Abstract
1. It has not been possible to increase the virulence of the submaxillary gland viruses of guinea pigs and rats, either by reducing the resistance of the animals by exposure to X-ray, or by the addition of testicular extract (Duran-Reynals factor). 2. In guinea pigs and wild rats with spontaneously infected submaxillary glands, the kidney has been found to contain the virus in the absence of demonstrable pathological changes. 3. Direct injection of these viruses into the kidney produces only mild, circumscribed lesions. 4. The viruses, following subcutaneous injection into white rats and guinea pigs, are widely distributed 2 weeks after injection. They are present in the submaxillary glands, cervical lymph nodes, kidney, and lung. They were not demonstrable at this time in the blood, liver, or spleen. 5. By the intratracheal injection of large doses of virus in guinea pigs and rats, an interstitial bronchopneumonia with thickening of the alveolar and bronchial walls and the presence of acidophilic inclusion bodies, can be produced. 6. No evidence was obtained to indicate that the multiplication of bacteria in the lung is greatly enhanced by the injection of these viruses.