5560. The societies of spirits to which the cartilages and bones correspond are very many; but they are such as have little spiritual life in them, just as there is little life in the bones as compared with the soft parts which they enclose-as for example in the skull and the bones of the head compared with either brain and the medulla oblongata and the sensitive substances there; and also as in the vertebrae and ribs in comparison with the heart and lungs; and so on.