The occurrence of abnormal cells in the peripheral blood of patients with Hodgkin's disease has been described in the literature. In the present investigation several varieties of cells were found, two of which are believed to be typical of the disease. The significance of these cells in the peripheral blood is not yet clear, but there seems to be a correlation between the presence of these characteristic cells in the blood and involvement of the spleen by the disease as determined by microscopical examination. In 11 patients both abnormalities proved to be absent; 13 out of 14 other patients showed both the abnormal cells in the blood and Hodgkin lesions in the spleen.If circulating abnormal cells are indeed an indication of the presence of Hodgkin's disease in the spleen, involvement of this organ is likely to be due to or to give rise to haematogenous dissemination. The other possibility remains that both the occurrence of abnormal cells in the peripheral blood and splenic involvement are due to a multicentric origin of the disease. It seems most unlikely that the splenic lesions are consistent with localized disease still restricted to the lymphoid system. These findings challenge the validity of the present widely used so-called Rye classification of clinical stages in Hodgkin's disease.