Note. 
138 
takes place at the upper portion of stab, beaded or filiform ; surface colony small, 
dirty white, no liquefaction on long standing. Gelatine plate colonies not characteristic ; 
small, round, and whitish. Growth on potato good; white, wet-shining, slimy, 
spreading over lower portion of plug. 
In +10 bouillon stringy filaments suspended in a clear medium, best seen on 
shaking, probably due to a readily fragmenting pellicle. 
Milk: coagulation delayed, separation of curd and whey by end of the first 
week, medium alkaline. 
Cohn’s solution : growth very scanty or absent. 
Uschinsky’s solution : no growth. 
Thermal death-point between 44 0 C. and 46° C. 
The result of a number of physiological tests may be summarized as follows: 
Litmus peptone with one per cent, dextrose : only very slight acidity indicated by 
the end of the third week ; no gas produced. Litmus peptone with one per cent, 
sucrose : similar results to that of dextrose. Peptone with one per cent, lactose : 
neither acid nor gas. 
No reduction of nitrates. No production of indol. Diastatic activity feeble. 
Neither acid nor gas produced in bouillon-glycerine. 
By the courtesy of Dr. Erwin F. Smith, to whom I desire to express my indebted- 
ness, cultures were obtained of Bacterium tumefaciens , the causal organism of crown 
gall in America. When inoculations were made with these cultures typical galls were 
produced, and as regards the characters enumerated above, when compared throughout 
with the organism isolated in Britain, complete agreement was found. The conclu- 
sion that the two organisms are the same was thus proved. 
During the detailed study of the two bacilli a few differences from the characters 
recorded by Dr. Erwin F. Smith and his collaborators were found. Thus the thermal 
death-point proved to lie between 44°C. and 46° C. compared with that of 5i°C. 
recorded by Dr. Smith. 1 The acidity produced in dextrose and sucrose was so slight 
that the classification of the organism as an acid producer seems hardly justifiable. 1 
No growth was observed to take place in Uschinsky’s medium, while a ‘scanty’ 
growth has been recorded. 1 
These differences apply both to the organism kindly sent by Dr. Erwin F. Smith 
and to the organism isolated in this laboratory, and in no way affect the conclusion 
just drawn that the two organisms are the same. 
Summarizing briefly the results of this investigation, it will be seen that a bacillus 
has been isolated from crown gall occurring in Britain, and the characters of this 
prove identical with those of a type culture of Bacterium tumefaciens. 
In conclusion, I wish to express my thanks to Dr. W. Robinson, who suggested 
this work, for the invaluable help and advice given during the course of this investi- 
gation. 
H. WALKDEN. 
Barker Cryptogamic Research Laboratory, 
University of Manchester. 
1 Smith, Erwin F., Brown, Nellie A., Townsend, C. O. : Crown Gall of Plants: its Cause 
and Remedy. Bull. 213, Bureau Plant Industry, U.S. Dept, of Agriculture, 1911, p. 120, 
pp. 114-16. 
