DISEASES DUE TO BACTERIA 137 
converted into a soft, watery mass, held by the tough 
skin. These water bags may hang for a time, but soon 
burst and scatter the bacteria-infested contents over 
the leaves below. The watery mass is very attrac- 
tive to insects, which are instrumental in spreading the 
disease. 
The disease is caused by the common soft rot-pro- 
ducing organism, Bacillus carotovorus Jones. 
Investigations undertaken by the author indicated 
that the disease may be controlled most efficiently by 
limiting insect life about the plants. At one nursery 
where the disease attained epidemic proportions a deep 
ditch, filled with vegetation and eminently suitable as a 
breeding place for insects, ran alongside the houses. 
Sucking insects allied to the mosquito group abounded 
in the houses, and were observed to feed on the disrupted 
rotten tomatoes. The ditch was cleaned out and covered. 
in, and with the consequent disappearance of the insects 
soft rot of the fruits ceased to spread and finally 
disappeared also. 
(6) Brown Rot.—This disease may be identified by 
the appearance of hard, dark brown circular patches, 
smooth at first, but afterwards becoming wrinkled. 
Later the tissues become disorganized and a soft rot 
results, the fruits becoming mere water bags. This rot, 
due to an unnamed bacillus, may be distinguished from 
that caused by B. carotovorus by the brown colour which 
is assumed by the affected tissues. The methods of 
transmission and control are similar to those described 
in the disease caused by B. carotovorus. The organism 
has frequently been isolated from “‘ blossom end rot” 
lesions, which appear to be very attractive to insects, 
which cause a secondary infection by introducing the 
bacillus in question. 
Soft Rot of the Arum 
For a great many years cultivators of the arum or 
