Abstract
Herpesvirus extracted from a naturally occurring frog renal carcinoma (Lucké tumor) induced virus-free Lucké tumors in developing frogs. Herpesvirus recovered from an induced tumor after incubation at low temperature of tumor fragments cultured in vitro was oncogenic when injected into developing frog embryos. With the exception of the "pure culture" requirement, this experiment fulfills Koch-Henle postulates for the identification of the causative agent of the Lucké tumor.