Ten [female] rats were fed by the self-selection method for 1 mo. before mating, during pregnancy and lactation. Litters were normal, averaging 8.5 young; they were nursed for 25 days. Feeding cages are descr. During pregnancy the appetite for casein, olive oil, showed increase; for sucrose, a small decrease; for NaCl, Na phosphate. Ca lactate, a marked increase; for KC1, no change; for yeast, a slight increase; for wheat germ oil, cod liver oil, no change. During lactation there was a slight, consistent change in appetite. There was little difference in individual rats.