556 PATHOGENIC AEROBIC BACILLI. 
a rather thin, circular layer forms about the point of puncture; this has the 
appearance of stearin; later it becomes grayish-white and the margins are 
marked by radiating lines. Upon the surface of nutrient agar a similar 
rowth occurs which has a pale-brown or reddish-gray color. Upon potato 
in the incubating oven an abundant development occurs, forming a dry- 
looking layer of a grayish-brown color and having irregularly notched mar- 
gins. Upon blood serum an abundant, grayish-white growth of cream-like 
consistence forms along the impfstrich; later this has a reddish gray color. 
This bacillus grows to the bottom of the line of puncture in stick cultures, 
and is no doubt a facultative anaérobic. 
Pathogenesis.—Pathogenic for white mice and for guinea-pigs. 
BACILLUS ENDOCARDITIDIS CAPSULATUS. 
Obtained by Weichselbaum (1888) from thrombi and embolic infarctions 
in the spleen and kidneys of a man who died from endocarditis with forma- 
tion of thrombi. 
Morphology.—Resembles Friedlainder’s bacillus, and is frequently sur- 
rounded by a capsule, which may be stained; also forms long, curved fila- 
ments, in the protoplasm of which vacuoles may be observed in stained pre- 
parations. 
Stains with the usual aniline colors, but not by Gram’s method; by 
staining with fuchsin and carefully decolorizing with diluted alcohol the 
presence of a capsule may be demonstrated. 
Biological Characters.— An aérobic, non-liquefying bacillus. Grows in 
the usual culture media at the room temperature. 
In gelatin stab cultures development occurs along the line of puncture, 
and on the surface asa rather thin, white, dry layer which resembles stearin. 
In agar plates the superficial colonies are thin, about two millimetres in 
diameter and gray in color; under a low power the margins are trans- 
parent and colorless, and the centre resembles the deep colonies; these are 
very small and grayish-white in color ; under a low power the surface is 
seen to be covered with tooth-like, projecting masses, the margin is dentate 
and has a pale-yellow color, while the centre is yellowish-brown. 
_ Pathogenes?s.—Rabbits are killed by the injection of a considerable quan- 
tity of a pure culture into the cavity of the abdomen or subcutaneously. 
BACILLUS ALVEI. 
Synonym.—Bacillus of foul brood (of bees). 
_ Obtained by Cheshire and Cheyne (1885) from the larvae in hives infected 
with ‘‘ foul brood.” The larve in the interior of cells in the comb die and 
become almost fluid as a result of parasitic invasion by this bacillus. 
Morphology.—Bacilli with rounded ends, from 2.5 to 5 4 in length (aver- 
age about 3.6 ~) and 0.8 u in diameter. Grow out into filaments and form 
large oval spores which have a greater diameter than the rods in which they 
are developed—1.07 u. 
es readily with the aniline colors usually employed, also by Gram’s 
method. 
_ Biological Characters.—An aérobic and facultative anaérobic, liquefy- 
ing, motile bacillus. Forms endogenous spores. Grows readily in the usual 
culture media at the room temperature. 
In gelatin plates small, round or oval colonies are formed, which later 
become pear-shaped; a branching outgrowth occurs about the margins of the 
colonies, and especially from the small end of the pear-shaped mass. In 
streak cultures upon the surface of gelatin growth occurs first along the impf- 
strich, and from this an outgrowth occurs consisting of bacilli in a single 
row or in several parallel rows, and forming irregular or circular figures, 
