Sept. 1 . 1924 
Bacterial Pustule of Soybean 
245 
were first observed (PI. 6, A) they 
were called reticulations , but this term 
does not as well describe the appear¬ 
ance in most of the later isolations as 
does “convolutions.” 
Another rather common type of 
markings is “radiating lines.” These 
^tre sometimes very distinct (Pl. 6, B). 
sometimes much less striking (Pl. 
6, G). 
A third and much rarer type for 
Bact. phaseoli sojense is that of “ con¬ 
centric striae” (Pl. 6, E). 
Very often more than one of these 
types is found on the same plate and, 
on the other hand, the author has never 
seen a plate in which there were not 
some surface colonies with no markings 
at all. The markings have never been 
-observed on very thickly sown plates. 
Thus far no explanation of the ap¬ 
pearance or nonappearance of these 
markings has been found. The fol¬ 
lowing observations have been made: 
Age and titration of the beef 
agars used.- —The variations in the 
age and reaction of the agar apparently 
have no effect on the type of colony 
produced. 
Convoluted colonies. —On agar 2 to 
16 days old at the time of inoculation 
and titrating+10 to+ 15 Fuller’s scale 
(P h 7.2 to P h 6.7 approximately). These 
figures refer to the titration immediate¬ 
ly after the final sterilization of the 
agar. +10 to +15 Fuller’s scale beef 
agar may become 2° (Fuller’s scale) 
more acid upon standing 2 weeks. 
Colonies with radiating lines. —On 
agar 2 to 16 days old at the time of 
inoculation and titrating +11 to +15 
Fuller’s scale (P H 7.1 to P H 6.7, ap¬ 
proximately) . 
Concentrically striated colonies. —On 
agar 4 to 9 days old at the time of 
inoculation, titrating +14 to +15 
Fuller’s scale (P H 6.8 to P H 6.7 ap¬ 
proximately) . 
Plates containing no colonies with 
markings of any kind. —On agar 1 day 
to 3 months old at the time of inocula¬ 
tion, titrating +14 to +15 Fuller’s 
scale (Ph6.8 to P H 6.7, approximately). 
The fact that both marked and un¬ 
marked colonies, and colonies with 
various types of markings, appeared 
on the same plates would indicate at 
the outset that in these experiments 
the variations in the agar used had 
little, if any, influence. The marked 
colonies were in all portions of the 
plates (Pl. 5, A), hence a varying 
depth of agar because the plates were 
not entirely flat on the bottom could 
not be the cause of colony variation. 
Length of time in the plant (that 
IS, TIME OF INOCULATION TO TIME OF 
isolation). —All types were found in 
both young and old infections: 
Convoluted colonies. —Plated from in¬ 
fections 15 days to 2J^ months old. 
Colonies with radiating lines. —Plated 
from infections 8 days to 3 months 
old. 
Concentrically striated colonies. —Iso¬ 
lated from infections 15 days to 2J^ 
months old. 
Plates containing no colonies with 
markings of any kind.- —Poured from 
infections 8 days to 2J^ months old. 
All types have been obtained in the 
plates poured from artificial infections 
with Bact. phaseoli sojense on both soy¬ 
bean and Phaseolus. 
Genealogy of colonies with in¬ 
ternal markings. —There is a ten¬ 
dency for the variously marked colonies 
to remain true to type after passage 
through the plant. 
Convoluted colony 8, May 26 , 1919 
(Pl. 6, C).—Out of seven platings 
from infections produced by this 
colony, six contained convoluted col¬ 
onies. The six platings were from 
four (possibly six) different plants of 
soybean, Lima and bush string bean. 
Three of these platings also contained 
concentrically striated colonies (Pl. 6, 
E), and one contained only colonies 
with no markings at all. 
Convoluted colony 1, August 6, 1917 
(like PL 6, A).—Five of eight platings 
from plants inoculated with this colony 
gave convoluted colonies. The five 
platings were from four (possibly five) 
different plants of soybean. Two 
sets of plates contained only unmarked 
colonies and one contained those with 
radiating lines (Pl. 6, B). 
Concentrically striated colony 11, 
December 5, 1919 (like Pl. 6, E).—Two 
sets of plates were poured from in¬ 
fections produced by this colony. 
In both cases striated colonies were 
present and in one set of plates con¬ 
voluted colonies also. The plates were 
poured from two different plants, soy¬ 
bean and string bean. 
Colony with radiating lines. —Colony 
1, April 26, 1919 (Pl. 6, B). From the 
single set of inoculations made with 
this colony only colonies of the same 
type and unmarked colonies have been 
isolated. 
Colony with no markings. —Colony 6, 
October 20, 1919. Colonies of all the 
types above mentioned appeared in 
two sets of plates from infections with 
this colony. In one set of plates from 
soybean, convoluted, striated, and 
unmarked colonies were present; in 
the other, from wax bean, colonies 
with radiating lines and unmarked 
ones were present. 
