590 
Journal o f Agricultural Research 
Vol. XXIX, No. 12 
Gi'ltner, Huddleson, and Tweed (10), 
writing on Bacterium abortus udder 
infection in bovines, refer fo the cul¬ 
tural requirements of the organism in 
milk, and ascribe Huddleson’s high 
degree of success in its primary culti¬ 
vation from the milk to the probability 
that a 10 per. cent C0 2 atmosphere, 
which he utilized, exists within the 
udder, since, according to their state¬ 
ment— 
freshly drawn milk from the healthy udder shows 
approximately this pressure of CO 2 . 
Meyer and Shaw (20), on the con¬ 
trary, seem of the opinion that the 
peculiar requirements of the abortion 
organism are observed only from 
uterine isolations, and refer to the 
results of McFadyean and Stockman 
(19), Holth (12), Schroeder and Cotton 
(22), .Evans (5), and Steck (2 If) to sub¬ 
stantiate their view. 
Huddleson (Ilf) has shown that 
sealed tubes slowly develop a 10 per 
cent CO 2 tension, the colonies develop¬ 
ing when this is reached. Cooledge 
(8) refers to the claims of certain inves¬ 
tigators that when tubes of agar are 
sealed and incubated there is a period 
when the proper amount of oxygen is 
present, owing to a partial absorption 
of oxygen by the agar. Some of the 
confusion regarding this feature may 
perhaps be ascribed to the fact that 
in the earlier investigations the writers 
may have considered certain details in 
the technic too inconsequential to 
mention, or that in the studies the 
investigators failed to take into con¬ 
sideration whether they were dealing 
with laboratory strains or with those 
which had never become accustomed 
to growth on artificial media. The 
writer was recently informed by Dr. 
W. E. Cotton that in the early isola¬ 
tions of the organisms from pigs in¬ 
fected with market milk, recorded by 
Schroeder and Cotton (22), sealing of 
the tubes was practiced, and that de¬ 
velopment of colonies required an 
incubation period of from a week to ten 
days. 
Original cultures of Bacterium abortus 
obtained from swine appear to show 
different atmospheric requirements. 
Differentiation of porcine strains of 
Bact. abortus from Bact. melitensis by 
their cultural or atmospheric require¬ 
ments may be difficult or even impos¬ 
sible. Good and Smith (11), in de¬ 
scribing their success in isolating Bact. 
abortus from a case of swine abortion 
by the Nowak method, mention having 
observed the development of colonies 
on the fourth day. “The first sub¬ 
cultures, ” they state, “grew readily in 
the air, whereas subcultures derived 
from the cow usually do not grow in 
the air until after being cultured for 
several generations by the Nowak 
method.” Since none of the original 
cultures were incubated in the air, 
they were unable to state whether 
growth would have taken place. 
Doyle and Spray U) find results 
seeming to indicate that the atmos¬ 
pheric requirements of the porcine 
organism may differ from those of Bact¬ 
erium abortus (bovine), since they men¬ 
tion having isolated the organism after 
three days’ incubation on serum-agar 
slants from guinea pigs inoculated with 
an emulsion of the placenta of a natu¬ 
rally infected sow. No mention is 
made of having subjected the cultures 
to other than normal atmospheric 
conditions. 
SUMMARY 
The isolation of Bacterium melitensis 
from guinea pigs infected by inocula¬ 
tions with blood from human cases of 
Malta fever, or with milk from goats 
affected with the disease, may be 
readily accomplished when serum-agar 
slants are sown with the infected tis¬ 
sues and incubated under normal at¬ 
mospheric conditions at 37° C. 
The original cultures develop with 
equal if not greater rapidity in a nor¬ 
mal atmosphere than in one partially 
displaced by C0 2 gas. This character¬ 
istic permits the differentiation of Bact¬ 
erium melitensis and Bact. abortus 
(bovine) in primary isolations. 
Since artificially cultivated strains of 
Bacterium abortus do not promptly be¬ 
come exacting in their atmospheric re¬ 
quirements when again introduced into 
animals, the biological characteristics of 
such strains may be identical with 
those of Bact. melitensis. 
The results of different investigators 
would suggest that the differentiation 
of Bacterium melitensis from porcine 
strains of Bacterium abortus may also be 
impossible by observations of their 
biological characteristics. 
LITERATURE CITED 
(1) Bang, B. 
1897. THE ETIOLOGY OF EPIZOOTIC ABORTION. 
Jour. Compar. Path, and Ther. 10: 125-149, 
illus. 
(2) Bruce, D. 
1887. NOTE ON THE DISCOVERY OF A MICROOR¬ 
GANISM in Malta fever. Practitioner 39: 
161-170. 
(3) Cooledge, L. H. 
1916. A STUDY OF THE PRESENCE OF BACTERIUM 
abortus (bang) in milk. Mich. Agr. Exp. 
Sta. Tech. Bui. 33, 37 p. 
(4) Doyle, L. P., and Spray, R. S. 
1920. INFECTIOUS ABORTION OF SWINE. Jour. 
Infect. Diseases 27:165-168. 
(5) Evans, A. C. 
1916. THE BACTERIA OF MILK FRESHLY DRAWN 
from normal udders. Jour. Infect. Diseases 
18: 437-476. 
