Abstract
USING a modification of the “granuloma-pouch” technique—which had originally been designed for the quantitative assessment of inflammation (Selye, 1953a, 1953b)—it has been possible to expose connective tissue to 100% croton oil for periods of many months and thus to induce transplantable malignant neoplasms by treatment with this inflammatory irritant alone (Selye, 1954a). One of the cancers so induced, “croton-pouch tumor No. 2,” originated as a typical fibrosarcoma in the croton-oil treated animal, but after a few animal-passages, it developed a tendency to form cartilaginous and bony islets so that it now bears the characteristics of a fibro-chondro-osteosarcoma. It takes in 100% of the cases when transplanted as a tissue-suspension, intramuscularly or into a subcutaneous air-sac (such as is used for the production of granulomapouches), into Sprague-Dawley rats, but Wistar rats appear to be immune to it. Grown in the granuloma-pouch it produces large quantities of a viscous exudate which is extremely toxic and renders the blood incoagulable, when injected intravenously.