Percutaneous inoculation of lymph nodes

Injections into rat lymph nodes are easily performed percutaneously, without the need for a skin incision, if the nodes are enlarged in advance. The requisite enlargement of the popliteal lymph node can be obtained in 2 or 3 weeks by a single injection of tin powder or other particulate material into the foot. This method may be especially useful when multiple intranodal inoculations are contemplated.