Isolated Brown-Pearce carcinoma cells (BPCC) were injected directly into the popliteal lymph nodes of rabbit by way of the afferent lymphatics and proliferation of the injected BPCC in the lymph nodes was studied. The chief findings are as fellows: 1. When BPCC were injected into the popliteal lymph nodes of normal rabbits which had not been sensitized with BPCC, the injected BPCC which surrived after injection into the nodes may proliferate rapidly and the nodes were replaced by proliferating BPCC nearely completely by the 14th day after injection. 2. In the lymph nodes in which an extensive proliferation of the injected BPCC had occurred, a large number of pyroninophilic blast cells appeared in the visinity of growing tumors. This is considered to be a response of lymph nodes characteristic of immune mechanisum against BPCC. 3. When BPCC were injected into the popliteal lymph nodes of the sensitized rabbits that had been inoculated with BPCC 60～70 days previously, no tumors did grow in the lymph nodes that recived an intranodal injection of BPCC.