423. The fact that love purified by wisdom in the intellect becomes spiritual and celestial cannot be so easily seen by their correspondence with the heart and lungs, because no one can see the quality of the blood by which the lungs are kept in the state of their respiration. The blood may be filled with pollutants and yet not be distinguishable from unpolluted blood. So likewise, the respiration of a merely natural person appears to be like the respiration of a spiritual person. Yet the two are nevertheless clearly distinguishable in heaven, for everyone has a respiration there that accords with his marriage of love and wisdom. Consequently, as angels are known by that marriage, so they are known also by their respiration. It is because of this that when anyone comes into heaven who does not possess that marriage, he suffers chest pain and struggles for breath like people in the agony of death. Therefore people in such a case also cast themselves down headlong from there, and do not rest until they are with people who possess a similar respiration, for these then possess by correspondence a like affection and consequent thought. [2] It can be seen from this that in one who is spiritual, it is his purer blood that is purified, which some people call the animal spirit,* and that it is purified to the extent that the person possesses a marriage of love and wisdom. It is this purer blood which corresponds most closely to that marriage. And because it flows into the body's blood, it follows that the latter blood, too, is purified by it. The contrary is the case in people in whom love has been defiled in the intellect. However, as we said, no one can investigate this by any empirical examination of the blood. But one can do so by an examination of the love's affections, since these correspond to the blood. * A supposed animating essence, purer than lymph, originating in the brain and pervading the fibers of the body.