Failure to induce in rabbits effective immunity to a mixed infection of Fusobacterium necrophorum and Corynebacterium pyogenes with a combined bacterin. Onderstepoort Journal of Veterinary Research, 44 (4), 253--2;6 (1977). Rabbits were immunized with alum-precipitated, oil adjuvant and an untreated bacterin composed of F. necrophorum and C. pyogenes. Immunized rabbits were challenged intradermally with a mixture of F. necrophorum and C. pyrogenes. Immunized rabbits were challenged intradermally with a mixture of F. necorphorum and C. pyrogenes. Initially a low level of initial transient resistance could be demonstrated but a solid immunity could not be established.