APPLICATIONS OF VETERINARY RESEARCH. 
anerobie form, which would have grown as far as the bottom of the tube. The 
under-limit of the zone of growth lay exactly where the limit of the growth of 
an anerobic bacillus shows itself (necrosis bacillus, for example). This highly 
peculiar behaviour of the abortion bacillus towards oxygen made it at once 
apparent that he had to do with a distinct species, and therefore rendered it 
in the highest degree probable that there was a causal connexion between the 
organism and the disease.”* 
In further experiments Bang found that the abortion bacillus would grow 
in an atmosphere of almost pure oxygen, for the growth in liquid media— 
glycerine-broth-serum—was improved by bubbling through the broth oxygen 
and then sealing the flasks. These experiments, Bang says, “appeared to show 
beyond any doubt that for the abortion bacillus in its behaviour towards oxygen 
there are two optima—first, a degree of oxygen tension in the nutritive medium 
less than that of the atmospheric air; and second, the presence in the nutritive 
medium of a very high oxygen tension, which, however, lies somewhat under 
100 per cent. Between these two optima there is an intermediate zone in which’ 
the abortion bacillus grows badly or not at all.”*’ 
It was soon found that after several generations in the incubator under these 
special conditions, the bacillus could be grown as an ordinary surface xrobic 
growth on serum agar and even on ordinary agar. But for a considerable time 
Bang’s method and special medium was the best for obtaining primary cultures 
from an infected animal. 
More recently a most convenient and simple method has been adopted, 
namely, incubating together a number of tubes sown with the contagious abor- 
tion bacillus and a number of tubes sown with bacillus subtilis in a tightly 
stoppered Mason jar, such as is used for fruit preserving. Six or eight tubes 
are sown with the material suspected to contain the abortion bacillus, and an 
equal number of tubes are sown with B. subtilis. The tubes are placed in the 
Mason jar, the top screwed on, and the jar placed in the incubator, In three 
days’ time the minute dew-drop-like colonies of the abortion bacillus are seen. 
The role of the B. subtilis is to use up oxygen, of which it is very greedy, at a 
rapid rate, so as to render the atmosphere in the jar suitable for the growth of 
the abortion bacillus. 
But now to consider the proof of the réle of the bacillus discovered by Bang. 
Firstly, it may be stated that the micro-organism can be readily found in the 
great majority of cases of bovine abortions. Smears from the cotyledons of the 
foetal placenta usually show immense numbers of the bacilli. ‘The discharge 
which follows on after the act of parturition is similarly rich in the specific 
organisms. The common putrefactive organisms of the air, however, infect these 
discharges, as well as the vagina and uterus, very soon, and consequently smears 
taken more than a few hours after parturition are contaminated with a variety 
of organisms, and so the abortion bacillus may be missed. For a similar reason 
cultures made by sowing suitable media with material from the uterine dis- 
charge will be found contaminated unless taken immediately after parturition. 
Good smears and pure cultures can very often be obtained from the slimy con- 
tents of the fetal stomach (abomasum). 
In cows showing any premonitory signs of abortion the bacillus can be 
recovered in pure culture, by destroying the cow and removing the uterus 
unopened, then opening it and sowing out some of the exudate found between 
the foetal envelopes and the uterus, 
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