Attenuation of the living agents of cyanolophia

Abstract

Paschen¹ (1911) says that leucocytes must play an important part in the process of immunization. This remark seems partly justified in the attenuation process of cyanolophia. The living agents of cyanolophia are differently affected in tissue cultures of red bone marrow from white bone marrow.

This proves that the virus can be kept alive six days at a temperature of 38° C. in a tissue culture of red bone marrow. Chickens No. 1 and No. 3 died in 48 and 38 hours. Chicken No. 2, which had been inoculated with serum B that had been kept 6 days in the tissue culture, died twenty-four hours later than the chicken which had been inoculated with serum B that had been only three days in a tissue culture of red bone marrow. This proves a certain attenuation by the cultivation of virulent serum in red bone marrow.

The living agents, which probably cause cyanolophia, can be cultivated in red bone marrow tissue cultures even longer than six days without losing their virulence.

So we can keep virulent the living agents of cyanolophia outside of the chicken 6-8 days at 38° C., yet in the tissue culture of red bone marrow the virus dies after 12 days. This is a perfect analogue to the experiment of Marchoux,¹ who cultivated the virus of cyanolophia in a culture medium which contained red blood corpuscles. He even believed that the living agents of cyanolophia had multiplied and produced a much stronger virus than that he inoculated in his cultures. In tissue cultures of red bone marrow no multiplication of the virus was observed, but a certain attenuation, as proved by the prolongation of the incubation period.