A Comparative Study of Bovine Abortion and Undulant Fever, from the Bacteriological point of View

Abstract

1. Morphologically B. abortus and B. melitensis are identical. The “coccoid” form is not a constant feature and a more satisfactory generic name would be “Brucella.”2. The organisms cannot be differentiated by cultural, bio-chemical, or staining methods, or by the agglutination reaction.3. From absorption experiments, it would appear that B. melitensis is a sub-strain of B. abortus.4. Dose for dose B. abortus is much less virulent for the guinea-pig than B. melitensis, approximately about 1: 6.5. Immunisation of monkeys (one experiment only) with killed suspensions of B. abortus protected against subsequent infection with B. melitensis.In conclusion I wish to thank Professor Ledingham for much valuable advice throughout the investigation, and Dr R. St John Brooks for supplying me with cultures from the National Collection.