultures an incomplete pellicle is formed. There is no green fluorescence 
with age. A culture 3 months old is Ridgway’s old gold color. (The 
Lewis organism produces green fluorescence.) 
Cohn’s solution. —There is no growth in Cohn’s solution. (The 
Lewis organism grows in Cohn’s solution without greening.) 
Uschinsky’s solution. —At temperatures 25 0 to 28° C, which are 
favorable temperatures for this organism, there is only a mere trace of 
growth in 2 days, and no heavier at 7 days. In 2 weeks clouding is better, 
* Ridgway, Robert, op. cit . 
