An Unidentified Pleuropneumonialike Organism Isolated During Passages in Chick Embryos

Since a large number of developing eggs are employed in the making of vac- cines and the propagation of viruses and rickettsiae, it is of primary importance to detect any spontaneous -infection occurring in chick embryos, especially with' those agents that are ifiterable. In the course of passing a strain of the virus of