These elements represent the experience and selection of the world, and especially of the Rus sian national ballet schools, where this lore has been more treasured and perfected than else where. We have made many changes in this material, to adapt it to new conditions. Let us hope that our nearly life-time's occupation with the art has enabled us to make the changes wisely, and even here and there to carry the art of Teaching Dancing to a higher point than it had there as yet reached.