SEVERAL experiments have reported transfer of behavioural modification from, one animal to another by injection of brain material 1–7, but numerous attempts to replicate the phenomenon have yielded negative results8–11. The present experiments provide a further test of the reliability of the phenomenon. The apparatus was a Grason–Stadler Model E 3125 Skinner box modified by moving the bar to the opposite side of the box and by passing a photoelectric beam across the entrance to the food magazine.