Biology!

A thick wall: around the cell. A moat after the wall, inside the cell. Another wall around the nucleus. A deep moat, after the wall of the nucleus! After that: this nucleolus: the heart of the cell! In a hundred years it is impossible to pass wall after wall one after another, and penetrate the heart of a cell: so true and blue. No! In a hundred years it is impossible that you came from outside each of my cells, so clearly mingled with me: against loneliness!...