Apr. is, 1921 
Bacterial Spot of Tomato 
133 
abundant, spreading with an entire margin, convex, smooth, glistening, 
and translucent. At 2 days the color was marguerite yellow, and at 5 
days it was naphthalene yellow with short parallel striations of denser 
color perpendicular to the margin and a granular or netted pattern 
through the center. At 9 days the color was a straw to amber yellow, 
and the surface of the agar was covered by the profuse growth. The 
consistency was gelatinous.. The color of the agar was unchanged. 
There was no odor. 
On plain 2 per cent dextrose agar the growth was almost as vigorous 
as on potato agar and at 4 days was a marguerite yellow. 
Gelatin plates. —On gelatin plates incubated at 18 0 C., circular 
yellow colonies 3 to 5 mm. in diameter were visible in 5 days. Lique¬ 
faction was at once evident as saucer- or cup-shaped cavities under the 
colonies, and very soon the entire contents of the plates were liquefied. 
Gelatin slabs. —In stab cultures held at 18 0 C., scanty growth at the 
surface and a filiform growth along the upper half of the stab were visible 
in 3 days. In 4 days liquefaction was evident in a cup-shaped cavity 
on the surface. The subsequent liquefaction was of the stratiform type, 
progressing slowly downward until in a month the liquefied portion was 
2 to 3 cm. deep. There was a yellow precipitate at the bottom of the 
liquefied portion. No change occurred in the color of the gelatin. 
Potato cylinders. —On steamed potato cylinders growth was more 
profuse than on any other culture medium. In 2 days the growth was 
abundant, spreading, raised, smooth, glistening, and butyrous or gelati¬ 
nous in consistency, and a naphthalene yellow in color. In 5 days the 
color had deepened to a straw yellow and later became amber yellow. 
In 10 days the cylinder was completely immersed in the gelatinous bac¬ 
terial growth. The color of the potato tissue was not altered. 
On sterile uncooked potato cylinders growth appeared in 2 days and 
was abundant in 4 days but was checked by drying of the medium. A 
conspicuous channel, lined with blackened slime, marked the path of the 
needle stroke. Microscopic examination of the disintegrated tissue 
showed the cells separated to some extent by middle lamella solution 
and the cell walls brown in color. On sterile green tomato disks simi¬ 
larly inoculated a blackened channel was also formed, but the subse¬ 
quent development was much more profuse. There was no bad odor 
produced. The growth was abundant, spreading, smooth, glistening, 
and yellowish. A shallow layer of the underlying tissue was softened 
and blackened, and the tissue was darkened and water-soaked in advance 
of the rot. Microscopic examination of the affected tissue showed the 
cells separated to a limited extent as if by middle lamella solution. 
Milk. —A slow clearing without coagulation occurred in milk cultures. 
In 5 days a yellowish surface film was formed, and a slight clearing was 
visible near the surface. In 10 days the entire culture was translucent 
