REPORT OF DEPARTMENT OF BACTERIOLOGY. 97 
INTRODUCTION. 
Almost every year the attention of plant pathologists is 
directed toward soft rots of some of the fleshy vegetables and 
in the aggregate the economic losses from this class of diseases 
are large. In a number of such diseases the casual organism 
has been isolated, studied and given a specific name. These 
rot-producing organisms are often closely related, so closely, 
in fact, that in working with a freshly isolated pathogen of 
this class one is usually in doubt as to whether the culture 
under consideration is a new species or a representative of a 
species already described. - 
The attention of one of us (H) was first directed to this 
group in 1897, in connection with ‘an experimental study of the 
black rot of cabbage, at the University of Wisconsin. The soft 
rot of cabbage was observed! in the experimental fields and 
cultures made. When it was found that the organism present 
in the rotting tissue was distinct in its chromogenesis and 
other cultural characteristics from Ps. campestris, the germ 
causing the black rot of cabbage, the study of the soft-rot germ 
ras not carried further. In 1898, while studying the distribu- 
tion of Ps. campestris in Kurope, a white liquefying organism 
was again encountered in connection with a soft rot of various 
members of the turnip family. Since 1899 study of this or- 
ganism hag been in association with Mr. F. C. Stewart, Bot- 
anist at the New York Agricultural Experiment Station. 
In 1896, Mr. Stewart made successful inoculation experti- 
ments using germs isolated from diseased cabbage on Long 
Island and reproduced the soft rot as it appeared in the cab- 
bage fields. In the following year he likewise determined 
experimentally that a destructive soft rot of Amorphophallus 
simlense could be reproduced under proper conditions by the 
inoculation of a pure culture of a species of bacterium which 
he had isolated from diseased plants of this species. No ex- 
tended study of these casual organisms was conducted at this 
time. Since 1900 a comparative study of the bacteria causing 
*Russell, H. ie and Harding, H. A. A bacterial rot of cabbage and 
allied plants. Wis. Agr. Exp. Sta. Bul, 65, p. 22. 1898. 
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