THE BACILLUS MELITENSIS 799 



Bacillus of Cattle Abortion (B. Abortus of Bang). We have 

 already mentioned, in speaking of the organism which causes abor- 

 tion in mares, that there was another bacillus described by Bang 10 

 in 1897 which was found by him to be the etio logical factor in 

 abortion of cattle, but which was distinctly different from that 

 subsequently found by Smith and others in the analogous disease 

 of horses. This organism has been observed by a great many writers 

 since Bang, and it was Smith who first pointed out its similarity 

 to the B. bronchisepticus of canine distemper and to a bacillus 

 which causes epidemic pneumonias in guinea pigs. Alice Evans 11 

 subsequently pointed out the similarity of B. Abortus and of B. 

 bronchisepticus, to the B. melitensis which causes Malta fever. 

 Evans' description of Bacterium Abortus as studied from strains 

 obtained by the Dairy Division of the Bureau of Animal Industry, 

 United States Department of Agriculture, is as follows : 



It is a short, slender pleomorphic rod with rounded ends, some- 

 times so short as to appear coccoid. Obtained from the condensa- 

 tion water of a twenty-four hour culture on agar, it is non-motile 

 and does not form spores. It is Gram-negative. 



It is difficult to grow on artificial media on first isolation, and 

 in these early cultures its growth is favored by partial anaerobiosis, 

 which Evans obtained by incubation in a closed jar in the presence 

 of cultures of B. subtilis. Glycerin or serum agar are favorable 

 media for isolation, but after prolonged cultivation it grows well 

 on ordinary media. Colonies on agar plates develop after about 

 two days in very small dewdrop form. It never heavily clouds 

 broth. Milk is rendered slightly alkaline. On potato there is a 

 slight grayish brown growth after several days, and subsequently, 

 the brownish tinge discolors the potato itself. It forms no acid 

 or gas on any of the sugars, but slightly reduces the hydrogen ion 

 concentration of broth cultures. It produces ammonia from amino 

 acids such as asparagin. It does not liquefy gelatin. 



It is easily distinguished from B. bronchisepticus by its lack of 

 motility, and less rapid and abundant growth on artificial media, as 

 well as by agglutination reactions. Evans states from her studies 

 that B. melitensis is closely related to B. abortus and can be dis- 

 tinguished from it only by means of agglutination tests. Fleischner, 



10 Bang. Zeit. f. Tier Med., 1, 1897, 241. 



11 Evans, Jour. Infec. Dis., 22, 1918, 580. 



