INFECTIOUS POLYARTHRITIS IN RATS

The discovery of a spontaneous infectious polyarthritis in the wild and domestic rats of Java offers investigative opportunities heretofore unavailable and has already resulted in a major contribution to experimental medical technic. Two years ago Collier and Esseveld¹ of the Eijkman Institute, Batavia, observed an adult rat (Rattus norvegicus) caught in the suburbs of Batavia which exhibited a peculiar disease characterized by considerable swelling of both hind legs, unaccompanied by signs of disease in the internal organs. The Java pathologists were able to transfer this disease to normal rats by the plantar injection of arthritic joint exudate. About two weeks after such injection the bones of the injected hind leg became remarkably enlarged, x-ray examination showing not only increases in size but distortions in outline and exostoses. Two weeks later similar arthritic changes were usually demonstrable in the opposite hind leg and somewhat later in both forelegs. An occasional