In what relationship do these cells stand to man? Do they enter into his being as essential or only as incidental constituents? In other words, does man act as organ for the cells and the cells as organs for man only here in time; or, such existence being for the present postulated, is their union extended even to a future existence? This question is of extraordinary importance because it may entirely change our conception of death. With this question settled, we should be in possession of a fact from which we could draw reliable conclusions, and this fact is briefly as follows: Within each living being a continuous renovation takes place, a successive replacing of the individuals which belong to that being’s spiritual body. Human beings constitute, as already pointed out, the cells or the spiritual body, in an organism of a higher order, viz., of humanity. In this organism, an incessant renewal takes place, as we know, inasmuch as new generations continuously succeed each other. The same is the case with man’s own spiritual body. As the human generations in the social body, so the cell-generations in man’s body replace each other while the man, himself, all the time, remains the identical individual. The same holds good in regard to the cytoplasm, or the lower units that build up the cells. Everywhere we meet with the same phenomenon of renewal and everywhere with the same identity of the complex individual. This latter originates, develops, and passes away with a lifetime that bears a certain proportion to its complexity. While man counts his existence and development in years, the evolution of society is reckoned in hundreds and thousands of years. The cells in their turn have a lifetime measured in days, and the units forming the cytoplasm possess an individual existence perhaps lasting but a few minutes or seconds. The circulation in the body, therefore, is not confined to the material particles but comprises the spiritual body, the living units, as well. Now, the question is: What is the relationship between man living in time and these dying and unborn generations of cells, that form his body? Can we show that these living units, this spiritual body, is as necessary for man in a future existence as here in time? Then death must evidently be something else, something infinitely more than we have hitherto imagined or surmised. The point is to investigate what is mortal in man and what is immortal, and on this problem we will now proceed to concentrate our whole attention. CHAPTER III. Source of Spiritual Knowledge.