Leaves of Morya's Garden - Book 2 - Illumination (1925) - 2.1.8: 2.1.8. The nerve emanation is imponderable; it is odorless and invisible, because it is of the spirit. The product of the heart is blood, with all its earthly dimensions. Therefore, when it is said that one must feel with the heart, this means it should be adapted to the earthly plane.