36 THE BACTERIA OF THE APIARY, 



samples received from New York State and in some received from 

 Pennsylvania. 



Bacillus alvei. 



Occurrence. — This bacillus was found in all samples of European foul brood 

 examined. 



Morphology. — The bacillus is a motile, rod-shaped organism, occurring singly 

 and in pairs, and varying when taken from the surface of agar from l.'2a 

 to 3.9/x in length, and from 0.5/i. to 0.7,11 in width. Involution forms are some- 

 times present. Spores are produced and occupy an intermediate position in 

 the organism. They are oval and vary from 1.5^ to 2/a in length and from 

 0.7/a to V ill breadth ; they exhibit polar germination. Tlie few flagella are 

 arranged peritrichic. 



Oxygen requirements. — Tliis bacillus is a facultative anaerobe which grows at 

 room temperature, but better at 37° C. 



BouiUoii. — The medium becomes uniformly clouded in 24 hours ; later it 

 shows a tendency to clear by a settling of the organisms. A somewhat viscid 

 sediment is thus formed in the bottom of the tube. In older cultures a 

 slightly gray band of growth adheres to the glass at the surface of the me- 

 dium. The acidity is at first slightly increased, and a pellicle is sometimes 

 formed. 



Olucose. — The medium in both branches of the fermentation tube becomes 

 uniformly clouded. Gas is not formed. Reaction acid. 



Lactose. — The medium becomes uniformly clouded in both branches of the 

 fermentation tube, but the cloudiness is not so mai'ked as when glucose is used. 

 The acidity is slightly incx'eased, as shown by phenolphthalein. No gas is 

 formed. 



Saccharose. — The bouillon in this case also becomes clouded in both arms. 

 A heavier growth is observed than when lactose is used, but less than when 

 glucose is used. Acidity is slightly increased. Gas is not formed. 



Agar plates. — Small, grayish, circular colonies form in 24 hours. When many 

 are on the plate, they do not exceed 2 millimeters in diameter. Under low 

 L'lagnification they appear granular, with no definite margin. When fewer 

 colonies are on the plate, the granular center of the colony is surrounded by 

 numerous smaller but similar growths. The organism has a tendency to grow 

 into the medium rather than upon the surface. Sometimes, however, when 

 there are but a few colonies on the plate a thin, transparent growth spreads 

 rapidly over the surface. Later it takes on a brown tint. 



Agar slant. — A gray layer spreads over the surface in 24 hours, which later 

 takes on a slightly brown color. A strong, slightly viscid growth occurs in the 

 condensation water. 



Acid agar. — Growth talces place with the reactions varying from neutral to 

 +3.5 to phenolphthalein. 



Serum. — A slightly raised growth which is confined quite closely to the line 

 of inoculation appears on the surface of solidified serum. 



Potato. — On this medium the bacillus grows rather slowly at first, but after 

 3 or 4 days a milky growth is observed, which increases until a luxuriant growth 

 is formed, w'hich varies from a lemon-yellow to a gray color, and which later 

 becomes tinted with brown. 



Milk. — Acidity is increased after inoculation. Coagulation .usually takes 

 place after the third day. 



Litmus milk. — Much of the blue color is discharged, leaving the coagulated 

 milk of a light brown. 



