Aug. X, X 92 I 
A Souring of Beef Caused by Bacillus megatherium 691 
Organisms 1510-A and B together produced a slight sour-beef odor. 
Organisms 1510-A and C together produced a slight musty odor. 
Organisms 1510-B and C together produced a blending of sour-beef 
and musty odors. 
All of the meat pieces which were inoculated with the fungus were cov¬ 
ered with a heavy overgrowth of this organism. 
This experiment seemed to fix the responsibility for the souring of 
this specimen of beef upon organism 1510-B independently of the other 
two organisms. Both organisms 1510-A and 1510-C will therefore be 
Fig. i. A, chains of the vegetative form of the organism; B, chains of organisms in beginning sponila- 
tion forms, containing immature spores; C, completely formed spores, in which stage the chain formation 
is invariably lost. Pen-and-ink drawing from microscope with aid of camera lucida. 
disregai ded from this point as incidental and of no significance in the 
souring of beef. 
DESCRIPTION OF CAUSATIVE ORGANISM 
Various diagnostic media were then employed to determine if possible 
the identity of organism 1510—B. It was found that the morphology and 
cultural characteristics of the organism corresponded more closely to 
those of Bacillus megatherium var. Ravenellii and B. megatherium var. de 
Bary, as described by Chester, 1 than to any other organism described. 
The organism 1510-B may be briefly described as follows: 
A round-ended, chain-forming, spore-bearing, Gram-positive, aerobic, 
slightly motile rod, from 2 to 5 microns long and 2 microns wide. During 
1 Chester, Frederick I), a manuai, of determinative bacteriology. p. 271-272, 277. New York 
Poiidon. 1909. * 
50930°—21 - 7 
