4io 
Journal of Agricultural Research 
Vol. VIII, No. ix 
decidedly yellow coloration. On gelatin the colonies are always of a 
pronounced yellow color. In the slowness with which it liquefies gelatin 
and coagulates milk and in its not reducing nitrates to nitrites, it resem¬ 
bles jP. mesentericus. It is a large granular organism with metachromatic 
granules and has large spores, thus suggesting B . vulgaius . 
Bacillus orpheus White 
Occurrence. —Encountered as an occasional secondary invader in 
larvae infected with European foulbrood. 
Agar colonies. —Surface colonies small, often barely visible. Under 
a magnification of 90 diameters the colonies show a delicate, finely 
granular structure. Surface colonies may spread to any size, and a 
spreading growth may even cover the whole agar plate. Such growth 
is usually rather delicate and of a pale bluish tinge. Deep colonies are 
denser, irregular in form. 
Morphology. —In the hanging-drop the organism has a granular 
appearance, and is more slender than B . vulgaius . It occurs singly, in 
pairs, and in long chains, the division line separating individual organ¬ 
isms being difficult to make out. The ends of individual organisms 
are rounded markedly, appearing almost bluntly pointed. The spores 
are excentrically placed, and measure from 1.1 to 2.2 ju in length and 
from 0.6 to 1.2 m in width. 
Motility. —The organism is rather actively motile. 
Gram’s stain. —The organism does not stain by Gram’s method. 
Oxygen requirements. —Aerobic and facultatively anaerobic. 
Bouillon. —Frequently no growth of importance takes place until 
after 24 hours. The medium becomes turbid; often a luxuriant, gray, 
wrinkled membrane forms, and there are usually floating flakes. The 
medium is likely to clear later, with the formation of a considerable 
amount of sediment. The above characteristics of bouillon growth apply 
also to the various carbohydrate media—namely, glucose, lactose, saccha¬ 
rose, levulose, maltose, and mannite. On titration there are no definite 
reaction changes in the carbohydrate media. 
Gas production. —No gas is produced in fermentation tubes of glu¬ 
cose bouillon or in deep tubes of glucose agar. 
Serum. —A luxuriant, raised, reticulated growth occurs. There is 
little, if any, liquefaction, and the water in the butt supports a gray 
membrane. 
Potato. —The growth on potato is slight and practically invisible. 
Agar slope.—W ithin 24 hours separate areas of a delicate growth 
occur. Later the areas become confluent, and a luxuriant, gray, raised 
glistening growth appears over the whole surface. 
Milk.—M ilk is coagulated after several days. The coagulum is then 
slowly digested. 
Azolitmin milk. —The color is soon discharged to a dull pink or brown, 
coagulation taking place later. The coagulum is slowly digested. 
