The body and mind are continually changing, and are, in fact, only names of series of changeful phenomena, like rivers whose waters are in a constant state of flux, yet presenting the appearance of unbroken streams. Every particle in this body is continually changing; no one has the same body for many minutes together, and yet we think of it as the same body.
The Complete Works of the Swami Vivekananda. Mayavati Memorial Edition (ed. 1955)