In a previous paper1 we called attention to the fact that the blood serums of children consuming milk from cattle infected with contagious abortion often contain antibodies against Bacillus abortus.
Contagious abortion of cattle has been known to stockmen and dairymen the world over for the past century or more. There is probably no disease or combination of diseases which distresses the dairyman more or causes greater economic loss to him than this particular infection.
Up to the year 1896 the etiology of this disease remained obscure. In that year Dr. Bang2 of Copenhagen isolated the organism which is now recognized as the specific etiologic agent in this disease. It is a short gram-negative, nonmotile bacillus which is somewhat difficult to isolate, but when once it has been grown successfully on artificial mediums its further cultivation presents few difficulties. The work of Bang shows that this bacillus is