A CHANGE IN RABBIT FIBROMA VIRUS SUGGESTING MUTATION III. INTERPRETATION OF Fn~mCS

In the preceding two papers (1, 2) we have described aberrant strains of rabbit fibroma virus, a virus which normally gives rise to fibroma-like growths at the site of inoculation in cottontail or domestic rabbits (3). Those chiefly studied were derived from a growth in one cottontail rabbit (A); the strain in its original form is designated "original fibroma virus," fibromatous virus or OA strain. One of the atypical strains, first studied in England and designated as inflammatory virus or IA, produced only necrotic and inflammatory reactions on injection. The second was observed in America and called "changed virus;" the lesions produced by this in part resembled those of the original, in part those of the inflammatory strain. Similar changes were seen in the lesions produced by a virus originating from another cottontail growth (B strain), but they have not been as carefully studied.