How are we to do it? In the first place we have the actual, visible, material body--Man, so called, though, in fact, but his outer shell--to deal with. Let us bear in mind that Science teaches us that in about every seven years we change skin as effectually as any serpent; and this so gradually and imperceptibly that, had not science after years of unremitting study and observation assured us of it, no one would have had the slightest suspicion of the fact.... Hence, if a man, partially flayed alive, may sometimes survive and be covered with a new skin, so our astral, vital body .... may be made to harden its particles to the atmospheric changes. The whole secret is to succeed in evolving it out, and separating it from the visible; and while its generally invisible atoms proceed to concrete themselves into a compact mass, to gradually get rid of the old particles of our visible frame so as to make them die and disappear before the new set has had time to evolve and replace them.... We can say no more. A correct comprehension of the above scientific process will give a clue to the esoteric meaning of meditation or contemplation. Science teaches us that man changes his physical body continually, and this change is so gradual that it is almost imperceptible. Why then should the case be otherwise with the inner man? The latter too is developing and changing atoms at every moment. And the attraction of these new sets of atoms depends upon the Law of Affinity--the desires of the man drawing to his bodily tenement only such particles as are necessary to give them expression. For Science shows that thought is dynamic, and the thought-force evolved by nervous action expanding itself outwardly, must affect the molecular relations of the physical man. The inner men, however sublimated their organism may be, are still composed of actual, not hypothetical, particles, and are still subject to the law that an "action" has a tendency to repeat itself; a tendency to set up analogous action in the grosser "shell" they are in contact with, and concealed within.--"The Elixir of Life"