1896.] The Bacterial Diseases of Plants : 921 
and a longer time passed than in the other cultures before 
theirown movement appeared. Nevertheless, after some hours, 
it began, and first as a simple rotation. At the same time it 
was determined that the dried bacteria had been reduced to- 
about one-half the ordinary size. But the following day they 
had resumed the ordinary size, and then also showed the 
characteristic backward and forward movement. From this 
point on the culture presented the identical phenomena de- 
scribed above. This shows that the bacteria of the maladie du 
jaune can live for a long time in a dry state, and that on dry- 
ing they are reduced to dimensions comparable to those which 
they assume in a liquid in which the alimentary substances 
‘are becoming exhausted. I infer that this dry mucilage did 
not contain spores. 
(12) Thermal Relations: 
(a) Maximum for Growth—Not determined. 
(b) Optimum for Growth.—Not determined. The organism 
grows at living-room temperatures, and also in the thermostat 
at 35° C. 
(c) Minimum for Growth—Not determined. The natural 
progress of the disease in the hyacinth fields appears to be 
slow, and probably low temperatures may have something to do 
with this. 
(d) Death Point—Not determined. 
(13) Relation to Light—Not determined. 
(14) Vitality on Various Media.—Seems to be capable of 
living for a considerable period in various media. 
(15) Effect on Growth of Reaction of Medium (acid, neutral, 
alkaline-—No statement. 
(16) Sensitiveness to Antiseptics and Germicides.—No statement. 
(17) Other Host Plants—No mention of any. Some specula- 
tion as to origin of the disease, but no facts. 
(18) Effect upon Animals.—No statement. Probably not tried. 
(III) Economic ASPECTS: 
(1) Losses—No statement as to the extent of damage done 
by this disease. The disease is spoken of in one place as the 
chief subject of his investigations, and in another place the 
organism is called a “ dangerous parasite.” > j j 
64 
