Search for the Brown-Pearce tumor XYZ factor in rabbit spleen.

SummaryThe Brown-Pearce tumor XYZ factor could not be prepared from the spleen of normal rabbits nor from the spleens of rabbits previously injected with the factor. There were two experiments comprising 52 rabbits and further controlled by prior experiments involving 110 young rabbits likewise injected intra- or subcutaneously with the Brown-Pearce tumor.