Abstract
1. Sarcoma cultivated in plasma from immune animals grows quite as vigorously as in plasma from normal and tumor-bearing animals, thus affording further proof of the absence of specific cytolytic substances in the body fluids of animals immune to transplantable cancer. 2. Animals may be successfully inoculated with sarcoma cultivated in vitro, although, in the case of rat sarcoma, there is evidence of diminished virulence. 3. Subcultures of sarcoma cultivated in vitro may be made by transferring to fresh plasma the original piece of tissue, or a portion of the outgrowth. The duration of life of sarcoma cells under these conditions seems dependent only on a renewal of the medium.