Abstract
1. As a whole, from the results of the above-described investigations, it was possible to conclude that the coccobacillus isolated from the local lesions in the earlier stage of avian diphtheria played some important role as a causal agent of this disease.
2. The results of the treatment with the serum taken from the animals hyperimmunized against this organism proved to be uniformly favorable in the prevention of this disease. However, as far as I could judge from clinical observations regarding the therapeutic value of this serum, it seemed that the cases treated in earlier stage of the disease might be benefited, but that no marked effects followed in advanced cases.
3. The immune serum against the coccobacillus possessed powerful agglutinating and opsonic properties, but no other antibodies could be demonstrated.
