1897.] The Bacterial Diseases of Plants: 133 
change. Unlike Hueppe’s aerobic Bacillus butyricus it caused 
in the milk no formation of ammonia, leucin, tyrosin, and a 
bitter tasting substance, when kept at 25° C.—not even after 
three weeks. : 
(6) Vegetable Juices—This germ grew best of all in cooked 
potato juice to which 1-2 per cent of dextrose was added. At 
35° C., this fluid became very cloudy in 12 hours and gas 
bubbles were given off. 
(7) Salt solutions and other Synthetic media.—In dextrose solu- 
tions with addition of tartrate of ammonia or peptone and the 
necessary mineral substances (not stated what) the organism 
developed very satisfactorily with formation of carbonic acid 
and butyric acid. In a starch paste to which tartrate of 
ammonia and the common nutrient salts were added, the 
organism grew well but there was only a slight dissolving of 
the starch and no formation of butyric acid. For behavior in 
mineral solutions containing 5 per cent peptone see Biology 
10c. 
(8) Relation to Free oxygen.— Bacillus amylobacter (Clostridium 
butyricum Prazm.), as is well known, grows only on exclusion 
of the air, and since the wet rot of the potato was generally 
attributed to this organism, Dr. Kramer first started anaerobi- 
ontic cultures. The inoculated nutrient dextrose-peptone 
gelatin was poured into plates and covered with films of mica. 
At the same time anaerobiontic cultures were started in Gruber’s 
tubes, using dextrose-peptone, nutrient gelatin. The cultures 
were kept in a brood oven at 26°C. The colonies began to 
appear in 24 hours. On the plate cultures under the mica, 
after 48 hours, tiny colonies appeared which did not increase in 
size to any noteworthy extent. Colonies on the same gelatin, 
uncovered, developed rapidly, so that on the second day this 
was entirely liquefied. The liquefied gelatin smelled like 
butyric acid, i. e., distinctly like sauer-kraut. In Gruber’s 
tubes minute, dotdike colonies also appeared, but only a few 
‘of these developed any further. The larger colonies caused a 
circular liquefaction of the gelatin, 2-4 mm. broad and increas- 
ing but slightly. These experiments indicated that the organ- 
ism is not anaerobic. A more careful examination of the 
