Atlff. X, X 92 I A Souring of Beef Caused by Bacillus megatherium 695 
B. bronchisepticus. 
B. typhi murium. 
Actinomyces bovis. 
Moeller’s grass bacillus. 
B. lactimorbis. 
B. pullorum. 
B. mesentericus. 
B. prodigiosus. 
B. enteritidis. 
B. coli communis. 
B. coli communior. 
B. icier oides. 
Streptococcus mastitis. 
B. gallinarium. 
B. subtilis. 
The following organisms produced odors as described : 
Saccharomyces, slight sweetish odor. 
Blastomyces, distinct yeasty odor. 
Bacillus vulgatus , chestnut odor. 
Organism 1510-B again produced the typical sour-beef odor. 
The odor produced by organism 1510-B is strikingly characteristic; 
it is readily distinguishable from the yeasty or putrefactive odors, and 
it is not produced on raw beef by any of the other organisms used in 
this experiment. 
THERMAL AND OXYGEN REQUIREMENTS 
A facultative test of the beef-souring property of organism 1510-B 
with regard to temperature and oxygen tension was next applied. Meat 
pieces were inoculated with the organism and treated as follows for four 
days, with the results noted in each case: 
(1) Aerobically at room temperature. Produced perceptible sour- 
beef odor, though not so strong as when incubated. 
(2) Aerobically in refrigerator (o° to 4.5 0 C.). Produced a faint sug¬ 
gestion of sour-beef odor. 
(3) Anaerobically in incubator. Produced no odor. 
(4) Under partially reduced oxygen tension in incubator. No odor. 
It was concluded from these results that the organism 1510-B is an 
aerobic saprophyte with a wide range of vegetative temperatures but with 
an optimum of about 37 0 C. 
SEROLOGY 
It was then decided to determine if possible the existence of a specific 
or group agglutination reaction which would establish a relationship be¬ 
tween the organism isolated from sour beef and Bacillus megatherium. 
