NOTES 
THE ISOLATION OF THE ORGANISM CAUSING CROWN GALL ON 
CHRYSANTHEMUM FRUTESCENS IN BRITAIN. — It is generally known that 
growths similar in character to those described in America as crown gall occur on 
plants of Paris Daisy {Chrysanthemum frutescens ) grown in this country; but up to the 
present the identity has not been proved. The Ministry of Agriculture 1 regards 
the identity of the two diseases as established by the resemblance of the general 
features ; the causal organism, however, so far as I am aware, has never been isolated 
from specimens of the diseased growths in Britain. 
The object of this note is to record the isolation of the causal organism in pure 
culture ; to describe its characters ; and to establish its identity with the organism 
isolated by Erwin F. Smith and Townsend 2 in America. 
The material necessary for the study of the galls was obtained from plants of the 
Paris Daisy grown in the nurseries near Manchester. 
Portions of the galls from this source were used for infecting healthy plants of the 
Paris Daisy, and reinfection was found to take place very readily. The principal 
difficulty encountered in the isolation of the causal organism was that, when the usual 
method of sterilizing the outside of the gall with mercuric chloride solution was - 
followed, the agar plates infected from the galls proved sterile. This sterility was 
probably brought about by the too rapid penetration of the sterilizing solution killing 
the organisms present. The organism was successfully isolated during August 1919 
in the following way. A young, unsterilized, carefully washed gall was split open by 
means of a sterile knife, and the broken surface thus exposed was touched with 
a sterilized flattened platinum wire which was then used to make a parallel stroke 
culture on a +10 bouillon-agar plate. Colonies of various organisms appeared, one 
of the most frequent showing a round, white, translucent, colonial growth. This 
organism was obtained in pure culture, and on using it to inoculate healthy plants of 
Paris Daisy galls regularly resulted. The same organism has been repeatedly re- 
isolated from the galls produced in this way. The characters of this organism, thus 
proved to be the causal organism of crown gall in the Paris Daisy in this country, have 
been carefully studied. 
The organism is a bacillus, rod-shaped with rounded ends ; measures unstained 
from young cultures on agar 1-2 to 1 *5 /x by 0-5 to o *6^; paired rods 2-8 to 3-0 fx 
by 0*5 to o*6./x ; motile by means of one, but occasionally two or three, polar flagella. 
Neither spores nor capsules observed. Stains readily with the usual stains, e.g. 
gentian violet, Loeffler’s methylene blue, carbol fuchsin, and carbol thionin. It is 
Gram-negative. Pseudozoogloea found in most liquid media. 
On +10 bouillon-agar, incubated at 18 0 C., colonies are visible after 48 hours ; 
surface colonies small, round, entire, translucent, and white ; maximum size 3 to 4 mm. 
On agar slopes growth moderate, white, filiform, smooth, raised, semi-transparent, 
becomes viscid with age, and is odourless. On + 10 bouillon-gelatine stab, growth 
1 Ministry of Agriculture Leaflet No. 245, Crown Gall ; also Report on Insect and Fungus 
Pests, 1918, pp. 18 and 21. 
2 Smith, Erwin F., and Townsend, C. O. : Science, N.S., 1907, vol. xxv, pp. 671-3. 
[Annals of Botany, Vol. XXXV. No. CXXXVII. January, 1921.] 
