The "I," which for the sake of the illustration must be regarded as a separate thing (although it is really only a Centre of Consciousness in the great body of Spirit), finds itself surrounded by the triple-ocean of Mind, Energy and Matter, which ocean extends into Infinity. The body is but a physical form through which flows an unending stream of matter, for, as you know the particles and atoms of the body are constantly changing; being renewed; replaced; thrown off, and supplanted. One's body of a few years ago, or rather the particles composing that body, have passed off and now form new combinations in the world of matter. And one's body of to-day is passing away and being replaced by new particles. And one's body of next year is now occupying some other portion of space, and its particles are now parts of countless other combinations, from which space and combinations they will later come to combine and form the body of next year. There is nothing permanent about the body--even the particles of the bones are being constantly replaced by others. And so it is with the Vital Energy, Force, or Strength of the body (including that of the brain). It is constantly being used up, and expended, a fresh supply taking its place. And even the Mind of the person is changeable, and the Mind-substance or _Chitta_, is being used up and replenished, the new supply coming from the great Ocean of Mind, into which the discarded portion slips, just as is the case with the matter and energy.