Various test conditions were examined to establish the complement fixation (CF) test procedures of chicken sera for practical application. From the experiment in which fresh duck, goose, and pigeon sera were tested for their cofactor (avian C′1) activity that is essential for CF reaction of avian antibody, duck serum was proved to be most suitable as cofactor. Thus, standard CF procedure was established by employing a given amount of fresh duck serum in the reaction system, and was shown to have higher reproducibility and to be more practical than the other methods previously reported. The procedure was successfully applied for detection of antibody to Newcastle disease virus in convalescent and hyperimmune chicken sera, and antibody to Mycoplasama galisepticum in convalescent chicken sera.
Necrotic symptom occurs on broad bean by local and systemic infection caused by alfalfa mosaic virus. Some factors concerning the occurence of this necrotic symptom were observed. The results are presented in this paper. 1) Occurence of necrotic symptom of inoculated leaf is closely associated with the degree of multiplication of the virus. In an inoculated young leaf which the virus increases more rapidly than in an old lower leaf, necrotic symptom appears more sever. 2) Wherever inoculation is done on any part (leaf, leaf-petiole and stem), if the virus multiplies sufficiently there, necrosis develops always almost concurrently on systemically infected apical leaves. When lower leaves and lower part of stem were inoculated, necrosis of apical leaf is difficult to appear. 3) The virus concentration in the inoculum influences remarkably the development of necrosis on apical leaves. When dense inoculum was used, the virus multiplies much more in inoculated leaf and necrosis of apical leaf appears in higher rate. 4) Appearence of necrosis of apical leaf relates with the growth stage of upper leaves. Leaves which exhibit necrosis due to systemic infection are limited to unexpanded apical leaves smaller than about 24mm in length at the time of inoculation.