The Effects of Spontaneous and Transplanted Rat and Mouse Tumors on the Red and White Cells in Circulating Blood and Bone Marrow*

The results of experiments reported by a number of investigators have led to the conclusion that the reactions of the host against tumor grafts are due to an immunity which develops against the transplanted tissues, and that this immunity is specific for the tumor. Thus DaFano (8) noticed in mice that after the transplantation of a piece of carcinoma of the mammary gland, lymphocytes and monocytes accumulated around the graft and became more numerous in the peripheral blood; he attributed to these cells the function of initiating an immunity against the tumor. Similarly, Murphy and Morton (22, 23) gave much attention to the behavior of the lymphocytes in the reactions against transplanted tumors. According to these investigators, an increase in the number of circulating lymphocytes is due to the development of an immunity against the tumor graft. Baeslack ( i ) held that a lack of immunity is manifested by an increase in the number of circulating polymorphonuclear leucocytes; he noticed that if a transplanted tumor grows continuously, the number of polymorphonuclear leucocytes in the circulation of the host increases. More recently, Lewis ( io) has likewise observed that as the transplanted tumor increases in size, the number of polymorphonuclear leucocytes in the peripheral circulation increases, and that the white blood cell count is highest just previous to the death of the host. However, the fact that the typical reaction occurring after homoiotransplantation of tumor is similar to that seen after homoiotransplantation of normal tissues seems to support the interpretation of Loeb (I2-2I) that the organismal differentials of normal tissues and of tumor tissues are similar or identical, and that they are responsible also in transplanted tumors, at least partly, for these changes. Furthermore, as Loeb (i22i ) has pointed out, this conclusion is also sustained by the fact that normal homoiogenously transplanted