Spleen and liver size and total liver folate from mice in the preleukemic phase. Mice were fed folate-free and control diets as described in the Materials and Methods and the Fig 1 legend. From 10 to 30 mice were killed at 2, 6, 9, 12, and 52 weeks. Those killed at 52 weeks had no signs of leukemia. (A) Nucleated spleen cells. (B) Liver weights. (C) Total liver folate. The early increase in size of the livers is due to growth from weanling mice into adults. Data are ± 1 SEM. of 10 to 30 mice.