New YorK AGRICULTURAL EXPERIMENT STATION. Eee 
and the pellicle which would have resulted is destroyed and 
may not be reformed. } 
While this delicate pellicle may be taken as characteristic’ 
for the entire collection of cultures, six members of the B. 
221.1113022 group—B. olercaceae, CI, 0.2f, Miller Stalk 3 
No. 5, Riverhead Stalk 2 No. 1 and Miller Stalk 3 No. 1— 
‘ have from time to time shown a pellicle somewhat stronger 
than the rest, which tends to hold together when shaken. The 
reasons for this variation have not been more closely determined. 
Agar colonies. Townsend in his description of B. aroideae”® 
laid some stress on the diagnostic value of radiating surface 
colonies which appeared on lightly seeded agar plates that 
had been inoculated from fresh cultures and been held at 22° 
to 85° C. Early in the work some attention was given to this 
point, particularly at the Vermont laboratory. It was found 
that on lightly seeded plates these radiating amoeboid-shaped 
colonies were usually produced by B. aroideae, Spieckermann’s 
Bacillus and Turnip Rot D, lending color to the idea that the 
absence of gas formation was in some manner correlated with 
a tendency to the formation of these colonies. However, the 
formation of these colonies was not restricted to these organ- 
isms and on at least one occasion they were formed by 0.2 f, 
Vermont XLVIII and Turnip Rot D when they were not 
formed by B. aroideae nor Spieckermann’s Bacillus, although 
all five were tested together under parallel conditions of media, 
temperature and dilution. 
At the New York laboratory no systematic study was made 
of this point partly because the work at the Vermont labora- 
tory indicated that it had no diagnostic value and largely 
because variations in moisture and temperature effect such 
marked changes in the colony growth of practically all bac- 
teria. The occasional formation of radiating colonies was 
observed in connection with a considerable number of the 
Townsend, C.-O. A soft rot of the calla lily. U. 8S. Dept. of Agr. 
B. P. I., Bul. 60, pp. 17 and 39. 1904, 
