By the time he is four or five weeks old it is safe to play with him, a little every day, and Froebel has made his Play with the Limbs one of his first educational exercises. In this play the mother lays the baby, undressed, upon a pillow and catches the little ankles in her hands. Sometimes she prevents the baby from kicking, so that he has to struggle to get his legs free; sometimes she helps him, so that he kicks more freely and regularly; sometimes she lets him push hard against her breast. All the time