1897.] 
(D) 
The Bacterial Diseases of Plants : 129 
reaction, accompanied by a smell recalling ammonia 
and amin bases. 
Checks did not develop this rot. In sterile water 
they either remained sound for weeks or else, in case 
the skins were not thoroughly sterilized, contracted a 
different kind of decay, due chiefly to Bacillus fluore- 
scens. 
Yes. In case of the tubers which were in the fluid 8 
days the softened spots contained large numbers of 
bacteria (bacilli), which, when critically examined, 
turned out to possess all the morphological and bio- 
logical characters of the bacteria obtained by pure 
cultures from the wet rotted potatoes, and from which 
the nutrient solutions had been inoculated. At the 
same time that the tubers were examined the solu- 
tions were subjected to an exact bacteriological inves- 
tigation. In two instances no other bacteria were 
found in them than the sort which had been put in 
purposely. In the third case, several other bacteria 
were present, indicating that the skin of the tuber had 
not been completely sterilized. 
In case of the tubers which remained in the fluid 
14 days, the bacteria in the softened tissue around the 
cavities were isolated and found to be identical with 
those used for inoculating the fluid. In two cases 
also, only the inoculated form was obtained in cultures 
made from the nutrient fluid surrounding these tubers, 
and consequently there could be no doubt that the 
destruction of the tissues was due to these bacteria. 
Similar cultures were made from the tubers left in 
the broth 20 days, and with the same results. When 
cultivated out, the bacteria swarming in the rotten 
tubers proved to be morphologically and biologically 
‘identical with the form originally inoculated into the 
nutrient solution in which the tuber lay, and from 
which alone the infection could result. In brief, the 
previously sound potatoes became infected and wet 
rotten as a result of the action of the bacteria intro- 
