In the late 1950s and early 1960s, James Gowans and colleagues in Oxford University demonstrated that lymphocytes obtained from the thoracic duct of rats and mice, labeled with 3H-thymidine and reinfused intravenously, were found in spleen and lymph nodes. Chronic drainage of thoracic duct resulted in depletion of small lymphocytes, unresponsiveness to different antigens and tolerance to skin homografts (allografts).

Gowans et al., Nature 196: 651-656, 1962; Gowans and Knight, Proc Roy Soc London B 159:257-282, 1964