46 Table 9 Distribution of Antibody Forming Cells in Various Tissues of Bluegill Immunized with Sheep Erythrocytes White^ Cells (xlO-6) Number of PFC Fisha Tissue Per 106 Cells Total 1 Blood (2 ml) 9 4 36 Kidney 100 70 7000 Thymus 18 53 954 Spleen 9 52 468 2 Blood (2 ml) 10 1 10 Kidney 184 3 552 Thymus 30 4 120 Spleen 24 2 48 (a) Bluegill were immunized intraperitoneally with 0.1 ml of 10% SRBC and were sacrificed after two weeks. (b) Hypaque-Ficoll fractionated peripheral blood cells and unfractionated organ cell suspensions were assayed for the number of white cells and the number of plaque forming cells (PFC).