EN
In the previous investigations, mice were fed with cellular material of cows affected with leukosis, however, the experimental animals did not show any symptoms of this disease. In comparison with control groups of animals they demonstrated only differences in blood cell counts and in appearance of lymphocytic infiltrations as well as degenerations in inner organs. The experiments did not give a clear answer to question, whether the virus can be transmitted from bovine material to mice by the oral route. The present study attempts to furnish an explanation, whether the progeny of mice used in the previous experiment will show any aberrations and whether the irradiation with X-rays will cause a higher occurrence of leukosis in it, than in a control group of animals. The current literature yields some proofs that the virus of leukosis may be transmitted to progeny in rodents which do not reveal any pathologic symptoms (2, 3). It is also known, that infection with small doses of virus may induce leukosis if animals are irradiated with X-rays, even in cases, when each of these factors in the same dose does not cause the disease separately (1).