Meditations by Marcus Aurelius Book 10 Page 22

both the general age and time of the world, and the whole substance of it. And how all things particular in respect of these are for their substance, as one of the least seeds that is: and for their duration, as the turning of the pestle in the mortar once about. Then to fix thy mind upon every particular object of the world, and to conceive it, (as it is indeed,) as already being in the state of dissolution, and of change; tending to some kind of either putrefaction or dispersion; or whatsoever else it is, that is the death as it were of everything in his own kind.

XX. Consider them through all actions and occupations, of their lives: as when they eat, and when they sleep: when they are in the act of necessary exoneration, and when in the act of lust.

Again, when they either are