For however often a man may receive an obligation from you, if you refuse a request, all former favors are effaced by this one denial.

Never do a thing concerning the rectitude of which you are in doubt.

Let us strive the more earnestly therefore to lengthen out our span of life-- life that is poured out like water and falls as the leaf-- if not by action (the means to which lie in another's power), yet in any case by study and research; and since it is not granted us to live long, let us transmit to posterity some memorial that we have at least lived.

He [Pliny the Elder] used to say that 'no book [etc] was so bad but some good might be got out of it'.

That indolent but agreeable condition of doing nothing.

The erection of a monument is superfluous, our memory will endure if our lives have deserved it.

The happier time, the quicker it passes