Lymphoid leucemia of the mouse is readily transmitted by intravenous inoculations. The majority of the mice inoculated successfully develop leucemic, a smaller number of them, aleucemic lymphadenosis. The data presented favor the view that leucemic and aleucemic lymphadenosis are essentially the same condition.
Leucemia produced by transmission is preceded by an aleucemic stage, in which the lymph nodes and the spleen are uniformly enlarged, and the white blood count and the percentage of lymphocytes are within the normal range but immature lymphocytes are numerous in the circulating blood.
Young as well as old mice may develop leucemia if leucotic material enters their circulation.
Studies of transmissible leucemia favor the view that leucemia of mammals is a neoplastic disease. The basic problem of leucemia would seem to be determination of the factors that bring about a malignant transformation of lymphoid cells.