Cultivation of Rabies Virus in the Allantois of the Developing Chick Embryo

We have attempted to cultivate rabies virus in the allantois of the developing chick embryo following the technic described by Burnet. 1 We have not succeeded in obtaining serial passage beyond the third generation. However, a number of observations have been made on the survival and localization of the virus, which are of some interest, and are briefly summarized in this note.

In our attempt to grow the virus, the allantois of embryos of various ages were infected with brain virus and the eggs left in the incubator for varying lengths of time. At intervals the infected eggs were opened, the region of the allantois around the point of inoculation removed, triturated, passed to other eggs and at the same time the presence and concentration of virus determined by injecting various dilutions intracerebrally into mice.

At the beginning only the allantois was examined and tested for virus. When the egg was not contaminated with bacteria, the allantois appeared normal and the embryo was alive and of normal development. At times there were traumatic lesions on the allantois but these were not specific.

The results may best be grouped in series. In one group embryos 11 to 14 days old were infected with 0.1 cc of 1 :50 dilution of brain virus and the allantois examined 3 to 5 days later by inoculating a 1:10 suspension in saline intracerebrally into mice. Of 20 eggs in good condition thus tested 10 contained virus and 10 were negative.

In a second series the allantois were examined 2 hours to 14 days after infection and the concentration of virus determined by titration in mice. In one experiment the virus was present after 2 hours in a dilution of